rumdl_lib/rules/

md064_no_multiple_consecutive_spaces.rs

/// Rule MD064: No multiple consecutive spaces
///
/// See [docs/md064.md](../../docs/md064.md) for full documentation, configuration, and examples.
///
/// This rule is triggered when multiple consecutive spaces are found in markdown content.
/// Multiple spaces between words serve no purpose and can indicate formatting issues.
///
/// For example:
///
/// ```markdown
/// This is   a sentence with extra spaces.
/// ```
///
/// Should be:
///
/// ```markdown
/// This is a sentence with extra spaces.
/// ```
///
/// This rule does NOT flag:
/// - Spaces inside inline code spans (`` `code   here` ``)
/// - Spaces inside fenced or indented code blocks
/// - Leading whitespace (indentation)
/// - Trailing whitespace (handled by MD009)
/// - Spaces inside HTML comments, HTML tags, or HTML blocks
/// - Table rows (alignment padding is intentional)
/// - Front matter content
use crate::filtered_lines::FilteredLinesExt;
use crate::rule::{Fix, LintError, LintResult, LintWarning, Rule, RuleCategory, Severity};
use crate::rule_config_serde::RuleConfig;
use crate::utils::blockquote::parse_blockquote_prefix;
use crate::utils::sentence_utils::is_after_sentence_ending;
use crate::utils::skip_context::is_table_line;
use serde::{Deserialize, Serialize};
use std::collections::HashSet;

/// Regex to find multiple consecutive spaces (2 or more)
use regex::Regex;
use std::sync::LazyLock;

static MULTIPLE_SPACES_REGEX: LazyLock<Regex> = LazyLock::new(|| {
    // Match 2 or more consecutive spaces
    Regex::new(r" {2,}").unwrap()
});

/// Configuration for MD064 (No multiple consecutive spaces)
#[derive(Debug, Clone, Serialize, Deserialize, PartialEq)]
#[serde(rename_all = "kebab-case")]
pub struct MD064Config {
    /// Allow exactly two spaces after sentence-ending punctuation (default: false)
    ///
    /// When enabled, allows exactly 2 spaces after sentence-ending punctuation
    /// (`.`, `!`, `?`) while still flagging multiple spaces elsewhere. This
    /// supports the traditional typewriter convention of two spaces after sentences.
    ///
    /// Sentence-ending punctuation includes:
    /// - Period: `.`
    /// - Exclamation mark: `!`
    /// - Question mark: `?`
    ///
    /// Also recognizes closing punctuation after sentence endings:
    /// - Quotes: `."`, `!"`, `?"`, `.'`, `!'`, `?'`
    /// - Parentheses: `.)`, `!)`, `?)`
    /// - Brackets: `.]`, `!]`, `?]`
    /// - Ellipsis: `...`
    ///
    /// Example with `allow-sentence-double-space = true`:
    /// ```markdown
    /// First sentence.  Second sentence.    <- OK (2 spaces after period)
    /// Multiple   spaces here.              <- Flagged (3 spaces, not after sentence)
    /// Word  word in middle.                <- Flagged (2 spaces, not after sentence)
    /// ```
    #[serde(
        default = "default_allow_sentence_double_space",
        alias = "allow_sentence_double_space"
    )]
    pub allow_sentence_double_space: bool,
}

fn default_allow_sentence_double_space() -> bool {
    false
}

impl Default for MD064Config {
    fn default() -> Self {
        Self {
            allow_sentence_double_space: default_allow_sentence_double_space(),
        }
    }
}

impl RuleConfig for MD064Config {
    const RULE_NAME: &'static str = "MD064";
}

#[derive(Debug, Clone)]
pub struct MD064NoMultipleConsecutiveSpaces {
    config: MD064Config,
}

impl Default for MD064NoMultipleConsecutiveSpaces {
    fn default() -> Self {
        Self::new()
    }
}

impl MD064NoMultipleConsecutiveSpaces {
    pub fn new() -> Self {
        Self {
            config: MD064Config::default(),
        }
    }

    pub fn from_config_struct(config: MD064Config) -> Self {
        Self { config }
    }

    /// Check if a byte position is inside an inline code span
    fn is_in_code_span(&self, code_spans: &[crate::lint_context::SourceCodeSpan], byte_pos: usize) -> bool {
        code_spans
            .iter()
            .any(|span| byte_pos >= span.byte_offset && byte_pos < span.byte_end)
    }

    /// Check if a match is trailing whitespace at the end of a line
    /// Trailing spaces are handled by MD009, so MD064 should skip them entirely
    fn is_trailing_whitespace(&self, line: &str, match_end: usize) -> bool {
        // If the match extends to the end of the line, it's trailing whitespace
        let remaining = &line[match_end..];
        remaining.is_empty() || remaining.chars().all(|c| c == '\n' || c == '\r')
    }

    /// Check if the match is part of leading indentation
    fn is_leading_indentation(&self, line: &str, match_start: usize) -> bool {
        // Check if everything before the match is whitespace
        line[..match_start].chars().all(|c| c == ' ' || c == '\t')
    }

    /// Check if the match is immediately after a list marker (handled by MD030)
    fn is_after_list_marker(&self, line: &str, match_start: usize) -> bool {
        // Strip blockquote prefix to handle lists inside blockquotes (e.g., "> 1.  item")
        let before_text = if let Some(parsed) = parse_blockquote_prefix(line) {
            let prefix_len = parsed.prefix.len();
            if match_start <= prefix_len {
                return false;
            }
            line[prefix_len..match_start].trim_start()
        } else {
            line[..match_start].trim_start()
        };

        // Unordered list markers: *, -, +
        if before_text == "*" || before_text == "-" || before_text == "+" {
            return true;
        }

        // Ordered list markers: digits followed by . or )
        // Examples: "1.", "2)", "10.", "123)"
        if before_text.len() >= 2 {
            let last_char = before_text.chars().last().unwrap();
            if last_char == '.' || last_char == ')' {
                let prefix = &before_text[..before_text.len() - 1];
                if !prefix.is_empty() && prefix.chars().all(|c| c.is_ascii_digit()) {
                    return true;
                }
            }
        }

        false
    }

    /// Check if the match is immediately after a blockquote marker (handled by MD027)
    /// Patterns: "> ", ">  ", ">>", "> > "
    fn is_after_blockquote_marker(&self, line: &str, match_start: usize) -> bool {
        let before = line[..match_start].trim_start();

        // Check if it's only blockquote markers (> characters, possibly with spaces between)
        if before.is_empty() {
            return false;
        }

        // Pattern: one or more '>' characters, optionally followed by space and more '>'
        let trimmed = before.trim_end();
        if trimmed.chars().all(|c| c == '>') {
            return true;
        }

        // Pattern: "> " at end (nested blockquote with space)
        if trimmed.ends_with('>') {
            let inner = trimmed.trim_end_matches('>').trim();
            if inner.is_empty() || inner.chars().all(|c| c == '>') {
                return true;
            }
        }

        false
    }

    /// Check if the space count looks like a tab replacement (multiple of 4)
    /// Tab replacements (4, 8, 12, etc. spaces) are intentional and should not be collapsed.
    /// This prevents MD064 from undoing MD010's tab-to-spaces conversion.
    fn is_tab_replacement_pattern(&self, space_count: usize) -> bool {
        space_count >= 4 && space_count.is_multiple_of(4)
    }

    /// Check if the match is inside or after a reference link definition
    /// Pattern: `[label]: URL` or `[label]:  URL`
    fn is_reference_link_definition(&self, line: &str, match_start: usize) -> bool {
        let trimmed = line.trim_start();
        let leading_spaces = line.len() - trimmed.len();

        // Reference link pattern: [label]: URL
        if trimmed.starts_with('[')
            && let Some(bracket_end) = trimmed.find("]:")
        {
            let colon_pos = leading_spaces + bracket_end + 2;
            // Check if the match is right after the ]: marker
            if match_start >= colon_pos - 1 && match_start <= colon_pos + 1 {
                return true;
            }
        }

        false
    }

    /// Check if the match is after a footnote marker
    /// Pattern: [^label]:  text
    fn is_after_footnote_marker(&self, line: &str, match_start: usize) -> bool {
        let trimmed = line.trim_start();

        // Footnote pattern: [^label]: text
        if trimmed.starts_with("[^")
            && let Some(bracket_end) = trimmed.find("]:")
        {
            let leading_spaces = line.len() - trimmed.len();
            let colon_pos = leading_spaces + bracket_end + 2;
            // Check if the match is right after the ]: marker
            if match_start >= colon_pos.saturating_sub(1) && match_start <= colon_pos + 1 {
                return true;
            }
        }

        false
    }

    /// Check if the match is after a definition list marker
    /// Pattern: :   Definition text
    fn is_after_definition_marker(&self, line: &str, match_start: usize) -> bool {
        let before = line[..match_start].trim_start();

        // Definition list marker is just ":"
        before == ":"
    }

    /// Check if the match is immediately after a task list checkbox.
    /// Standard GFM: only `[ ]`, `[x]`, `[X]` are valid checkboxes.
    /// Obsidian flavor: any single character inside brackets is a valid checkbox
    /// (e.g., `[/]`, `[-]`, `[>]`, `[✓]`).
    fn is_after_task_checkbox(&self, line: &str, match_start: usize, flavor: crate::config::MarkdownFlavor) -> bool {
        let before = line[..match_start].trim_start();

        // Zero-allocation iterator-based check for: marker + space + '[' + char + ']'
        let mut chars = before.chars();
        let pattern = (
            chars.next(),
            chars.next(),
            chars.next(),
            chars.next(),
            chars.next(),
            chars.next(),
        );

        match pattern {
            (Some('*' | '-' | '+'), Some(' '), Some('['), Some(c), Some(']'), None) => {
                if flavor == crate::config::MarkdownFlavor::Obsidian {
                    // Obsidian: any single character is a valid checkbox state
                    true
                } else {
                    // Standard GFM: only space, 'x', or 'X' are valid
                    matches!(c, ' ' | 'x' | 'X')
                }
            }
            _ => false,
        }
    }

    /// Collect line numbers that belong to a "column-aligned" list.
    ///
    /// A list is column-aligned when it has at least two items and every
    /// item's first line contains a run of two or more consecutive spaces
    /// somewhere in its post-marker content (excluding trailing whitespace).
    /// In that case the spacing is intentional column alignment — common in
    /// `cdk init`-style "Useful commands" sections — and per-line MD064 fixes
    /// would corrupt the layout while leaving lint green. Skipping the rule
    /// for those item lines keeps detection list-consistent and the fix safe.
    ///
    /// Each list is judged on its own items: a nested list is a different list
    /// from its parent, so an unaligned child does not disqualify the aligned
    /// parent items around it, and vice versa.
    fn aligned_list_item_lines(&self, ctx: &crate::lint_context::LintContext) -> HashSet<usize> {
        let mut aligned = HashSet::new();
        for block in &ctx.list_blocks {
            for items in ctx.list_block_item_groups(block) {
                if items.len() < 2 {
                    continue;
                }
                let all_aligned = items
                    .iter()
                    .all(|&line_num| self.item_line_has_internal_alignment(ctx, line_num));
                if all_aligned {
                    aligned.extend(items);
                }
            }
        }
        aligned
    }

    /// True when the given list-item line has a run of 2+ consecutive spaces
    /// in its post-marker, non-trailing content.
    fn item_line_has_internal_alignment(&self, ctx: &crate::lint_context::LintContext, line_num: usize) -> bool {
        let Some(line_info) = ctx.line_info(line_num) else {
            return false;
        };
        let Some(item) = &line_info.list_item else {
            return false;
        };
        let content = line_info.content(ctx.content);
        if item.content_column >= content.len() {
            return false;
        }
        content[item.content_column..].trim_end().contains("  ")
    }

    /// Check if this is a table row without outer pipes (GFM extension)
    /// Pattern: text | text | text (no leading/trailing pipe)
    fn is_table_without_outer_pipes(&self, line: &str) -> bool {
        let trimmed = line.trim();

        // Must contain at least one pipe but not start or end with pipe
        if !trimmed.contains('|') {
            return false;
        }

        // If it starts or ends with |, it's a normal table (handled by is_table_line)
        if trimmed.starts_with('|') || trimmed.ends_with('|') {
            return false;
        }

        // Check if it looks like a table row: has multiple pipe-separated cells
        // Could be data row (word | word) or separator row (--- | ---)
        // Table cells can be empty, so we just check for at least 2 parts
        let parts: Vec<&str> = trimmed.split('|').collect();
        if parts.len() >= 2 {
            // At least first or last cell should have content (not just whitespace)
            // to distinguish from accidental pipes in text
            let first_has_content = !parts.first().unwrap_or(&"").trim().is_empty();
            let last_has_content = !parts.last().unwrap_or(&"").trim().is_empty();
            if first_has_content || last_has_content {
                return true;
            }
        }

        false
    }

    // Preserve the native descending replacement order, including its bounds
    // checks. This is deliberately separate from generic diagnostic edits,
    // whose overlap and line-ending behavior can differ.
    fn apply_native_fixes(content: &str, mut fixes: Vec<(std::ops::Range<usize>, String)>) -> String {
        fixes.sort_by_key(|(range, _)| std::cmp::Reverse(range.start));
        let mut result = content.to_string();
        for (range, replacement) in fixes {
            if range.start < result.len() && range.end <= result.len() {
                result.replace_range(range, &replacement);
            }
        }
        result
    }
}

impl Rule for MD064NoMultipleConsecutiveSpaces {
    fn native_format_policy(&self) -> Option<crate::format_proof::NativeFormatPolicy> {
        (self.config == Default::default()).then_some(crate::format_proof::NativeFormatPolicy::for_rule::<Self>(64))
    }

    fn name(&self) -> &'static str {
        "MD064"
    }

    fn description(&self) -> &'static str {
        "Multiple consecutive spaces"
    }

    fn check(&self, ctx: &crate::lint_context::LintContext) -> LintResult {
        let content = ctx.content;

        // Early return: if no double spaces at all, skip
        if !content.contains("  ") {
            return Ok(vec![]);
        }

        // Config is already correct - engine applies inline overrides before calling check()
        let mut warnings = Vec::new();
        let code_spans = ctx.source_code_spans();

        // Pre-compute lines belonging to column-aligned list blocks. The
        // alignment whitespace there is intentional, and per-line fixes would
        // corrupt the surrounding layout — see `aligned_list_item_lines`.
        let aligned_lines = self.aligned_list_item_lines(ctx);

        // Process content lines, automatically skipping front matter, code blocks, HTML, PyMdown blocks, and Obsidian comments
        for line in ctx
            .filtered_lines()
            .skip_front_matter()
            .skip_code_blocks()
            .skip_html_blocks()
            .skip_html_comments()
            .skip_mkdocstrings()
            .skip_esm_blocks()
            .skip_jsx_expressions()
            .skip_mdx_comments()
            .skip_pymdown_blocks()
            .skip_obsidian_comments()
        {
            // Quick check: skip if line doesn't contain double spaces
            if !line.content.contains("  ") {
                continue;
            }

            // Skip lines that belong to a column-aligned list block. The
            // surrounding items use the same intentional alignment, so flagging
            // outliers here would produce a destructive partial fix.
            if aligned_lines.contains(&line.line_num) {
                continue;
            }

            // Skip table rows (alignment padding is intentional)
            if is_table_line(line.content) {
                continue;
            }

            // Skip tables without outer pipes (GFM extension)
            if self.is_table_without_outer_pipes(line.content) {
                continue;
            }

            let line_start_byte = ctx.line_start_byte(line.line_num).unwrap_or(0);

            // Find all occurrences of multiple consecutive spaces
            for mat in MULTIPLE_SPACES_REGEX.find_iter(line.content) {
                let match_start = mat.start();
                let match_end = mat.end();
                let space_count = match_end - match_start;

                // Skip if this is leading indentation
                if self.is_leading_indentation(line.content, match_start) {
                    continue;
                }

                // Skip trailing whitespace (handled by MD009)
                if self.is_trailing_whitespace(line.content, match_end) {
                    continue;
                }

                // Skip tab replacement patterns (4, 8, 12, etc. spaces)
                // This prevents MD064 from undoing MD010's tab-to-spaces conversion
                if self.is_tab_replacement_pattern(space_count) {
                    continue;
                }

                // Skip spaces after list markers (handled by MD030)
                if self.is_after_list_marker(line.content, match_start) {
                    continue;
                }

                // Skip spaces after blockquote markers (handled by MD027)
                if self.is_after_blockquote_marker(line.content, match_start) {
                    continue;
                }

                // Skip spaces after footnote markers
                if self.is_after_footnote_marker(line.content, match_start) {
                    continue;
                }

                // Skip spaces after reference link definition markers
                if self.is_reference_link_definition(line.content, match_start) {
                    continue;
                }

                // Skip spaces after definition list markers
                if self.is_after_definition_marker(line.content, match_start) {
                    continue;
                }

                // Skip spaces after task list checkboxes
                if self.is_after_task_checkbox(line.content, match_start, ctx.flavor) {
                    continue;
                }

                // Allow exactly 2 spaces after sentence-ending punctuation if configured
                // This supports the traditional typewriter convention of two spaces after sentences
                if self.config.allow_sentence_double_space
                    && space_count == 2
                    && is_after_sentence_ending(line.content, match_start)
                {
                    continue;
                }

                // Calculate absolute byte position
                let abs_byte_start = line_start_byte + match_start;

                // Skip if inside an inline code span
                if self.is_in_code_span(code_spans, abs_byte_start) {
                    continue;
                }

                // Inline HTML is raw: spaces in a comment or inside a tag (an
                // attribute value like `title="a  b"`) are not prose to collapse.
                if ctx.is_in_html_comment(abs_byte_start) || ctx.is_in_html_tag(abs_byte_start) {
                    continue;
                }

                // Calculate byte range for the fix
                let abs_byte_end = line_start_byte + match_end;

                // Determine the replacement: if allow_sentence_double_space is enabled
                // and this is after a sentence ending, collapse to 2 spaces, otherwise to 1
                let replacement =
                    if self.config.allow_sentence_double_space && is_after_sentence_ending(line.content, match_start) {
                        "  ".to_string() // Collapse to two spaces after sentence
                    } else {
                        " ".to_string() // Collapse to single space
                    };

                warnings.push(LintWarning {
                    rule_name: Some(self.name().to_string()),
                    message: format!("Multiple consecutive spaces ({space_count}) found"),
                    line: line.line_num,
                    column: match_start + 1, // 1-indexed
                    end_line: line.line_num,
                    end_column: match_end + 1, // 1-indexed
                    severity: Severity::Warning,
                    fix: Some(Fix::new(abs_byte_start..abs_byte_end, replacement)),
                });
            }
        }

        Ok(warnings)
    }

    fn fix(&self, ctx: &crate::lint_context::LintContext) -> Result<String, LintError> {
        let content = ctx.content;

        // Early return if no double spaces
        if !content.contains("  ") {
            return Ok(content.to_string());
        }

        // Get warnings to identify what needs to be fixed
        let warnings = self.check(ctx)?;
        let warnings =
            crate::utils::fix_utils::filter_warnings_by_inline_config(warnings, ctx.inline_config(), self.name());
        if warnings.is_empty() {
            return Ok(content.to_string());
        }

        // Collect all fixes and sort by position (reverse order to avoid position shifts)
        let fixes: Vec<(std::ops::Range<usize>, String)> = warnings
            .into_iter()
            .filter_map(|w| w.fix.map(|f| (f.range, f.replacement)))
            .collect();

        Ok(Self::apply_native_fixes(content, fixes))
    }

    fn fix_with_diagnostics(
        &self,
        ctx: &crate::lint_context::LintContext,
        warnings: &[LintWarning],
    ) -> Result<String, LintError> {
        if !ctx.content.contains("  ") {
            return Ok(ctx.content.to_owned());
        }
        let fixes = warnings
            .iter()
            .filter(|warning| crate::utils::fix_utils::warning_is_enabled(warning, ctx.inline_config(), self.name()))
            .filter_map(|warning| warning.fix.as_ref())
            .map(|fix| (fix.range.clone(), fix.replacement.clone()))
            .collect();
        Ok(Self::apply_native_fixes(ctx.content, fixes))
    }

    /// Get the category of this rule for selective processing
    fn category(&self) -> RuleCategory {
        RuleCategory::Whitespace
    }

    /// Check if this rule should be skipped
    fn should_skip(&self, ctx: &crate::lint_context::LintContext) -> bool {
        ctx.content.is_empty() || !ctx.content.contains("  ")
    }

    fn as_any(&self) -> &dyn std::any::Any {
        self
    }

    crate::impl_rule_config_methods!(MD064Config);
}

#[cfg(test)]
mod tests {
    use super::*;
    use crate::lint_context::LintContext;

    #[test]
    fn test_basic_multiple_spaces() {
        let rule = MD064NoMultipleConsecutiveSpaces::new();

        // Should flag multiple spaces
        let content = "This is   a sentence with extra spaces.";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        let result = rule.check(&ctx).unwrap();
        assert_eq!(result.len(), 1);
        assert_eq!(result[0].line, 1);
        assert_eq!(result[0].column, 8); // Position of first extra space
    }

    #[test]
    fn test_no_issues_single_spaces() {
        let rule = MD064NoMultipleConsecutiveSpaces::new();

        // Should not flag single spaces
        let content = "This is a normal sentence with single spaces.";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        let result = rule.check(&ctx).unwrap();
        assert!(result.is_empty());
    }

    #[test]
    fn test_skip_inline_code() {
        let rule = MD064NoMultipleConsecutiveSpaces::new();

        // Should not flag spaces inside inline code
        let content = "Use `code   with   spaces` for formatting.";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        let result = rule.check(&ctx).unwrap();
        assert!(result.is_empty());
    }

    #[test]
    fn test_skip_code_blocks() {
        let rule = MD064NoMultipleConsecutiveSpaces::new();

        // Should not flag spaces inside code blocks
        let content = "# Heading\n\n```\ncode   with   spaces\n```\n\nNormal text.";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        let result = rule.check(&ctx).unwrap();
        assert!(result.is_empty());
    }

    #[test]
    fn test_skip_leading_indentation() {
        let rule = MD064NoMultipleConsecutiveSpaces::new();

        // Should not flag leading indentation
        let content = "    This is indented text.";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        let result = rule.check(&ctx).unwrap();
        assert!(result.is_empty());
    }

    #[test]
    fn test_skip_trailing_spaces() {
        let rule = MD064NoMultipleConsecutiveSpaces::new();

        // Should not flag trailing spaces (handled by MD009)
        let content = "Line with trailing spaces   \nNext line.";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        let result = rule.check(&ctx).unwrap();
        assert!(result.is_empty());
    }

    #[test]
    fn test_skip_all_trailing_spaces() {
        let rule = MD064NoMultipleConsecutiveSpaces::new();

        // Should not flag any trailing spaces regardless of count
        let content = "Two spaces  \nThree spaces   \nFour spaces    \n";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        let result = rule.check(&ctx).unwrap();
        assert!(result.is_empty());
    }

    #[test]
    fn test_skip_front_matter() {
        let rule = MD064NoMultipleConsecutiveSpaces::new();

        // Should not flag spaces in front matter
        let content = "---\ntitle:   Test   Title\n---\n\nContent here.";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        let result = rule.check(&ctx).unwrap();
        assert!(result.is_empty());
    }

    #[test]
    fn test_skip_html_comments() {
        let rule = MD064NoMultipleConsecutiveSpaces::new();

        // Should not flag spaces in HTML comments
        let content = "<!-- comment   with   spaces -->\n\nContent here.";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        let result = rule.check(&ctx).unwrap();
        assert!(result.is_empty());
    }

    #[test]
    fn test_skip_inline_html_comments_and_tags() {
        let rule = MD064NoMultipleConsecutiveSpaces::new();
        let content = "Text <!-- a  b --> and <span title=\"c  d\">e</span> end.\n";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        assert!(rule.check(&ctx).unwrap().is_empty());
        assert_eq!(rule.fix(&ctx).unwrap(), content);

        // Prose around inline HTML is still checked.
        let content = "Text  <!-- a -->  <b>x</b>  end.\n";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        let columns: Vec<usize> = rule.check(&ctx).unwrap().iter().map(|w| w.column).collect();
        assert_eq!(columns, vec![5, 17, 27]);
    }

    #[test]
    fn test_multiple_issues_one_line() {
        let rule = MD064NoMultipleConsecutiveSpaces::new();

        // Should flag multiple occurrences on one line
        let content = "This   has   multiple   issues.";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        let result = rule.check(&ctx).unwrap();
        assert_eq!(result.len(), 3, "Should flag all 3 occurrences");
    }

    #[test]
    fn test_fix_collapses_spaces() {
        let rule = MD064NoMultipleConsecutiveSpaces::new();

        let content = "This is   a sentence   with extra   spaces.";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        let fixed = rule.fix(&ctx).unwrap();
        assert_eq!(fixed, "This is a sentence with extra spaces.");
    }

    #[test]
    fn test_fix_preserves_inline_code() {
        let rule = MD064NoMultipleConsecutiveSpaces::new();

        let content = "Text   here `code   inside` and   more.";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        let fixed = rule.fix(&ctx).unwrap();
        assert_eq!(fixed, "Text here `code   inside` and more.");
    }

    #[test]
    fn test_fix_preserves_trailing_spaces() {
        let rule = MD064NoMultipleConsecutiveSpaces::new();

        // Trailing spaces should be preserved (handled by MD009)
        let content = "Line with   extra and trailing   \nNext line.";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        let fixed = rule.fix(&ctx).unwrap();
        // Only the internal "   " gets fixed to " ", trailing spaces are preserved
        assert_eq!(fixed, "Line with extra and trailing   \nNext line.");
    }

    #[test]
    fn test_list_items_with_extra_spaces() {
        let rule = MD064NoMultipleConsecutiveSpaces::new();

        // Multi-space within list-item content must be flagged when the
        // surrounding block isn't column-aligned. The third item has no
        // internal multi-space, so the "every item is aligned" heuristic
        // doesn't apply and items 1 and 2 are reported normally.
        let content = "- Item   one\n- Item   two\n- Item three\n";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        let result = rule.check(&ctx).unwrap();
        assert_eq!(result.len(), 2, "Should flag spaces in list items");
    }

    #[test]
    fn test_blockquote_with_extra_spaces_in_content() {
        let rule = MD064NoMultipleConsecutiveSpaces::new();

        // Extra spaces in blockquote CONTENT should be flagged
        let content = "> Quote   with extra   spaces\n";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        let result = rule.check(&ctx).unwrap();
        assert_eq!(result.len(), 2, "Should flag spaces in blockquote content");
    }

    #[test]
    fn test_skip_blockquote_marker_spaces() {
        let rule = MD064NoMultipleConsecutiveSpaces::new();

        // Extra spaces after blockquote marker are handled by MD027
        let content = ">  Text with extra space after marker\n";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        let result = rule.check(&ctx).unwrap();
        assert!(result.is_empty());

        // Three spaces after marker
        let content = ">   Text with three spaces after marker\n";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        let result = rule.check(&ctx).unwrap();
        assert!(result.is_empty());

        // Nested blockquotes
        let content = ">>  Nested blockquote\n";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        let result = rule.check(&ctx).unwrap();
        assert!(result.is_empty());
    }

    #[test]
    fn test_mixed_content() {
        let rule = MD064NoMultipleConsecutiveSpaces::new();

        let content = r#"# Heading

This   has extra spaces.

```
code   here  is  fine
```

- List   item

> Quote   text

Normal paragraph.
"#;
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        let result = rule.check(&ctx).unwrap();
        // Should flag: "This   has" (1), "List   item" (1), "Quote   text" (1)
        assert_eq!(result.len(), 3, "Should flag only content outside code blocks");
    }

    #[test]
    fn test_multibyte_utf8() {
        let rule = MD064NoMultipleConsecutiveSpaces::new();

        // Test with multi-byte UTF-8 characters
        let content = "日本語   テスト   文字列";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        let result = rule.check(&ctx);
        assert!(result.is_ok(), "Should handle multi-byte UTF-8 characters");

        let warnings = result.unwrap();
        assert_eq!(warnings.len(), 2, "Should find 2 occurrences of multiple spaces");
    }

    #[test]
    fn test_table_rows_skipped() {
        let rule = MD064NoMultipleConsecutiveSpaces::new();

        // Table rows with alignment padding should be skipped
        let content = "| Header 1 | Header 2 |\n|----------|----------|\n| Cell 1   | Cell 2   |";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        let result = rule.check(&ctx).unwrap();
        // Table rows should be skipped (alignment padding is intentional)
        assert!(result.is_empty());
    }

    #[test]
    fn test_link_text_with_extra_spaces() {
        let rule = MD064NoMultipleConsecutiveSpaces::new();

        // Link text with extra spaces (should be flagged)
        let content = "[Link   text](https://example.com)";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        let result = rule.check(&ctx).unwrap();
        assert_eq!(result.len(), 1, "Should flag extra spaces in link text");
    }

    #[test]
    fn test_image_alt_with_extra_spaces() {
        let rule = MD064NoMultipleConsecutiveSpaces::new();

        // Image alt text with extra spaces (should be flagged)
        let content = "![Alt   text](image.png)";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        let result = rule.check(&ctx).unwrap();
        assert_eq!(result.len(), 1, "Should flag extra spaces in image alt text");
    }

    #[test]
    fn test_skip_list_marker_spaces() {
        let rule = MD064NoMultipleConsecutiveSpaces::new();

        // Spaces after list markers are handled by MD030, not MD064
        let content = "*   Item with extra spaces after marker\n-   Another item\n+   Third item\n";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        let result = rule.check(&ctx).unwrap();
        assert!(result.is_empty());

        // Ordered list markers
        let content = "1.  Item one\n2.  Item two\n10. Item ten\n";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        let result = rule.check(&ctx).unwrap();
        assert!(result.is_empty());

        // Indented list items should also be skipped
        let content = "  *   Indented item\n    1.  Nested numbered item\n";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        let result = rule.check(&ctx).unwrap();
        assert!(result.is_empty());
    }

    #[test]
    fn test_skip_blockquoted_list_marker_spaces() {
        let rule = MD064NoMultipleConsecutiveSpaces::new();

        // Blockquoted ordered list with 2-space markers (MD030 ol-single=2)
        let content = "# Title\n\n> 1.  Hello.\n>     This is a list item.\n> 2.  This is another list item\n";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        let result = rule.check(&ctx).unwrap();
        assert!(
            result.is_empty(),
            "Should not flag spaces after list markers in blockquotes"
        );

        // Blockquoted unordered list
        let content = "> *   Item one\n> -   Item two\n> +   Item three\n";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        let result = rule.check(&ctx).unwrap();
        assert!(
            result.is_empty(),
            "Should not flag spaces after unordered list markers in blockquotes"
        );

        // Nested blockquoted list
        let content = "> > 1.  Nested blockquote list item\n";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        let result = rule.check(&ctx).unwrap();
        assert!(
            result.is_empty(),
            "Should not flag spaces after list markers in nested blockquotes"
        );

        // Parenthesis-style ordered markers in blockquote
        let content = "> 1)  First item\n> 2)  Second item\n";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        let result = rule.check(&ctx).unwrap();
        assert!(
            result.is_empty(),
            "Should not flag spaces after parenthesis-style ordered markers in blockquotes"
        );

        // Extra whitespace between blockquote marker and list marker
        let content = ">  1.  Item with extra space after >\n";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        let result = rule.check(&ctx).unwrap();
        // The spaces after "1." should not be flagged (list marker context)
        // The spaces after ">" are handled by is_after_blockquote_marker
        assert!(
            result.is_empty(),
            "Should not flag list marker spaces even with extra space after blockquote marker"
        );

        // Multiple spaces in blockquoted list *content* should still be flagged
        let content = "> 1.  Item with   extra spaces in content\n";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        let result = rule.check(&ctx).unwrap();
        assert_eq!(
            result.len(),
            1,
            "Should still flag extra spaces in blockquoted list content"
        );
    }

    #[test]
    fn test_flag_spaces_in_list_content() {
        let rule = MD064NoMultipleConsecutiveSpaces::new();

        // Multiple spaces WITHIN list content should still be flagged
        let content = "* Item with   extra spaces in content\n";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        let result = rule.check(&ctx).unwrap();
        assert_eq!(result.len(), 1, "Should flag extra spaces in list content");
    }

    #[test]
    fn test_skip_reference_link_definition_spaces() {
        let rule = MD064NoMultipleConsecutiveSpaces::new();

        // Reference link definitions may have multiple spaces after the colon
        let content = "[ref]:  https://example.com\n";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        let result = rule.check(&ctx).unwrap();
        assert!(result.is_empty());

        // Multiple spaces
        let content = "[reference-link]:   https://example.com \"Title\"\n";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        let result = rule.check(&ctx).unwrap();
        assert!(result.is_empty());
    }

    #[test]
    fn test_skip_footnote_marker_spaces() {
        let rule = MD064NoMultipleConsecutiveSpaces::new();

        // Footnote definitions may have multiple spaces after the colon
        let content = "[^1]:  Footnote with extra space\n";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        let result = rule.check(&ctx).unwrap();
        assert!(result.is_empty());

        // Footnote with longer label
        let content = "[^footnote-label]:   This is the footnote text.\n";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        let result = rule.check(&ctx).unwrap();
        assert!(result.is_empty());
    }

    #[test]
    fn test_skip_definition_list_marker_spaces() {
        let rule = MD064NoMultipleConsecutiveSpaces::new();

        // Definition list markers (PHP Markdown Extra / Pandoc)
        let content = "Term\n:   Definition with extra spaces\n";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        let result = rule.check(&ctx).unwrap();
        assert!(result.is_empty());

        // Multiple definitions
        let content = ":    Another definition\n";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        let result = rule.check(&ctx).unwrap();
        assert!(result.is_empty());
    }

    #[test]
    fn test_skip_task_list_checkbox_spaces() {
        let rule = MD064NoMultipleConsecutiveSpaces::new();

        // Task list items may have extra spaces after checkbox
        let content = "- [ ]  Task with extra space\n";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        let result = rule.check(&ctx).unwrap();
        assert!(result.is_empty());

        // Checked task
        let content = "- [x]  Completed task\n";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        let result = rule.check(&ctx).unwrap();
        assert!(result.is_empty());

        // With asterisk marker
        let content = "* [ ]  Task with asterisk marker\n";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        let result = rule.check(&ctx).unwrap();
        assert!(result.is_empty());
    }

    #[test]
    fn test_skip_extended_task_checkbox_spaces_obsidian() {
        // Extended checkboxes are only recognized in Obsidian flavor
        let rule = MD064NoMultipleConsecutiveSpaces::new();

        // Extended Obsidian checkboxes: [/] in progress
        let content = "- [/]  In progress task\n";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Obsidian, None);
        let result = rule.check(&ctx).unwrap();
        assert!(result.is_empty(), "Should skip [/] checkbox in Obsidian");

        // Extended Obsidian checkboxes: [-] cancelled
        let content = "- [-]  Cancelled task\n";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Obsidian, None);
        let result = rule.check(&ctx).unwrap();
        assert!(result.is_empty(), "Should skip [-] checkbox in Obsidian");

        // Extended Obsidian checkboxes: [>] deferred
        let content = "- [>]  Deferred task\n";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Obsidian, None);
        let result = rule.check(&ctx).unwrap();
        assert!(result.is_empty(), "Should skip [>] checkbox in Obsidian");

        // Extended Obsidian checkboxes: [<] scheduled
        let content = "- [<]  Scheduled task\n";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Obsidian, None);
        let result = rule.check(&ctx).unwrap();
        assert!(result.is_empty(), "Should skip [<] checkbox in Obsidian");

        // Extended Obsidian checkboxes: [?] question
        let content = "- [?]  Question task\n";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Obsidian, None);
        let result = rule.check(&ctx).unwrap();
        assert!(result.is_empty(), "Should skip [?] checkbox in Obsidian");

        // Extended Obsidian checkboxes: [!] important
        let content = "- [!]  Important task\n";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Obsidian, None);
        let result = rule.check(&ctx).unwrap();
        assert!(result.is_empty(), "Should skip [!] checkbox in Obsidian");

        // Extended Obsidian checkboxes: [*] star/highlight
        let content = "- [*]  Starred task\n";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Obsidian, None);
        let result = rule.check(&ctx).unwrap();
        assert!(result.is_empty(), "Should skip [*] checkbox in Obsidian");

        // With asterisk list marker and extended checkbox
        let content = "* [/]  In progress with asterisk\n";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Obsidian, None);
        let result = rule.check(&ctx).unwrap();
        assert!(result.is_empty(), "Should skip extended checkbox with * marker");

        // With plus list marker and extended checkbox
        let content = "+ [-]  Cancelled with plus\n";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Obsidian, None);
        let result = rule.check(&ctx).unwrap();
        assert!(result.is_empty(), "Should skip extended checkbox with + marker");

        // Multi-byte UTF-8 checkboxes (Unicode checkmarks)
        let content = "- [✓]  Completed with checkmark\n";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Obsidian, None);
        let result = rule.check(&ctx).unwrap();
        assert!(result.is_empty(), "Should skip Unicode checkmark [✓]");

        let content = "- [✗]  Failed with X mark\n";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Obsidian, None);
        let result = rule.check(&ctx).unwrap();
        assert!(result.is_empty(), "Should skip Unicode X mark [✗]");

        let content = "- [→]  Forwarded with arrow\n";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Obsidian, None);
        let result = rule.check(&ctx).unwrap();
        assert!(result.is_empty(), "Should skip Unicode arrow [→]");
    }

    #[test]
    fn test_flag_extended_checkboxes_in_standard_flavor() {
        // Extended checkboxes should be flagged in Standard flavor (GFM only recognizes [ ], [x], [X])
        let rule = MD064NoMultipleConsecutiveSpaces::new();

        let content = "- [/]  In progress task\n";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        let result = rule.check(&ctx).unwrap();
        assert_eq!(result.len(), 1, "Should flag [/] in Standard flavor");

        let content = "- [-]  Cancelled task\n";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        let result = rule.check(&ctx).unwrap();
        assert_eq!(result.len(), 1, "Should flag [-] in Standard flavor");

        let content = "- [✓]  Unicode checkbox\n";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        let result = rule.check(&ctx).unwrap();
        assert_eq!(result.len(), 1, "Should flag [✓] in Standard flavor");
    }

    #[test]
    fn test_extended_checkboxes_with_indentation() {
        let rule = MD064NoMultipleConsecutiveSpaces::new();

        // Space-indented task list with extended checkbox (Obsidian)
        // 2 spaces is not enough for code block, so this is clearly a list item
        let content = "  - [/]  In progress task\n";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Obsidian, None);
        let result = rule.check(&ctx).unwrap();
        assert!(
            result.is_empty(),
            "Should skip space-indented extended checkbox in Obsidian"
        );

        // 3 spaces - still not a code block
        let content = "   - [-]  Cancelled task\n";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Obsidian, None);
        let result = rule.check(&ctx).unwrap();
        assert!(
            result.is_empty(),
            "Should skip 3-space indented extended checkbox in Obsidian"
        );

        // Tab-indented with list context (parent list makes nested item clear)
        // Without context, a tab-indented line is treated as a code block
        let content = "- Parent item\n\t- [/]  In progress task\n";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Obsidian, None);
        let result = rule.check(&ctx).unwrap();
        assert!(
            result.is_empty(),
            "Should skip tab-indented nested extended checkbox in Obsidian"
        );

        // Space-indented extended checkbox should be flagged in Standard flavor
        let content = "  - [/]  In progress task\n";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        let result = rule.check(&ctx).unwrap();
        assert_eq!(result.len(), 1, "Should flag indented [/] in Standard flavor");

        // 3-space indented extended checkbox should be flagged in Standard flavor
        let content = "   - [-]  Cancelled task\n";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        let result = rule.check(&ctx).unwrap();
        assert_eq!(result.len(), 1, "Should flag 3-space indented [-] in Standard flavor");

        // Tab-indented nested list should be flagged in Standard flavor
        let content = "- Parent item\n\t- [-]  Cancelled task\n";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        let result = rule.check(&ctx).unwrap();
        assert_eq!(
            result.len(),
            1,
            "Should flag tab-indented nested [-] in Standard flavor"
        );

        // Standard checkboxes should still work when indented (both flavors)
        let content = "  - [x]  Completed task\n";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        let result = rule.check(&ctx).unwrap();
        assert!(
            result.is_empty(),
            "Should skip indented standard [x] checkbox in Standard flavor"
        );

        // Tab-indented with list context and standard checkbox
        let content = "- Parent\n\t- [ ]  Pending task\n";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        let result = rule.check(&ctx).unwrap();
        assert!(
            result.is_empty(),
            "Should skip tab-indented nested standard [ ] checkbox"
        );
    }

    #[test]
    fn test_skip_table_without_outer_pipes() {
        let rule = MD064NoMultipleConsecutiveSpaces::new();

        // GFM tables without outer pipes should be skipped
        let content = "Col1      | Col2      | Col3\n";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        let result = rule.check(&ctx).unwrap();
        assert!(result.is_empty());

        // Separator row
        let content = "--------- | --------- | ---------\n";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        let result = rule.check(&ctx).unwrap();
        assert!(result.is_empty());

        // Data row
        let content = "Data1     | Data2     | Data3\n";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        let result = rule.check(&ctx).unwrap();
        assert!(result.is_empty());
    }

    #[test]
    fn test_flag_spaces_in_footnote_content() {
        let rule = MD064NoMultipleConsecutiveSpaces::new();

        // Extra spaces WITHIN footnote text content should be flagged
        let content = "[^1]: Footnote with   extra spaces in content.\n";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        let result = rule.check(&ctx).unwrap();
        assert_eq!(result.len(), 1, "Should flag extra spaces in footnote content");
    }

    #[test]
    fn test_flag_spaces_in_reference_content() {
        let rule = MD064NoMultipleConsecutiveSpaces::new();

        // Extra spaces in the title of a reference link should be flagged
        let content = "[ref]: https://example.com \"Title   with extra spaces\"\n";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        let result = rule.check(&ctx).unwrap();
        assert_eq!(result.len(), 1, "Should flag extra spaces in reference link title");
    }

    // === allow-sentence-double-space tests ===

    #[test]
    fn test_sentence_double_space_disabled_by_default() {
        // Default config should flag double spaces after sentences
        let rule = MD064NoMultipleConsecutiveSpaces::new();
        let content = "First sentence.  Second sentence.";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        let result = rule.check(&ctx).unwrap();
        assert_eq!(result.len(), 1, "Default should flag 2 spaces after period");
    }

    #[test]
    fn test_sentence_double_space_enabled_allows_period() {
        // With allow_sentence_double_space, 2 spaces after period should be OK
        let config = MD064Config {
            allow_sentence_double_space: true,
        };
        let rule = MD064NoMultipleConsecutiveSpaces::from_config_struct(config);

        let content = "First sentence.  Second sentence.";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        let result = rule.check(&ctx).unwrap();
        assert!(result.is_empty(), "Should allow 2 spaces after period");
    }

    #[test]
    fn test_sentence_double_space_enabled_allows_exclamation() {
        let config = MD064Config {
            allow_sentence_double_space: true,
        };
        let rule = MD064NoMultipleConsecutiveSpaces::from_config_struct(config);

        let content = "Wow!  That was great.";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        let result = rule.check(&ctx).unwrap();
        assert!(result.is_empty(), "Should allow 2 spaces after exclamation");
    }

    #[test]
    fn test_sentence_double_space_enabled_allows_question() {
        let config = MD064Config {
            allow_sentence_double_space: true,
        };
        let rule = MD064NoMultipleConsecutiveSpaces::from_config_struct(config);

        let content = "Is this OK?  Yes it is.";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        let result = rule.check(&ctx).unwrap();
        assert!(result.is_empty(), "Should allow 2 spaces after question mark");
    }

    #[test]
    fn test_sentence_double_space_flags_mid_sentence() {
        // Even with allow_sentence_double_space, mid-sentence double spaces should be flagged
        let config = MD064Config {
            allow_sentence_double_space: true,
        };
        let rule = MD064NoMultipleConsecutiveSpaces::from_config_struct(config);

        let content = "Word  word in the middle.";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        let result = rule.check(&ctx).unwrap();
        assert_eq!(result.len(), 1, "Should flag 2 spaces mid-sentence");
    }

    #[test]
    fn test_sentence_double_space_flags_triple_after_period() {
        // 3+ spaces after sentence should still be flagged
        let config = MD064Config {
            allow_sentence_double_space: true,
        };
        let rule = MD064NoMultipleConsecutiveSpaces::from_config_struct(config);

        let content = "First sentence.   Three spaces here.";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        let result = rule.check(&ctx).unwrap();
        assert_eq!(result.len(), 1, "Should flag 3 spaces even after period");
    }

    #[test]
    fn test_sentence_double_space_with_closing_quote() {
        // "Quoted sentence."  Next sentence.
        let config = MD064Config {
            allow_sentence_double_space: true,
        };
        let rule = MD064NoMultipleConsecutiveSpaces::from_config_struct(config);

        let content = r#"He said "Hello."  Then he left."#;
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        let result = rule.check(&ctx).unwrap();
        assert!(result.is_empty(), "Should allow 2 spaces after .\" ");

        // With single quote
        let content = "She said 'Goodbye.'  And she was gone.";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        let result = rule.check(&ctx).unwrap();
        assert!(result.is_empty(), "Should allow 2 spaces after .' ");
    }

    #[test]
    fn test_sentence_double_space_with_curly_quotes() {
        let config = MD064Config {
            allow_sentence_double_space: true,
        };
        let rule = MD064NoMultipleConsecutiveSpaces::from_config_struct(config);

        // Curly double quote: U+201C (") and U+201D (")
        // Build string with actual Unicode characters
        let content = format!(
            "He said {}Hello.{}  Then left.",
            '\u{201C}', // "
            '\u{201D}'  // "
        );
        let ctx = LintContext::new(&content, crate::config::MarkdownFlavor::Standard, None);
        let result = rule.check(&ctx).unwrap();
        assert!(result.is_empty(), "Should allow 2 spaces after curly double quote");

        // Curly single quote: U+2018 (') and U+2019 (')
        let content = format!(
            "She said {}Hi.{}  And left.",
            '\u{2018}', // '
            '\u{2019}'  // '
        );
        let ctx = LintContext::new(&content, crate::config::MarkdownFlavor::Standard, None);
        let result = rule.check(&ctx).unwrap();
        assert!(result.is_empty(), "Should allow 2 spaces after curly single quote");
    }

    #[test]
    fn test_sentence_double_space_with_closing_paren() {
        let config = MD064Config {
            allow_sentence_double_space: true,
        };
        let rule = MD064NoMultipleConsecutiveSpaces::from_config_struct(config);

        let content = "(See reference.)  The next point is.";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        let result = rule.check(&ctx).unwrap();
        assert!(result.is_empty(), "Should allow 2 spaces after .) ");
    }

    #[test]
    fn test_sentence_double_space_with_closing_bracket() {
        let config = MD064Config {
            allow_sentence_double_space: true,
        };
        let rule = MD064NoMultipleConsecutiveSpaces::from_config_struct(config);

        let content = "[Citation needed.]  More text here.";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        let result = rule.check(&ctx).unwrap();
        assert!(result.is_empty(), "Should allow 2 spaces after .] ");
    }

    #[test]
    fn test_sentence_double_space_with_ellipsis() {
        let config = MD064Config {
            allow_sentence_double_space: true,
        };
        let rule = MD064NoMultipleConsecutiveSpaces::from_config_struct(config);

        let content = "He paused...  Then continued.";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        let result = rule.check(&ctx).unwrap();
        assert!(result.is_empty(), "Should allow 2 spaces after ellipsis");
    }

    #[test]
    fn test_sentence_double_space_complex_ending() {
        // Multiple closing punctuation: .")
        let config = MD064Config {
            allow_sentence_double_space: true,
        };
        let rule = MD064NoMultipleConsecutiveSpaces::from_config_struct(config);

        let content = r#"(He said "Yes.")  Then they agreed."#;
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        let result = rule.check(&ctx).unwrap();
        assert!(result.is_empty(), "Should allow 2 spaces after .\") ");
    }

    #[test]
    fn test_sentence_double_space_mixed_content() {
        // Mix of sentence endings and mid-sentence spaces
        let config = MD064Config {
            allow_sentence_double_space: true,
        };
        let rule = MD064NoMultipleConsecutiveSpaces::from_config_struct(config);

        let content = "Good sentence.  Bad  mid-sentence.  Another good one!  OK?  Yes.";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        let result = rule.check(&ctx).unwrap();
        assert_eq!(result.len(), 1, "Should only flag mid-sentence double space");
        assert!(
            result[0].column > 15 && result[0].column < 25,
            "Should flag the 'Bad  mid' double space"
        );
    }

    #[test]
    fn test_sentence_double_space_fix_collapses_to_two() {
        // Fix should collapse 3+ spaces to 2 after sentence, 1 elsewhere
        let config = MD064Config {
            allow_sentence_double_space: true,
        };
        let rule = MD064NoMultipleConsecutiveSpaces::from_config_struct(config);

        let content = "Sentence.   Three spaces here.";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        let fixed = rule.fix(&ctx).unwrap();
        assert_eq!(
            fixed, "Sentence.  Three spaces here.",
            "Should collapse to 2 spaces after sentence"
        );
    }

    #[test]
    fn test_sentence_double_space_fix_collapses_mid_sentence_to_one() {
        // Fix should collapse mid-sentence spaces to 1
        let config = MD064Config {
            allow_sentence_double_space: true,
        };
        let rule = MD064NoMultipleConsecutiveSpaces::from_config_struct(config);

        let content = "Word  word here.";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        let fixed = rule.fix(&ctx).unwrap();
        assert_eq!(fixed, "Word word here.", "Should collapse to 1 space mid-sentence");
    }

    #[test]
    fn test_sentence_double_space_config_kebab_case() {
        let toml_str = r#"
            allow-sentence-double-space = true
        "#;
        let config: MD064Config = toml::from_str(toml_str).unwrap();
        assert!(config.allow_sentence_double_space);
    }

    #[test]
    fn test_sentence_double_space_config_snake_case() {
        let toml_str = r#"
            allow_sentence_double_space = true
        "#;
        let config: MD064Config = toml::from_str(toml_str).unwrap();
        assert!(config.allow_sentence_double_space);
    }

    #[test]
    fn test_sentence_double_space_at_line_start() {
        // Period at very start shouldn't cause issues
        let config = MD064Config {
            allow_sentence_double_space: true,
        };
        let rule = MD064NoMultipleConsecutiveSpaces::from_config_struct(config);

        // This is an edge case - spaces at start are leading indentation
        let content = ".  Text after period at start.";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        // This should not panic
        let _result = rule.check(&ctx).unwrap();
    }

    #[test]
    fn test_sentence_double_space_guillemets() {
        // French-style quotes (guillemets)
        let config = MD064Config {
            allow_sentence_double_space: true,
        };
        let rule = MD064NoMultipleConsecutiveSpaces::from_config_struct(config);

        let content = "Il a dit «Oui.»  Puis il est parti.";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        let result = rule.check(&ctx).unwrap();
        assert!(result.is_empty(), "Should allow 2 spaces after .» (guillemet)");
    }

    #[test]
    fn test_sentence_double_space_multiple_sentences() {
        // Multiple consecutive sentences with double spacing
        let config = MD064Config {
            allow_sentence_double_space: true,
        };
        let rule = MD064NoMultipleConsecutiveSpaces::from_config_struct(config);

        let content = "First.  Second.  Third.  Fourth.";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        let result = rule.check(&ctx).unwrap();
        assert!(result.is_empty(), "Should allow all sentence-ending double spaces");
    }

    #[test]
    fn test_sentence_double_space_abbreviation_detection() {
        // Known abbreviations should NOT be treated as sentence endings
        let config = MD064Config {
            allow_sentence_double_space: true,
        };
        let rule = MD064NoMultipleConsecutiveSpaces::from_config_struct(config);

        // "Dr.  Smith" - Dr. is a known abbreviation, should be flagged
        let content = "Dr.  Smith arrived.";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        let result = rule.check(&ctx).unwrap();
        assert_eq!(result.len(), 1, "Should flag Dr. as abbreviation, not sentence ending");

        // "Prof.  Williams" - Prof. is a known abbreviation
        let content = "Prof.  Williams teaches.";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        let result = rule.check(&ctx).unwrap();
        assert_eq!(result.len(), 1, "Should flag Prof. as abbreviation");

        // "e.g.  this" - e.g. is a known abbreviation
        let content = "Use e.g.  this example.";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        let result = rule.check(&ctx).unwrap();
        assert_eq!(result.len(), 1, "Should flag e.g. as abbreviation");

        // Unknown abbreviation-like words are treated as potential sentence endings
        // "Inc.  Next" - Inc. is NOT in our abbreviation list
        let content = "Acme Inc.  Next company.";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        let result = rule.check(&ctx).unwrap();
        assert!(
            result.is_empty(),
            "Inc. not in abbreviation list, treated as sentence end"
        );
    }

    #[test]
    fn test_sentence_double_space_default_config_has_correct_defaults() {
        let config = MD064Config::default();
        assert!(
            !config.allow_sentence_double_space,
            "Default allow_sentence_double_space should be false"
        );
    }

    #[test]
    fn test_sentence_double_space_from_config_integration() {
        use crate::config::Config;
        use std::collections::BTreeMap;

        let mut config = Config::default();
        let mut values = BTreeMap::new();
        values.insert("allow-sentence-double-space".to_string(), toml::Value::Boolean(true));
        config.rules.insert(
            "MD064".to_string(),
            crate::config::RuleConfig { severity: None, values },
        );

        let rule = MD064NoMultipleConsecutiveSpaces::from_config(&config);

        // Verify the rule uses the loaded config
        let content = "Sentence.  Two spaces OK.  But three   is not.";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        let result = rule.check(&ctx).unwrap();
        assert_eq!(result.len(), 1, "Should only flag the triple spaces");
    }

    #[test]
    fn test_sentence_double_space_after_inline_code() {
        // Issue #345: Sentence ending with inline code should allow double space
        let config = MD064Config {
            allow_sentence_double_space: true,
        };
        let rule = MD064NoMultipleConsecutiveSpaces::from_config_struct(config);

        // Basic case from issue report
        let content = "Hello from `backticks`.  How's it going?";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        let result = rule.check(&ctx).unwrap();
        assert!(
            result.is_empty(),
            "Should allow 2 spaces after inline code ending with period"
        );

        // Multiple inline code spans
        let content = "Use `foo` and `bar`.  Next sentence.";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        let result = rule.check(&ctx).unwrap();
        assert!(result.is_empty(), "Should allow 2 spaces after code at end of sentence");

        // With exclamation mark
        let content = "The `code` worked!  Celebrate.";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        let result = rule.check(&ctx).unwrap();
        assert!(result.is_empty(), "Should allow 2 spaces after code with exclamation");

        // With question mark
        let content = "Is `null` falsy?  Yes.";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        let result = rule.check(&ctx).unwrap();
        assert!(result.is_empty(), "Should allow 2 spaces after code with question mark");

        // Inline code mid-sentence (not at end) - double space SHOULD be flagged
        let content = "The `code`  is here.";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        let result = rule.check(&ctx).unwrap();
        assert_eq!(result.len(), 1, "Should flag 2 spaces after code mid-sentence");
    }

    #[test]
    fn test_sentence_double_space_code_with_closing_punctuation() {
        // Inline code followed by period in parentheses
        let config = MD064Config {
            allow_sentence_double_space: true,
        };
        let rule = MD064NoMultipleConsecutiveSpaces::from_config_struct(config);

        // Code in parentheses
        let content = "(see `example`).  Next sentence.";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        let result = rule.check(&ctx).unwrap();
        assert!(result.is_empty(), "Should allow 2 spaces after code in parentheses");

        // Code in quotes
        let content = "He said \"use `code`\".  Then left.";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        let result = rule.check(&ctx).unwrap();
        assert!(result.is_empty(), "Should allow 2 spaces after code in quotes");
    }

    #[test]
    fn test_sentence_double_space_after_emphasis() {
        // Sentence ending with emphasis should allow double space
        let config = MD064Config {
            allow_sentence_double_space: true,
        };
        let rule = MD064NoMultipleConsecutiveSpaces::from_config_struct(config);

        // Asterisk emphasis
        let content = "The word is *important*.  Next sentence.";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        let result = rule.check(&ctx).unwrap();
        assert!(result.is_empty(), "Should allow 2 spaces after emphasis");

        // Underscore emphasis
        let content = "The word is _important_.  Next sentence.";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        let result = rule.check(&ctx).unwrap();
        assert!(result.is_empty(), "Should allow 2 spaces after underscore emphasis");

        // Bold (asterisk)
        let content = "The word is **critical**.  Next sentence.";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        let result = rule.check(&ctx).unwrap();
        assert!(result.is_empty(), "Should allow 2 spaces after bold");

        // Bold (underscore)
        let content = "The word is __critical__.  Next sentence.";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        let result = rule.check(&ctx).unwrap();
        assert!(result.is_empty(), "Should allow 2 spaces after underscore bold");
    }

    #[test]
    fn test_sentence_double_space_after_strikethrough() {
        // Sentence ending with strikethrough should allow double space
        let config = MD064Config {
            allow_sentence_double_space: true,
        };
        let rule = MD064NoMultipleConsecutiveSpaces::from_config_struct(config);

        let content = "This is ~~wrong~~.  Next sentence.";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        let result = rule.check(&ctx).unwrap();
        assert!(result.is_empty(), "Should allow 2 spaces after strikethrough");

        // With exclamation
        let content = "That was ~~bad~~!  Learn from it.";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        let result = rule.check(&ctx).unwrap();
        assert!(
            result.is_empty(),
            "Should allow 2 spaces after strikethrough with exclamation"
        );
    }

    #[test]
    fn test_sentence_double_space_after_extended_markdown() {
        // Extended markdown syntax (highlight, superscript)
        let config = MD064Config {
            allow_sentence_double_space: true,
        };
        let rule = MD064NoMultipleConsecutiveSpaces::from_config_struct(config);

        // Highlight syntax
        let content = "This is ==highlighted==.  Next sentence.";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        let result = rule.check(&ctx).unwrap();
        assert!(result.is_empty(), "Should allow 2 spaces after highlight");

        // Superscript
        let content = "E equals mc^2^.  Einstein said.";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        let result = rule.check(&ctx).unwrap();
        assert!(result.is_empty(), "Should allow 2 spaces after superscript");
    }

    #[test]
    fn test_inline_config_allow_sentence_double_space() {
        // Issue #364: Inline configure-file comments should work
        // Tests the automatic inline config support via Config::merge_with_inline_config

        let rule = MD064NoMultipleConsecutiveSpaces::new(); // Default config (disabled)

        // Without inline config, should flag
        let content = "`<svg>`.  Fortunately";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        let result = rule.check(&ctx).unwrap();
        assert_eq!(result.len(), 1, "Default config should flag double spaces");

        // With inline config, should allow
        // Simulate engine behavior: parse inline config, merge with base config, recreate rule
        let content = r#"<!-- rumdl-configure-file { "MD064": { "allow-sentence-double-space": true } } -->

`<svg>`.  Fortunately"#;
        let inline_config = crate::inline_config::InlineConfig::from_content(content);
        let base_config = crate::config::Config::default();
        let merged_config = base_config.merge_with_inline_config(&inline_config);
        let effective_rule = MD064NoMultipleConsecutiveSpaces::from_config(&merged_config);
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        let result = effective_rule.check(&ctx).unwrap();
        assert!(
            result.is_empty(),
            "Inline config should allow double spaces after sentence"
        );

        // Also test with markdownlint prefix
        let content = r#"<!-- markdownlint-configure-file { "MD064": { "allow-sentence-double-space": true } } -->

**scalable**.  Pick"#;
        let inline_config = crate::inline_config::InlineConfig::from_content(content);
        let merged_config = base_config.merge_with_inline_config(&inline_config);
        let effective_rule = MD064NoMultipleConsecutiveSpaces::from_config(&merged_config);
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        let result = effective_rule.check(&ctx).unwrap();
        assert!(result.is_empty(), "Inline config with markdownlint prefix should work");
    }

    #[test]
    fn test_inline_config_allow_sentence_double_space_issue_364() {
        // Full test case from issue #364
        // Tests the automatic inline config support via Config::merge_with_inline_config

        let content = r#"<!-- rumdl-configure-file { "MD064": { "allow-sentence-double-space": true } } -->

# Title

what the font size is for the toplevel `<svg>`.  Fortunately, librsvg

And here is where I want to say, SVG documents are **scalable**.  Pick

That's right, no `width`, no `height`, no `viewBox`.  There is no easy

**SVG documents are scalable**.  That's their whole reason for being!"#;

        // Simulate engine behavior: parse inline config, merge with base config, recreate rule
        let inline_config = crate::inline_config::InlineConfig::from_content(content);
        let base_config = crate::config::Config::default();
        let merged_config = base_config.merge_with_inline_config(&inline_config);
        let effective_rule = MD064NoMultipleConsecutiveSpaces::from_config(&merged_config);
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        let result = effective_rule.check(&ctx).unwrap();
        assert!(
            result.is_empty(),
            "Issue #364: All sentence-ending double spaces should be allowed with inline config. Found {} warnings",
            result.len()
        );
    }

    #[test]
    fn test_indented_reference_link_not_flagged() {
        // Bug: Reference link definitions with leading whitespace had incorrect
        // colon_pos calculation (leading whitespace count was always 0)
        let rule = MD064NoMultipleConsecutiveSpaces::default();

        // Indented reference link with extra spaces after ]: should not be flagged
        let content = "   [label]:  https://example.com";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        let result = rule.check(&ctx).unwrap();
        assert!(
            result.is_empty(),
            "Indented reference link definitions should not be flagged, got: {:?}",
            result
                .iter()
                .map(|w| format!("col={}: {}", w.column, &w.message))
                .collect::<Vec<_>>()
        );

        // Non-indented reference link should still not be flagged
        let content = "[label]:  https://example.com";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        let result = rule.check(&ctx).unwrap();
        assert!(result.is_empty(), "Reference link definitions should not be flagged");
    }

    #[test]
    fn test_pre_block_with_blank_line_not_flagged() {
        // Content inside <pre> must not be flagged even when a blank line
        // precedes the flagged text within the block (CommonMark §4.6 Type 1).
        let rule = MD064NoMultipleConsecutiveSpaces::default();

        let content = "# Heading\n\n<pre>\n\nhello  world\n</pre>\n";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        let result = rule.check(&ctx).unwrap();
        assert!(
            result.is_empty(),
            "MD064 must not fire inside <pre> when a blank line precedes the content, got: {result:?}"
        );
    }

    #[test]
    fn test_textarea_block_with_blank_line_not_flagged() {
        // <textarea> is a CommonMark Type-1 block — blank lines inside it
        // must not terminate the HTML block or expose content to lint rules.
        let rule = MD064NoMultipleConsecutiveSpaces::default();

        let content = "<textarea>\n\ninner  content\n</textarea>\n";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        let result = rule.check(&ctx).unwrap();
        assert!(
            result.is_empty(),
            "MD064 must not fire inside <textarea> when a blank line precedes the content, got: {result:?}"
        );
    }

    #[test]
    fn test_div_with_blank_line_content_is_flagged() {
        // <div> is a Type-6 block — it terminates at the first blank line,
        // so content after a blank line inside <div> is treated as normal
        // Markdown text and must be flagged by MD064.
        let rule = MD064NoMultipleConsecutiveSpaces::default();

        let content = "<div>\ninner\n\nafter  blank\n</div>\n";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        let result = rule.check(&ctx).unwrap();
        assert!(
            !result.is_empty(),
            "MD064 must fire on content after a blank line inside a <div> block"
        );
    }

    #[test]
    fn test_column_aligned_list_not_flagged_cdk_template() {
        // The "Useful commands" block produced by `cdk init` has every item
        // column-aligned with a multi-space gap before the description. The
        // alignment is intentional, so MD064 must report zero issues — and
        // therefore offer no destructive partial fix.
        let rule = MD064NoMultipleConsecutiveSpaces::default();

        let content = "# Useful commands\n\n\
            - `cdk ls`          list all stacks in the app\n\
            - `cdk synth`       emits the synthesized CloudFormation template\n\
            - `cdk deploy`      deploy this stack to your default AWS account/region\n\
            - `cdk diff`        compare deployed stack with current state\n\
            - `cdk docs`        open CDK documentation\n";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        let result = rule.check(&ctx).unwrap();
        assert!(
            result.is_empty(),
            "Column-aligned list (cdk init template) must not be flagged, got: {:?}",
            result
                .iter()
                .map(|w| format!("L{}C{}: {}", w.line, w.column, w.message))
                .collect::<Vec<_>>()
        );

        // And `fix` must leave the file unchanged.
        let fixed = rule.fix(&ctx).unwrap();
        assert_eq!(fixed, content, "fix must not collapse intentional alignment");
    }

    #[test]
    fn test_column_aligned_two_item_list_not_flagged() {
        // Smallest qualifying case: two items, both with internal multi-space.
        let rule = MD064NoMultipleConsecutiveSpaces::default();

        let content = "- `a`     alpha\n- `b`     beta\n";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        let result = rule.check(&ctx).unwrap();
        assert!(
            result.is_empty(),
            "Two-item aligned list must not be flagged, got: {result:?}"
        );
    }

    #[test]
    fn test_partially_aligned_list_is_flagged_normally() {
        // When alignment is broken (one item has no internal multi-space), the
        // block is not column-aligned and MD064 must fire on the items that
        // actually contain extra spaces.
        let rule = MD064NoMultipleConsecutiveSpaces::default();

        let content = "- `a`     alpha\n- short\n- `c`     gamma\n";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        let result = rule.check(&ctx).unwrap();
        assert_eq!(
            result.len(),
            2,
            "Items with multi-space must be flagged when the surrounding list is not uniformly aligned, got: {result:?}"
        );
    }

    #[test]
    fn test_single_item_list_with_multi_space_still_flagged() {
        // A list with only one item provides no surrounding alignment context,
        // so the multi-space run is treated as an ordinary violation.
        let rule = MD064NoMultipleConsecutiveSpaces::default();

        let content = "- `a`     alpha\n";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        let result = rule.check(&ctx).unwrap();
        assert_eq!(
            result.len(),
            1,
            "Single-item list must still be flagged, got: {result:?}"
        );
    }

    #[test]
    fn test_nested_aligned_lists_evaluated_independently() {
        // Both the outer and the inner list are column-aligned; both must be
        // skipped without one masking the other.
        let rule = MD064NoMultipleConsecutiveSpaces::default();

        let content = "- `cmd1`     outer one\n\
            \x20\x20- `sub-a`   inner one\n\
            \x20\x20- `sub-b`   inner two\n\
            - `cmd2`     outer two\n";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        let result = rule.check(&ctx).unwrap();
        assert!(
            result.is_empty(),
            "Nested column-aligned lists must not be flagged, got: {result:?}"
        );
    }

    #[test]
    fn test_siblings_at_a_different_indent_share_the_alignment_exemption() {
        // Items whose markers sit at different indents are still one list, so
        // an aligned pair is exempt together; and a sibling of the parent is
        // not judged with the nested list that happens to share its column.
        let rule = MD064NoMultipleConsecutiveSpaces::default();
        for content in [
            " - `cmd1`   one\n  - `cmd2`   two\n",
            " - `cmd1`   one\n   - sub\n  - `cmd2`   two\n",
        ] {
            let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
            let result = rule.check(&ctx).unwrap();
            assert!(result.is_empty(), "{content:?}: {result:?}");
            assert_eq!(
                rule.fix(&ctx).unwrap(),
                content,
                "{content:?}: fix must keep the alignment"
            );
        }

        // Positive controls: with one sibling unaligned the pair is not an
        // aligned list, so the aligned sibling is reported; and a padded
        // nested item is a one-item list of its own, reported alone, rather
        // than an aligned pair with the sibling that shares its column.
        for (content, line) in [
            (" - `cmd1`   one\n  - `cmd2` two\n", 1),
            (" - `cmd1`   one\n   - `sub`   padded\n  - `cmd2`   two\n", 2),
        ] {
            let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
            let result = rule.check(&ctx).unwrap();
            assert_eq!(result.len(), 1, "{content:?}: {result:?}");
            assert_eq!(result[0].line, line, "{content:?}");
        }

        // Inside a blockquote the columns count from the quote's content, so
        // the indent before the `>` does not turn a nested item into a
        // sibling: parent and child are one-item lists, each reported.
        let content = " > - `a`   parent\n>   - `b`   child\n";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        let result = rule.check(&ctx).unwrap();
        assert_eq!(result.len(), 2, "{content:?}: {result:?}");
        assert_eq!(result[0].line, 1, "{content:?}");
        assert_eq!(result[1].line, 2, "{content:?}");
        // The same pair with the quote markers aligned is the same structure.
        let content = "> - `a`   parent\n>   - `b`   child\n";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        let result = rule.check(&ctx).unwrap();
        assert_eq!(result.len(), 2, "{content:?}: {result:?}");

        // A `>` left of the item's content starts a blockquote outside the
        // item, so `c` is not a sibling of `b` in the quote inside `p`, even
        // though both markers sit at the same column inside their quotes.
        let content = "- p\n  >- `b`   x\n>- `c`   x\n";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        let result = rule.check(&ctx).unwrap();
        assert_eq!(result.len(), 2, "{content:?}: {result:?}");
        assert_eq!(result[0].line, 2, "{content:?}");
        assert_eq!(result[1].line, 3, "{content:?}");

        // A fence at column 0 ends `p` and its list, so the blockquote after
        // it is not inside `p`: `b` and `c` are siblings in one quote, an
        // aligned pair. Without the fence the quote is inside `p`, and the
        // `>` at column 0 starts another one, so each item is judged alone.
        let content = "- p\n```\n```\n  > - `b`   x\n  lazy\n> - `c`   x\n";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        let result = rule.check(&ctx).unwrap();
        assert!(result.is_empty(), "{content:?}: {result:?}");
        assert_eq!(
            rule.fix(&ctx).unwrap(),
            content,
            "{content:?}: fix must keep the alignment"
        );
        let content = "- p\n  > - `b`   x\n  lazy\n> - `c`   x\n";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        let result = rule.check(&ctx).unwrap();
        assert_eq!(result.len(), 2, "{content:?}: {result:?}");
        assert_eq!(result[0].line, 2, "{content:?}");
        assert_eq!(result[1].line, 4, "{content:?}");
    }

    #[test]
    fn test_unaligned_nested_item_does_not_break_parent_alignment() {
        // The parent list is column-aligned; a nested child with no alignment
        // gap of its own belongs to a different list and must not disqualify
        // the parent items, whose spacing stays intentional. Space and tab
        // nesting behave the same.
        let rule = MD064NoMultipleConsecutiveSpaces::default();
        for (label, content) in [
            (
                "spaces",
                "- first  aligned\n- second  aligned\n- third  aligned\n  1. child\n",
            ),
            (
                "tab",
                "- first  aligned\n- second  aligned\n- third  aligned\n\t1. child\n",
            ),
        ] {
            let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
            let result = rule.check(&ctx).unwrap();
            assert!(result.is_empty(), "{label}: {result:?}");
            assert_eq!(rule.fix(&ctx).unwrap(), content, "{label}: fix must keep the alignment");
        }

        // Positive control: the child itself carries a multi-space run and is
        // a single-item list, so it is reported while the parent items are not.
        let content = "- first  aligned\n- second  aligned\n  1. child  padded\n";
        let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
        let result = rule.check(&ctx).unwrap();
        assert_eq!(result.len(), 1, "{result:?}");
        assert_eq!(result[0].line, 3);

        // Parent content between two nested lists (an HTML comment, a bare
        // `>` opening a blockquote) ends the first, so a padded single item
        // after it is its own list and gets no exemption from the aligned
        // pair before it.
        for (content, line) in [
            (
                "- parent\n  - a  aligned\n  - b  aligned\n  <!-- parent block -->\n  - only  padded\n- next\n",
                5,
            ),
            (
                "- parent\n  - a  aligned\n  - b  aligned\n  >\n  - only  padded\n- next\n",
                5,
            ),
            (
                "- parent\n  - a  aligned\n  - b  aligned\n    >\n  parent\n  - only  padded\n- next\n",
                6,
            ),
        ] {
            let ctx = LintContext::new(content, crate::config::MarkdownFlavor::Standard, None);
            let result = rule.check(&ctx).unwrap();
            assert_eq!(result.len(), 1, "{content:?}: {result:?}");
            assert_eq!(result[0].line, line, "{content:?}");
        }
    }
}