clex_gen 0.4.0

A generator for clex language
Documentation 
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/// Test that error messages include span information with ergonomic formatting
/// This test validates the issue fix for "Better error message for clex consumption"
use clex_gen::generator;

#[test]
fn test_lexer_error_includes_span() {
    let input = "'unclosed string";
    let result = generator(input.to_string());
    assert!(result.is_err());
    let error_message = result.unwrap_err().to_string();

    // Should include position information in cargo/clippy style
    assert!(error_message.contains("input:"));
    assert!(error_message.contains("0.."));

    // Should still include the error description
    assert!(error_message.contains("expected closing single quote"));
}

#[test]
fn test_parser_error_includes_span() {
    let input = "N[1, 2";
    let result = generator(input.to_string());
    assert!(result.is_err());
    let error_message = result.unwrap_err().to_string();

    // Should include position information
    assert!(error_message.contains("input:"));

    // Should still include the error description
    assert!(error_message.contains("expected closing square bracket"));
}

#[test]
fn test_invalid_charset_error_includes_span() {
    let input = "@CH_INVALID@";
    let result = generator(input.to_string());
    assert!(result.is_err());
    let error_message = result.unwrap_err().to_string();

    // Should include position information
    assert!(error_message.contains("input:"));
    assert!(error_message.contains("0.."));

    // Should still include the error description
    assert!(error_message.contains("invalid character set"));
}

#[test]
fn test_multiple_errors_have_different_positions() {
    let test_cases = [
        "'hello",    // Position starts at 0
        "N '  ",     // Position starts at 2
        "N N '    ", // Position starts at 4
    ];

    for (i, input) in test_cases.iter().enumerate() {
        let result = generator(input.to_string());
        assert!(result.is_err(), "Test case {} should error", i);
        let error_message = result.unwrap_err().to_string();

        // Each should have position information with source context
        assert!(error_message.contains("input:"));
        assert!(error_message.contains("|")); // Should have visual pointer
    }
}

#[test]
fn test_unclosed_non_capturing_group_error() {
    let input = "(?:N";
    let result = generator(input.to_string());
    assert!(result.is_err());
    let error_message = result.unwrap_err().to_string();

    // Should include position information
    assert!(error_message.contains("input:"));

    // Should include the error description
    assert!(error_message.contains("non-capturing group"));
}

#[test]
fn test_missing_colon_after_question_mark() {
    let input = "N ?";
    let result = generator(input.to_string());
    assert!(result.is_err());
    let error_message = result.unwrap_err().to_string();

    // Should include position information
    assert!(error_message.contains("input:"));

    // Should include the error description
    assert!(error_message.contains("expected colon"));
}

#[test]
fn test_negative_group_number_error() {
    let input = "N{\\0}";
    let result = generator(input.to_string());
    assert!(result.is_err());
    let error_message = result.unwrap_err().to_string();

    // Should include position information
    assert!(error_message.contains("input:"));

    // Should include the error description with helpful message
    assert!(error_message.contains("group number must be positive"));
}

#[test]
fn test_error_format_has_visual_pointer() {
    let input = "'test";
    let result = generator(input.to_string());
    assert!(result.is_err());
    let error_message = result.unwrap_err().to_string();

    // Should have the cargo/clippy style visual pointer
    assert!(error_message.contains("^")); // Caret pointer
    assert!(error_message.contains("|")); // Line separator
    assert!(error_message.contains("error:")); // Error prefix
}