termdiff 4.2.1

Write a diff with color codes to a string
Documentation 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181

//! Edge-case tests for unusual inputs and boundary conditions.
//!
//! Covers trailing newlines, CRLF, Unicode, empty/identical inputs, and
//! single-character diffs.

use std::borrow::Cow;

use termdiff::{DrawDiff, Theme};

fn render(old: &str, new: &str, theme: &dyn Theme) -> String {
    format!("{}", DrawDiff::new(old, new, theme))
}

// ---------------------------------------------------------------------------
// Trailing newline differences
// ---------------------------------------------------------------------------

#[test]
#[cfg(feature = "arrows")]
fn trailing_nl_old_has_newline_new_does_not() {
    let theme = termdiff::ArrowsTheme::default();
    let output = render("line\n", "line", &theme);
    assert!(
        output.contains('␊'),
        "Expected trailing LF marker, got:\\n{}",
        output
    );
}

#[test]
#[cfg(feature = "arrows")]
fn trailing_nl_new_has_newline_old_does_not() {
    let theme = termdiff::ArrowsTheme::default();
    let output = render("line", "line\n", &theme);
    assert!(
        output.contains('␊'),
        "Expected trailing LF marker, got:\\n{}",
        output
    );
}

#[test]
#[cfg(feature = "arrows")]
fn trailing_nl_on_completely_different_lines() {
    let theme = termdiff::ArrowsTheme::default();
    let output = render("hello\n", "world", &theme);

    assert!(output.contains('␊'));
    assert!(output.contains("<hello"));
    assert!(output.contains(">world"));
}

#[test]
#[cfg(feature = "arrows")]
fn trailing_nl_multiline_only_difference() {
    let old = "line1\nline2\nline3\n";
    let new = "line1\nline2\nline3";
    let theme = termdiff::ArrowsTheme::default();
    let output = render(old, new, &theme);

    // The first two lines should be unchanged
    assert!(output.contains(" line1\n"));
    assert!(output.contains(" line2\n"));
    // The trailing newline difference should be shown with the marker
    assert!(output.contains('␊'));
}

#[test]
#[cfg(feature = "arrows")]
fn trailing_nl_on_different_last_lines() {
    let theme = termdiff::ArrowsTheme::default();
    let output = render("apple\norange\n", "apple\nbanana", &theme);

    assert!(
        output.contains('␊'),
        "Expected trailing LF marker when old has trailing newline and new does not"
    );
}

/// Verify the exact output when the only difference is a trailing newline
/// on a single-line input.
#[test]
#[cfg(feature = "arrows")]
fn trailing_nl_exact_output() {
    let theme = termdiff::ArrowsTheme::default();
    let output = render("a\nb\nc", "a\nc\n", &theme);

    assert_eq!(
        output,
        "\
< left / > right
 a
<b
<c
>c␊
",
    );
}

#[test]
fn custom_trailing_lf_marker() {
    #[derive(Debug)]
    struct CustomMarkerTheme;

    impl Theme for CustomMarkerTheme {
        fn equal_prefix<'a>(&self) -> Cow<'a, str> {
            " ".into()
        }
        fn delete_prefix<'a>(&self) -> Cow<'a, str> {
            "<".into()
        }
        fn insert_prefix<'a>(&self) -> Cow<'a, str> {
            ">".into()
        }
        fn header<'a>(&self) -> Cow<'a, str> {
            "HEADER\n".into()
        }
        fn trailing_lf_marker<'a>(&self) -> Cow<'a, str> {
            "[NEWLINE]".into()
        }
    }

    let output = render("line\n", "line", &CustomMarkerTheme);
    assert!(output.contains("line[NEWLINE]"));
}

// ---------------------------------------------------------------------------
// CRLF
// ---------------------------------------------------------------------------

#[test]
#[cfg(feature = "arrows")]
fn crlf_produces_visible_carriage_return() {
    let theme = termdiff::ArrowsTheme::default();
    let output = render("line\r\n", "line", &theme);

    // The library treats \n as the line separator, leaving \r as line content
    assert!(
        output.contains('\r'),
        "Expected carriage return in diff output for CRLF input"
    );
}

// ---------------------------------------------------------------------------
// Unicode
// ---------------------------------------------------------------------------

#[test]
#[cfg(feature = "arrows")]
fn unicode_handled_correctly() {
    let theme = termdiff::ArrowsTheme::default();
    let output = render("héllo\nwörld", "héllo\nwörld!", &theme);

    assert!(output.contains(" héllo\n"));
    assert!(output.contains("<wörld"));
    assert!(output.contains(">wörld!"));
}

// ---------------------------------------------------------------------------
// Minimal inputs
// ---------------------------------------------------------------------------

#[test]
#[cfg(feature = "arrows")]
fn single_char_replacement() {
    let theme = termdiff::ArrowsTheme::default();
    let output = render("a", "b", &theme);

    assert!(output.contains("<a"));
    assert!(output.contains(">b"));
}

#[test]
#[cfg(feature = "arrows")]
fn whitespace_only_difference() {
    let theme = termdiff::ArrowsTheme::default();
    let output = render("text with spaces", "text  with  spaces", &theme);

    assert!(output.contains("<text with spaces"));
    assert!(output.contains(">text  with  spaces"));
}