Add support for 4-bit foreground colors in test utilities

4-bit color ANSI escape sequences look like: ^[1;31m

For foreground, they are the 8 color codes 30-37 and the 8 bright color codes 90-97

Delta does not actually emit them (they are converted to
ansi_term::Color::Fixed(n) by to_ansi_color), but git does by default,
so they are needed for testing delta's handling of colors received
from git.

1 files changed, 72 insertions, 13 deletions

diff --git a/src/tests/ansi_test_utils.rs b/src/tests/ansi_test_utils.rs
index 6e20fb1c..33ee5d0f 100644
--- a/src/tests/ansi_test_utils.rs
+++ b/src/tests/ansi_test_utils.rs
@@ -7,27 +7,38 @@ pub mod ansi_test_utils {
     use crate::paint;
     use crate::style::Style;
 
-    pub fn has_foreground_color(string: &str, color: ansi_term::Color) -> bool {
-        let style = ansi_term::Style::default().fg(color);
-        string.starts_with(&style.prefix().to_string())
+    pub fn assert_line_has_foreground_color(
+        output: &str,
+        line_number: usize,
+        expected_prefix: &str,
+        expected_style: &str,
+        config: &Config,
+    ) {
+        _assert_line_has_foreground_color(
+            output,
+            line_number,
+            expected_prefix,
+            expected_style,
+            config,
+            false,
+        );
     }
 
-    pub fn assert_line_has_foreground_color(
+    pub fn assert_line_has_4_bit_foreground_color(
         output: &str,
         line_number: usize,
         expected_prefix: &str,
         expected_style: &str,
         config: &Config,
     ) {
-        let line = output.lines().nth(line_number).unwrap();
-        assert!(strip_ansi_codes(line).starts_with(expected_prefix));
-        assert!(has_foreground_color(
-            line,
-            Style::from_str(expected_style, None, None, None, config.true_color, false)
-                .ansi_term_style
-                .foreground
-                .unwrap()
-        ));
+        _assert_line_has_foreground_color(
+            output,
+            line_number,
+            expected_prefix,
+            expected_style,
+            config,
+            true,
+        );
     }
 
     pub fn assert_line_has_no_color(output: &str, line_number: usize, expected_prefix: &str) {
@@ -105,4 +116,52 @@ pub mod ansi_test_utils {
         );
         output_buffer
     }
+
+    fn has_foreground_color(string: &str, color: ansi_term::Color, _4_bit_color: bool) -> bool {
+        let color = if _4_bit_color {
+            ansi_term_fixed_foreground_to_4_bit_color(color)
+        } else {
+            color
+        };
+        let style = ansi_term::Style::default().fg(color);
+        string.starts_with(&style.prefix().to_string())
+    }
+
+    fn _assert_line_has_foreground_color(
+        output: &str,
+        line_number: usize,
+        expected_prefix: &str,
+        expected_style: &str,
+        config: &Config,
+        _4_bit_color: bool,
+    ) {
+        let line = output.lines().nth(line_number).unwrap();
+        assert!(strip_ansi_codes(line).starts_with(expected_prefix));
+        assert!(has_foreground_color(
+            line,
+            Style::from_str(expected_style, None, None, None, config.true_color, false)
+                .ansi_term_style
+                .foreground
+                .unwrap(),
+            _4_bit_color
+        ));
+    }
+
+    fn ansi_term_fixed_foreground_to_4_bit_color(color: ansi_term::Color) -> ansi_term::Color {
+        match color {
+            ansi_term::Color::Fixed(30) => ansi_term::Color::Black,
+            ansi_term::Color::Fixed(31) => ansi_term::Color::Red,
+            ansi_term::Color::Fixed(32) => ansi_term::Color::Green,
+            ansi_term::Color::Fixed(33) => ansi_term::Color::Yellow,
+            ansi_term::Color::Fixed(34) => ansi_term::Color::Blue,
+            ansi_term::Color::Fixed(35) => ansi_term::Color::Purple,
+            ansi_term::Color::Fixed(36) => ansi_term::Color::Cyan,
+            ansi_term::Color::Fixed(37) => ansi_term::Color::White,
+            color => panic!(
+                "Invalid 4-bit color: {:?}. \
+                 (Add bright color entries to this map if needed for tests.",
+                color
+            ),
+        }
+    }
 }