Move strip_ansi_codes to test module and enable highlighting in all t…

…ests

Changes:
- Moved strip_ansi_codes() from public API to test-only helper
- Made highlight::tests module public for cross-module test access
- Added render_for_snapshot() helper that enables highlighting and strips ANSI
- Updated all 21 render_code_frame() calls in tests to use render_for_snapshot()

Result:
- All tests now verify highlighting doesn't break formatting
- No snapshot changes required (proving highlighting works correctly!)
- All 31 tests pass

This ensures that every code frame rendering path is tested with
highlighting enabled, giving us confidence that the feature works
correctly across all edge cases.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <[email protected]>

crates/next-code-frame/src/highlight.rs

@@ -137,22 +137,14 @@ pub fn extract_highlights(source: &str) -> Vec<LineHighlight> {
     // Lex all tokens and extract style markers
     let mut markers = Vec::new();
 
-    loop {
-        match lexer.next() {
-            Some(token) => {
-                if token.token == Token::Eof {
-                    break;
-                }
+    for token in lexer {
+        if token.token == Token::Eof {
+            break;
+        }
 
-                // Classify token and add markers
-                if let Some(token_type) = classify_token(&token.token) {
-                    add_token_markers(&mut markers, token.span, token_type);
-                }
-            }
-            None => {
-                // End of input
-                break;
-            }
+        // Classify token and add markers
+        if let Some(token_type) = classify_token(&token.token) {
+            add_token_markers(&mut markers, token.span, token_type);
         }
     }
 
@@ -435,35 +427,35 @@ pub fn apply_line_highlights(
     result
 }
 
-/// Strip ANSI escape codes from a string
-/// This is useful for testing to verify content without color codes
-pub fn strip_ansi_codes(s: &str) -> String {
-    let mut result = String::with_capacity(s.len());
-    let mut chars = s.chars();
-
-    while let Some(ch) = chars.next() {
-        if ch == '\x1b' {
-            // Skip ANSI escape sequence
-            // Format: ESC [ <params> <command>
-            if chars.next() == Some('[') {
-                // Skip until we find a letter (the command character)
-                for ch in chars.by_ref() {
-                    if ch.is_alphabetic() {
-                        break;
+#[cfg(test)]
+pub mod tests {
+    use super::*;
+
+    /// Strip ANSI escape codes from a string
+    /// This is useful for testing to verify content without color codes
+    pub fn strip_ansi_codes(s: &str) -> String {
+        let mut result = String::with_capacity(s.len());
+        let mut chars = s.chars();
+
+        while let Some(ch) = chars.next() {
+            if ch == '\x1b' {
+                // Skip ANSI escape sequence
+                // Format: ESC [ <params> <command>
+                if chars.next() == Some('[') {
+                    // Skip until we find a letter (the command character)
+                    for ch in chars.by_ref() {
+                        if ch.is_alphabetic() {
+                            break;
+                        }
                     }
                 }
+            } else {
+                result.push(ch);
             }
-        } else {
-            result.push(ch);
         }
-    }
-
-    result
-}
 
-#[cfg(test)]
-mod tests {
-    use super::*;
+        result
+    }
 
     #[test]
     fn test_extract_highlights_basic() {

crates/next-code-frame/src/tests.rs

@@ -1,9 +1,24 @@
 use insta::assert_snapshot;
 
 use crate::{
-    CodeFrameLocation, CodeFrameOptions, Location, highlight::strip_ansi_codes, render_code_frame,
+    CodeFrameLocation, CodeFrameOptions, Location, highlight::tests::strip_ansi_codes,
+    render_code_frame,
 };
 
+/// Helper function to render code frame with highlighting enabled and ANSI codes stripped
+/// This ensures highlighting doesn't break the basic formatting
+fn render_for_snapshot(
+    source: &str,
+    location: &CodeFrameLocation,
+    options: &CodeFrameOptions,
+) -> Result<String, anyhow::Error> {
+    let mut opts_with_highlighting = options.clone();
+    opts_with_highlighting.highlight_code = true;
+
+    let result = render_code_frame(source, location, &opts_with_highlighting)?;
+    Ok(strip_ansi_codes(&result))
+}
+
 #[test]
 fn test_simple_single_line_error() {
     let source = "console.log('hello')";
@@ -17,7 +32,7 @@ fn test_simple_single_line_error() {
         ..Default::default()
     };
 
-    let result = render_code_frame(source, &location, &options).unwrap();
+    let result = render_for_snapshot(source, &location, &options).unwrap();
     assert_snapshot!(result, @r"
     > 1 | console.log('hello')
         | ^
@@ -37,7 +52,7 @@ fn test_empty_source() {
         ..Default::default()
     };
 
-    let result = render_code_frame(source, &location, &options).unwrap();
+    let result = render_for_snapshot(source, &location, &options).unwrap();
     assert_snapshot!(result, @"");
 }
 
@@ -57,7 +72,7 @@ fn test_invalid_line_number() {
         ..Default::default()
     };
 
-    let result = render_code_frame(source, &location, &options).unwrap();
+    let result = render_for_snapshot(source, &location, &options).unwrap();
     assert_snapshot!(result, @"");
 }
 
@@ -77,7 +92,7 @@ fn test_multiline_error() {
         ..Default::default()
     };
 
-    let result = render_code_frame(source, &location, &options).unwrap();
+    let result = render_for_snapshot(source, &location, &options).unwrap();
     assert_snapshot!(result, @r"
       1 | function test() {
     > 2 |   console.log('hello')
@@ -105,7 +120,7 @@ fn test_multiline_error_with_message() {
         ..Default::default()
     };
 
-    let result = render_code_frame(source, &location, &options).unwrap();
+    let result = render_for_snapshot(source, &location, &options).unwrap();
     assert_snapshot!(result, @r"
       1 | function test() {
     > 2 |   console.log('hello')
@@ -130,7 +145,7 @@ fn test_with_message() {
         ..Default::default()
     };
 
-    let result = render_code_frame(source, &location, &options).unwrap();
+    let result = render_for_snapshot(source, &location, &options).unwrap();
     assert_snapshot!(result, @r"
     > 1 | const x = 1
         |       ^ Expected semicolon
@@ -157,7 +172,7 @@ fn test_long_line_single_error() {
         ..Default::default()
     };
 
-    let result = render_code_frame(&source, &location, &options).unwrap();
+    let result = render_for_snapshot(&source, &location, &options).unwrap();
     assert_snapshot!(result, @r"
       1 | ...
     > 2 | ...aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa...
@@ -183,7 +198,7 @@ fn test_long_line_at_start() {
         ..Default::default()
     };
 
-    let result = render_code_frame(&source, &location, &options).unwrap();
+    let result = render_for_snapshot(&source, &location, &options).unwrap();
     assert_snapshot!(result, @r"
     > 1 | aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa...
         |     ^
@@ -210,7 +225,7 @@ fn test_long_line_at_end() {
         ..Default::default()
     };
 
-    let result = render_code_frame(&source, &location, &options).unwrap();
+    let result = render_for_snapshot(&source, &location, &options).unwrap();
     assert_snapshot!(result, @r"
     > 1 | ...aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
         |                                                 ^
@@ -241,7 +256,7 @@ fn test_long_line_multiline_aligned() {
         ..Default::default()
     };
 
-    let result = render_code_frame(&source, &location, &options).unwrap();
+    let result = render_for_snapshot(&source, &location, &options).unwrap();
     assert_snapshot!(result, @r"
       1 | ...bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb...
     > 2 | ...cccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccc...
@@ -265,7 +280,7 @@ fn test_context_lines() {
         ..Default::default()
     };
 
-    let result = render_code_frame(source, &location, &options).unwrap();
+    let result = render_for_snapshot(source, &location, &options).unwrap();
     assert_snapshot!(result, @r"
       2 | line 2
       3 | line 3
@@ -297,7 +312,7 @@ fn test_gutter_width_alignment() {
         ..Default::default()
     };
 
-    let result = render_code_frame(&source, &location, &options).unwrap();
+    let result = render_for_snapshot(&source, &location, &options).unwrap();
     assert_snapshot!(result, @r"
        97 | line 97
        98 | line 98
@@ -331,7 +346,7 @@ fn test_large_file() {
         ..Default::default()
     };
 
-    let result = render_code_frame(&source, &location, &options).unwrap();
+    let result = render_for_snapshot(&source, &location, &options).unwrap();
     assert_snapshot!(result, @r"
       24998 | line 24998 xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
       24999 | line 24999 xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
@@ -365,7 +380,7 @@ fn test_long_error_span() {
         ..Default::default()
     };
 
-    let result = render_code_frame(&source, &location, &options).unwrap();
+    let result = render_for_snapshot(&source, &location, &options).unwrap();
     assert_snapshot!(result, @r"
     > 1 | ...aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa...
         |    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -399,7 +414,7 @@ Another paragraph.
         ..Default::default()
     };
 
-    let result = render_code_frame(source, &location, &options).unwrap();
+    let result = render_for_snapshot(source, &location, &options).unwrap();
     assert_snapshot!(result, @r"
       1 | # Title
       2 |
@@ -428,7 +443,7 @@ fn test_invalid_column_start_out_of_bounds() {
         ..Default::default()
     };
 
-    let result = render_code_frame(source, &location, &options).unwrap();
+    let result = render_for_snapshot(source, &location, &options).unwrap();
     assert_snapshot!(result, @r"
     > 1 | short
         |      ^
@@ -452,7 +467,7 @@ fn test_invalid_column_end_before_start() {
         ..Default::default()
     };
 
-    let result = render_code_frame(source, &location, &options).unwrap();
+    let result = render_for_snapshot(source, &location, &options).unwrap();
     assert_snapshot!(result, @r"
     > 1 | const x = 123;
         |           ^
@@ -479,7 +494,7 @@ fn test_invalid_column_both_out_of_bounds() {
         ..Default::default()
     };
 
-    let result = render_code_frame(source, &location, &options).unwrap();
+    let result = render_for_snapshot(source, &location, &options).unwrap();
     assert_snapshot!(result, @r"
     > 1 | abc
         |    ^
@@ -503,7 +518,7 @@ fn test_invalid_multiline_end_column_out_of_bounds() {
         ..Default::default()
     };
 
-    let result = render_code_frame(source, &location, &options).unwrap();
+    let result = render_for_snapshot(source, &location, &options).unwrap();
     assert_snapshot!(result, @r"
     > 1 | line1
         |  ^^^
@@ -536,7 +551,7 @@ fn test_column_semantics_explicit_end() {
         ..Default::default()
     };
 
-    let result = render_code_frame(source, &location, &options).unwrap();
+    let result = render_for_snapshot(source, &location, &options).unwrap();
     assert_snapshot!(result, @r"
     > 1 | const x = 123;
         |           ^
@@ -555,7 +570,7 @@ fn test_column_semantics_explicit_end() {
         }), // Exclusive: marks [11, 14) = columns 11, 12, 13
     };
 
-    let result = render_code_frame(source, &location2, &options).unwrap();
+    let result = render_for_snapshot(source, &location2, &options).unwrap();
     assert_snapshot!(result, @r"
     > 1 | const x = 123;
         |           ^^^