fix: make theme test more lenient

The test now only considers our part of the backtrace, allowing for
changes in rust std library to not break the test

color-eyre/tests/theme.rs

@@ -150,9 +150,9 @@ fn test_backwards_compatibility(target: String, file_name: &str) {
     // `unwrap` should never fail with files generated by this function
     let control = String::from_utf8(fs::read(file_path).unwrap()).unwrap();
 
-    fn f(s: &str) -> (Vec<Output>, Vec<AnsiSequence>) {
-        let all: Vec<_> = s.ansi_parse().collect();
-        let ansi: Vec<_> = s
+    fn split_ansi_output(input: &str) -> (Vec<Output>, Vec<AnsiSequence>) {
+        let all: Vec<_> = input.ansi_parse().collect();
+        let ansi: Vec<_> = input
             .ansi_parse()
             .filter_map(|x| {
                 if let Output::Escape(ansi) = x {
@@ -165,8 +165,26 @@ fn test_backwards_compatibility(target: String, file_name: &str) {
         (all, ansi)
     }
 
-    let (_control_tokens, control_ansi) = f(&control);
-    let (_target_tokens, target_ansi) = f(&target);
+    fn normalize_backtrace(input: &str) -> String {
+        input
+            .lines()
+            .take_while(|v| !v.contains("core::panic"))
+            .collect::<Vec<_>>()
+            .join("\n")
+    }
+
+    let control = normalize_backtrace(&control);
+    let target = normalize_backtrace(&target);
+    let (_control_tokens, control_ansi) = split_ansi_output(&control);
+    let (_target_tokens, target_ansi) = split_ansi_output(&target);
+
+    fn section(title: &str, content: impl AsRef<str>) -> String {
+        format!(
+            "{}\n{}",
+            format!("-------- {title} --------").red(),
+            content.as_ref()
+        )
+    }
 
     // pretty_assertions::assert_eq!(target, control);
     let msg = [
@@ -175,23 +193,21 @@ fn test_backwards_compatibility(target: String, file_name: &str) {
         format!("{}", "\x1b[0m\n\nANSI escape sequences are not identical to control!".red()),
         // ^ `\x1b[0m` clears previous ANSI escape sequences
 
-        format!("{}", "CONTROL:".red()),
-        format!("{}{}", "CONTROL STRING =\n".red(), &control),
-        //format!("{}{:?}", "CONTROL DEBUG STRING =\n".red(), &control),
-        //format!("{}{:?}", "CONTROL ANSI PARSER OUTPUT =\n".red(), &_control_tokens),
-        //format!("{}{:?}", "CONTROL ANSI PARSER ANSI =\n".red(), &control_ansi),
+        section("CONTROL STRING", &control),
+        // section("CONTROL DEBUG STRING", format!("{control:?}")),
+        // section("CONTROL ANSI PARSER OUTPUT", format!("{_control_tokens:?}")),
+        // section("CONTROL ANSI PARSER ANSI", format!("{control_ansi:?}")),
 
-        format!("{}", "CURRENT:".red()),
-        format!("{}{}", "CURRENT STRING =\n".red(), &target),
-        //format!("{}{:?}", "CURRENT DEBUG STRING =\n".red(), &target),
-        //format!("{}{:?}", "CURRENT ANSI PARSER OUTPUT =\n".red(), &_target_tokens),
-        //format!("{}{:?}", "CURRENT ANSI PARSER ANSI =\n".red(), &target_ansi),
+        section("CURRENT STRING", &target),
+        // section("CURRENT DEBUG STRING", format!("{target:?}")),
+        // section("CURRENT ANSI PARSER OUTPUT", format!("{_target_tokens:?}")),
+        // section("CURRENT ANSI PARSER ANSI", format!("{target_ansi:?}")),
 
         format!("{}", "See the src of this test for more information about the test and ways to include/exclude debugging information.\n\n".red()),
 
     ].join("\n\n");
 
-    assert_eq!(target_ansi, control_ansi, "{}", &msg);
+    pretty_assertions::assert_eq!(target_ansi, control_ansi, "{}", &msg);
 
     /*
         # Tips for debugging test failures