Save color configuration in a thread local variable

Author: bjacotg

googletest/Cargo.toml

@@ -41,4 +41,3 @@ rustversion = "1.0.14"
 [dev-dependencies]
 indoc = "2"
 quickcheck = "1.0.3"
-serial_test = "2.0.0"

googletest/src/matcher_support/summarize_diff.rs

@@ -17,7 +17,7 @@
 use crate::matcher_support::edit_distance;
 #[rustversion::since(1.70)]
 use std::io::IsTerminal;
-use std::{borrow::Cow, fmt::Display};
+use std::{borrow::Cow, cell::Cell, fmt::Display};
 
 /// Returns a string describing how the expected and actual lines differ.
 ///
@@ -81,9 +81,9 @@ pub(crate) fn create_diff_reversed(
 }
 
 // Produces the header, with or without coloring depending on
-// stdout_supports_color()
+// USE_COLOR
 fn summary_header() -> Cow<'static, str> {
-    if stdout_supports_color() {
+    if USE_COLOR.with(Cell::get) {
         format!(
             "Difference(-{ACTUAL_ONLY_STYLE}actual{RESET_ALL} / +{EXPECTED_ONLY_STYLE}expected{RESET_ALL}):"
         ).into()
@@ -294,6 +294,10 @@ impl<'a> Default for Buffer<'a> {
     }
 }
 
+thread_local! {
+  pub(crate) static USE_COLOR: Cell<bool> = Cell::new(stdout_supports_color());
+}
+
 #[rustversion::since(1.70)]
 fn stdout_supports_color() -> bool {
     #[allow(clippy::incompatible_msrv)]
@@ -389,14 +393,14 @@ impl SummaryBuilder {
     }
 
     fn reset_ansi(&mut self) {
-        if !self.last_ansi_style.is_empty() && stdout_supports_color() {
+        if !self.last_ansi_style.is_empty() && USE_COLOR.with(Cell::get) {
             self.summary.push_str(RESET_ALL);
             self.last_ansi_style = "";
         }
     }
 
     fn set_ansi(&mut self, ansi_style: &'static str) {
-        if !stdout_supports_color() || self.last_ansi_style == ansi_style {
+        if !USE_COLOR.with(Cell::get) || self.last_ansi_style == ansi_style {
             return;
         }
         if !self.last_ansi_style.is_empty() {
@@ -412,7 +416,6 @@ mod tests {
     use super::*;
     use crate::{matcher_support::edit_distance::Mode, prelude::*};
     use indoc::indoc;
-    use serial_test::{parallel, serial};
     use std::fmt::Write;
 
     // Make a long text with each element of the iterator on one line.
@@ -428,13 +431,11 @@ mod tests {
     }
 
     #[test]
-    #[parallel]
     fn create_diff_smaller_than_one_line() -> Result<()> {
         verify_that!(create_diff("One", "Two", Mode::Exact), eq(""))
     }
 
     #[test]
-    #[parallel]
     fn create_diff_exact_same() -> Result<()> {
         let expected = indoc! {"
             One
@@ -451,7 +452,6 @@ mod tests {
     }
 
     #[test]
-    #[parallel]
     fn create_diff_multiline_diff() -> Result<()> {
         let expected = indoc! {"
             prefix
@@ -484,13 +484,11 @@ mod tests {
     }
 
     #[test]
-    #[parallel]
     fn create_diff_exact_unrelated() -> Result<()> {
         verify_that!(create_diff(&build_text(1..500), &build_text(501..1000), Mode::Exact), eq(""))
     }
 
     #[test]
-    #[parallel]
     fn create_diff_exact_small_difference() -> Result<()> {
         verify_that!(
             create_diff(&build_text(1..50), &build_text(1..51), Mode::Exact),
@@ -508,27 +506,9 @@ mod tests {
         )
     }
 
-    // Test with color enabled.
-
-    struct ForceColor;
-
-    fn force_color() -> ForceColor {
-        std::env::set_var("FORCE_COLOR", "1");
-        std::env::remove_var("NO_COLOR");
-        ForceColor
-    }
-
-    impl Drop for ForceColor {
-        fn drop(&mut self) {
-            std::env::remove_var("FORCE_COLOR");
-            std::env::set_var("NO_COLOR", "1");
-        }
-    }
-
     #[test]
-    #[serial]
     fn create_diff_exact_small_difference_with_color() -> Result<()> {
-        let _keep = force_color();
+        USE_COLOR.with(|cell| cell.set(true));
 
         verify_that!(
             create_diff(&build_text(1..50), &build_text(1..51), Mode::Exact),
@@ -547,9 +527,9 @@ mod tests {
     }
 
     #[test]
-    #[serial]
     fn create_diff_exact_difference_with_inline_color() -> Result<()> {
-        let _keep = force_color();
+        USE_COLOR.with(|cell| cell.set(true));
+
         let actual = indoc!(
             "There is a home in Nouvelle Orleans
             They say, it is the rising sons

googletest/src/matchers/display_matcher.rs

@@ -68,7 +68,6 @@ impl<T: Debug + Display + Copy, InnerMatcher: for<'a> Matcher<&'a str>> Matcher<
 mod tests {
     use crate::prelude::*;
     use indoc::indoc;
-    use serial_test::parallel;
     use std::fmt::{Debug, Display, Error, Formatter};
 
     #[test]
@@ -103,7 +102,6 @@ mod tests {
     }
 
     #[test]
-    #[parallel]
     fn display_displays_error_message_with_explanation_from_inner_matcher() -> Result<()> {
         let result = verify_that!("123\n234", displays_as(eq("123\n345")));
 

googletest/src/matchers/eq_matcher.rs

@@ -135,7 +135,6 @@ fn to_display_output(string: &str) -> Option<String> {
 mod tests {
     use crate::prelude::*;
     use indoc::indoc;
-    use serial_test::parallel;
 
     #[test]
     fn eq_matches_string_reference_with_string_reference() -> Result<()> {
@@ -160,7 +159,6 @@ mod tests {
     }
 
     #[test]
-    #[parallel]
     fn eq_struct_debug_diff() -> Result<()> {
         #[derive(Debug, PartialEq)]
         struct Strukt {
@@ -190,7 +188,6 @@ mod tests {
     }
 
     #[test]
-    #[parallel]
     fn eq_vec_debug_diff() -> Result<()> {
         let result = verify_that!(vec![1, 2, 3], eq(&vec![1, 3, 4]));
         verify_that!(
@@ -213,7 +210,6 @@ mod tests {
     }
 
     #[test]
-    #[parallel]
     fn eq_vec_debug_diff_length_mismatch() -> Result<()> {
         let result = verify_that!(vec![1, 2, 3, 4, 5], eq(&vec![1, 3, 5]));
         verify_that!(
@@ -237,7 +233,6 @@ mod tests {
     }
 
     #[test]
-    #[parallel]
     fn eq_debug_diff_common_lines_omitted() -> Result<()> {
         let result = verify_that!((1..50).collect::<Vec<_>>(), eq(&(3..52).collect::<Vec<_>>()));
         verify_that!(
@@ -262,7 +257,6 @@ mod tests {
     }
 
     #[test]
-    #[parallel]
     fn eq_debug_diff_5_common_lines_not_omitted() -> Result<()> {
         let result = verify_that!((1..8).collect::<Vec<_>>(), eq(&(3..10).collect::<Vec<_>>()));
         verify_that!(
@@ -287,7 +281,6 @@ mod tests {
     }
 
     #[test]
-    #[parallel]
     fn eq_debug_diff_start_common_lines_omitted() -> Result<()> {
         let result = verify_that!((1..50).collect::<Vec<_>>(), eq(&(1..52).collect::<Vec<_>>()));
         verify_that!(
@@ -309,7 +302,6 @@ mod tests {
     }
 
     #[test]
-    #[parallel]
     fn eq_debug_diff_end_common_lines_omitted() -> Result<()> {
         let result = verify_that!((1..52).collect::<Vec<_>>(), eq(&(3..52).collect::<Vec<_>>()));
         verify_that!(
@@ -348,7 +340,6 @@ mod tests {
     }
 
     #[test]
-    #[parallel]
     fn match_explanation_contains_diff_of_strings_if_more_than_one_line() -> Result<()> {
         let result = verify_that!(
             indoc!(

googletest/src/matchers/str_matcher.rs

@@ -574,7 +574,6 @@ mod tests {
     use crate::matcher::MatcherResult;
     use crate::prelude::*;
     use indoc::indoc;
-    use serial_test::parallel;
 
     #[test]
     fn matches_string_reference_with_equal_string_reference() -> Result<()> {
@@ -953,7 +952,6 @@ mod tests {
     }
 
     #[test]
-    #[parallel]
     fn match_explanation_for_starts_with_ignores_trailing_lines_in_actual_string() -> Result<()> {
         let result = verify_that!(
             indoc!(