Replace unsafe set_var in color_always test with LsColors FromStr

Co-authored-by: KSXGitHub <11488886+KSXGitHub@users.noreply.github.com>

Author: Copilot

src/ls_colors.rs

@@ -1,5 +1,7 @@
 use crate::visualizer::coloring::Color;
 use lscolors::{Indicator, LsColors as LsColorsCrate};
+use std::convert::Infallible;
+use std::str::FromStr;
 
 /// ANSI color prefix strings for terminal output, initialized from the `LS_COLORS` environment
 /// variable.
@@ -14,7 +16,10 @@ pub struct LsColors {
 impl LsColors {
     /// Initialize by reading the current environment's `LS_COLORS`.
     pub fn from_env() -> Self {
-        let ls_colors = LsColorsCrate::from_env().unwrap_or_default();
+        Self::from_ls_colors_crate(&LsColorsCrate::from_env().unwrap_or_default())
+    }
+
+    fn from_ls_colors_crate(ls_colors: &LsColorsCrate) -> Self {
         let prefix_for = |indicator: Indicator| {
             ls_colors
                 .style_for_indicator(indicator)
@@ -39,3 +44,15 @@ impl LsColors {
         }
     }
 }
+
+impl FromStr for LsColors {
+    type Err = Infallible;
+    /// Parse an `LS_COLORS`-format string into an [`LsColors`].
+    ///
+    /// This never fails; unrecognized or invalid entries are silently ignored.
+    fn from_str(input: &str) -> Result<Self, Self::Err> {
+        Ok(Self::from_ls_colors_crate(&LsColorsCrate::from_string(
+            input,
+        )))
+    }
+}

tests/usual_cli.rs

@@ -880,9 +880,7 @@ fn color_always() {
     data_tree.par_sort_by(|left, right| left.size().cmp(&right.size()).reverse());
     *data_tree.name_mut() = OsStringDisplay::os_string_from(".");
 
-    // SAFETY: tests that set LS_COLORS all use the same constant value, so there is no data race.
-    unsafe { std::env::set_var("LS_COLORS", LS_COLORS) };
-    let ls_colors = LsColors::from_env();
+    let ls_colors: LsColors = LS_COLORS.parse().expect("parse LS_COLORS");
     let map = HashMap::from([
         (
             OsStringDisplay::os_string_from("file-a1.txt"),