diff --git a/ruff_cli/src/commands.rs b/ruff_cli/src/commands.rs
index 65e605735d..57eb447998 100644
--- a/ruff_cli/src/commands.rs
+++ b/ruff_cli/src/commands.rs
@@ -120,7 +120,7 @@ pub fn run(
                             location: Location::default(),
                             end_location: Location::default(),
                             fix: None,
-                            filename: path.to_string_lossy().to_string(),
+                            filename: format!("{}", path.display()),
                             source: None,
                         }])
                     } else {
diff --git a/ruff_cli/tests/integration_test.rs b/ruff_cli/tests/integration_test.rs
index d2f77172c6..e82b774d84 100644
--- a/ruff_cli/tests/integration_test.rs
+++ b/ruff_cli/tests/integration_test.rs
@@ -1,9 +1,12 @@
 #![cfg(not(target_family = "wasm"))]
 
+#[cfg(unix)]
+use std::path::Path;
 use std::str;
 
 use anyhow::Result;
 use assert_cmd::Command;
+#[cfg(unix)]
 use path_absolutize::path_dedot;
 
 const BIN_NAME: &str = "ruff";
@@ -50,6 +53,7 @@ fn test_stdin_filename() -> Result<()> {
     Ok(())
 }
 
+#[cfg(unix)]
 #[test]
 fn test_stdin_json() -> Result<()> {
     let mut cmd = Command::cargo_bin(BIN_NAME)?;
@@ -58,6 +62,11 @@ fn test_stdin_json() -> Result<()> {
         .write_stdin("import os\n")
         .assert()
         .failure();
+
+    let directory = path_dedot::CWD.to_str().unwrap();
+    let binding = Path::new(directory).join("F401.py");
+    let file_path = binding.display();
+
     assert_eq!(
         str::from_utf8(&output.get_output().stdout)?,
         format!(
@@ -85,11 +94,10 @@ fn test_stdin_json() -> Result<()> {
       "row": 1,
       "column": 10
     }},
-    "filename": "{}/F401.py"
+    "filename": "{file_path}"
   }}
 ]
-"#,
-            path_dedot::CWD.to_str().unwrap()
+"#
         )
     );
     Ok(())
diff --git a/src/fs.rs b/src/fs.rs
index a50ba8e10a..2e5b347af6 100644
--- a/src/fs.rs
+++ b/src/fs.rs
@@ -1,4 +1,3 @@
-use std::borrow::Cow;
 use std::fs::File;
 use std::io::{BufReader, Read};
 use std::path::{Path, PathBuf};
@@ -62,11 +61,11 @@ pub fn normalize_path_to<P: AsRef<Path>, R: AsRef<Path>>(path: P, project_root:
 }
 
 /// Convert an absolute path to be relative to the current working directory.
-pub fn relativize_path(path: &Path) -> Cow<str> {
+pub fn relativize_path(path: &Path) -> String {
     if let Ok(path) = path.strip_prefix(&*path_dedot::CWD) {
-        return path.to_string_lossy();
+        return format!("{}", path.display());
     }
-    path.to_string_lossy()
+    format!("{}", path.display())
 }
 
 /// Read a file's contents from disk.
diff --git a/src/rules/flake8_executable/mod.rs b/src/rules/flake8_executable/mod.rs
index 6fcc956c93..f27d82ea9b 100644
--- a/src/rules/flake8_executable/mod.rs
+++ b/src/rules/flake8_executable/mod.rs
@@ -2,6 +2,7 @@
 pub(crate) mod helpers;
 pub(crate) mod rules;
 
+#[cfg(unix)]
 #[cfg(test)]
 mod tests {
     use std::path::Path;
diff --git a/src/rules/flake8_no_pep420/mod.rs b/src/rules/flake8_no_pep420/mod.rs
index 88d8422d11..04d38aeff3 100644
--- a/src/rules/flake8_no_pep420/mod.rs
+++ b/src/rules/flake8_no_pep420/mod.rs
@@ -21,11 +21,13 @@ mod tests {
     #[test_case(Path::new("test_pass_namespace_package"); "INP001_5")]
     fn test_flake8_no_pep420(path: &Path) -> Result<()> {
         let snapshot = format!("{}", path.to_string_lossy());
+        // Platform-independent paths
+        let p = PathBuf::from(format!(
+            "./resources/test/fixtures/flake8_no_pep420/{}/example.py",
+            path.display()
+        ));
         let diagnostics = test_path(
-            Path::new("./resources/test/fixtures/flake8_no_pep420")
-                .join(path)
-                .join("example.py")
-                .as_path(),
+            p.as_path(),
             &Settings {
                 namespace_packages: vec![PathBuf::from(
                     "./resources/test/fixtures/flake8_no_pep420/test_pass_namespace_package",
diff --git a/src/rules/flake8_no_pep420/rules.rs b/src/rules/flake8_no_pep420/rules.rs
index 932fabe8f8..fdf6d29546 100644
--- a/src/rules/flake8_no_pep420/rules.rs
+++ b/src/rules/flake8_no_pep420/rules.rs
@@ -8,7 +8,7 @@ use crate::{fs, violations};
 pub fn implicit_namespace_package(path: &Path, package: Option<&Path>) -> Option<Diagnostic> {
     if package.is_none() {
         Some(Diagnostic::new(
-            violations::ImplicitNamespacePackage(fs::relativize_path(path).to_string()),
+            violations::ImplicitNamespacePackage(fs::relativize_path(path)),
             Range::default(),
         ))
     } else {