diff --git a/cli/tests/common/test_environment.rs b/cli/tests/common/test_environment.rs
index b08aee8cf4..6a7bbffb02 100644
--- a/cli/tests/common/test_environment.rs
+++ b/cli/tests/common/test_environment.rs
@@ -15,6 +15,7 @@
 use std::cell::RefCell;
 use std::collections::HashMap;
 use std::ffi::OsStr;
+use std::ffi::OsString;
 use std::path::Path;
 use std::path::PathBuf;
 
@@ -36,7 +37,7 @@ pub struct TestEnvironment {
     env_root: PathBuf,
     home_dir: PathBuf,
     config_path: PathBuf,
-    env_vars: HashMap<String, String>,
+    env_vars: HashMap<OsString, OsString>,
     config_file_number: RefCell<i64>,
     command_number: RefCell<i64>,
 }
@@ -120,11 +121,11 @@ impl TestEnvironment {
         // We want to keep the "PATH" environment variable to allow accessing
         // executables like `git` from the PATH.
         cmd.env("PATH", std::env::var_os("PATH").unwrap_or_default());
-        cmd.env("HOME", self.home_dir.to_str().unwrap());
+        cmd.env("HOME", &self.home_dir);
         // Prevent git.subprocess from reading outside git config
         cmd.env("GIT_CONFIG_SYSTEM", "/dev/null");
         cmd.env("GIT_CONFIG_GLOBAL", "/dev/null");
-        cmd.env("JJ_CONFIG", self.config_path.to_str().unwrap());
+        cmd.env("JJ_CONFIG", &self.config_path);
         cmd.env("JJ_USER", "Test User");
         cmd.env("JJ_EMAIL", "test.user@example.com");
         cmd.env("JJ_OP_HOSTNAME", "host.example.com");
@@ -202,7 +203,7 @@ impl TestEnvironment {
         .unwrap();
     }
 
-    pub fn add_env_var(&mut self, key: impl Into<String>, val: impl Into<String>) {
+    pub fn add_env_var(&mut self, key: impl Into<OsString>, val: impl Into<OsString>) {
         self.env_vars.insert(key.into(), val.into());
     }
 
@@ -211,7 +212,7 @@ impl TestEnvironment {
     pub fn set_up_fake_bisector(&mut self) -> PathBuf {
         let bisection_script = self.env_root().join("bisection_script");
         std::fs::write(&bisection_script, "").unwrap();
-        self.add_env_var("BISECTION_SCRIPT", bisection_script.to_str().unwrap());
+        self.add_env_var("BISECTION_SCRIPT", &bisection_script);
         bisection_script
     }
 
@@ -230,7 +231,7 @@ impl TestEnvironment {
         "#});
         let edit_script = self.env_root().join("edit_script");
         std::fs::write(&edit_script, "").unwrap();
-        self.add_env_var("EDIT_SCRIPT", edit_script.to_str().unwrap());
+        self.add_env_var("EDIT_SCRIPT", &edit_script);
         edit_script
     }
 
@@ -244,7 +245,7 @@ impl TestEnvironment {
         "#});
         let edit_script = self.env_root().join("diff_edit_script");
         std::fs::write(&edit_script, "").unwrap();
-        self.add_env_var("DIFF_EDIT_SCRIPT", edit_script.to_str().unwrap());
+        self.add_env_var("DIFF_EDIT_SCRIPT", &edit_script);
         edit_script
     }
 
diff --git a/cli/tests/test_git_clone.rs b/cli/tests/test_git_clone.rs
index fce9729134..c85befced2 100644
--- a/cli/tests/test_git_clone.rs
+++ b/cli/tests/test_git_clone.rs
@@ -1107,10 +1107,7 @@ fn test_git_clone_with_global_git_remote_config() {
                 prune = true
         "#},
     );
-    test_env.add_env_var(
-        "GIT_CONFIG_GLOBAL",
-        test_env.env_root().join("git-config").to_str().unwrap(),
-    );
+    test_env.add_env_var("GIT_CONFIG_GLOBAL", test_env.env_root().join("git-config"));
 
     let root_dir = test_env.work_dir("");
     let git_repo_path = root_dir.root().join("source");
diff --git a/cli/tests/test_git_remotes.rs b/cli/tests/test_git_remotes.rs
index e713af69d8..f43d84e8db 100644
--- a/cli/tests/test_git_remotes.rs
+++ b/cli/tests/test_git_remotes.rs
@@ -544,10 +544,7 @@ fn test_git_remote_with_global_git_remote_config() {
                 fetch = +refs/heads/*:refs/remotes/foo/*
         "#},
     );
-    test_env.add_env_var(
-        "GIT_CONFIG_GLOBAL",
-        test_env.env_root().join("git-config").to_str().unwrap(),
-    );
+    test_env.add_env_var("GIT_CONFIG_GLOBAL", test_env.env_root().join("git-config"));
 
     test_env.run_jj_in(".", ["git", "init", "repo"]).success();
     let work_dir = test_env.work_dir("repo");