--- a/testing/mozbase/rust/mozrunner/src/lib.rs
+++ b/testing/mozbase/rust/mozrunner/src/lib.rs
@@ -1,11 +1,13 @@
 #[macro_use]
 extern crate log;
 extern crate mozprofile;
 #[cfg(target_os = "windows")]
 extern crate winreg;
+#[cfg(target_os = "macos")]
+extern crate dirs;
 
 pub mod firefox_args;
 pub mod path;
 pub mod runner;
 
 pub use runner::platform::firefox_default_path;

--- a/testing/mozbase/rust/mozrunner/src/runner.rs
+++ b/testing/mozbase/rust/mozrunner/src/runner.rs
@@ -306,28 +306,28 @@ pub mod platform {
     pub fn arg_prefix_char(c: char) -> bool {
         c == '-'
     }
 }
 
 #[cfg(target_os = "macos")]
 pub mod platform {
     use path::{find_binary, is_binary};
-    use std::env;
     use std::path::PathBuf;
+    use dirs;
 
     /// Searches the system path for `firefox-bin`, then looks for
     /// `Applications/Firefox.app/Contents/MacOS/firefox-bin` under both `/`
     /// (system root) and the user home directory.
     pub fn firefox_default_path() -> Option<PathBuf> {
         if let Some(path) = find_binary("firefox-bin") {
             return Some(path);
         }
 
-        let home = env::home_dir();
+        let home = dirs::home_dir();
         for &(prefix_home, trial_path) in [
             (
                 false,
                 "/Applications/Firefox.app/Contents/MacOS/firefox-bin",
             ),
             (true, "Applications/Firefox.app/Contents/MacOS/firefox-bin"),
         ].iter()
         {