1 files changed, 41 insertions, 0 deletions
diff --git a/third_party/rust/fluent-testing/src/fs.rs b/third_party/rust/fluent-testing/src/fs.rs
new file mode 100644
index 0000000000..1efd6a90cb
--- /dev/null
+++ b/third_party/rust/fluent-testing/src/fs.rs
@@ -0,0 +1,41 @@
+use std::cell::RefCell;
+use std::collections::HashMap;
+use std::path::PathBuf;
+
+#[derive(Default)]
+pub struct MockFileSystem {
+    files: RefCell<HashMap<String, std::io::Result<String>>>,
+}
+
+impl MockFileSystem {
+    pub fn clear(&self) {
+        self.files.borrow_mut().clear();
+    }
+
+    fn get_test_file_path() -> PathBuf {
+        PathBuf::from(std::env!("CARGO_MANIFEST_DIR")).join("resources")
+    }
+
+    fn get_file(&self, path: &str) -> std::io::Result<String> {
+        let mut tmp = self.files.borrow_mut();
+        let result = tmp.entry(path.to_string()).or_insert_with(|| {
+            let root_path = Self::get_test_file_path();
+            let full_path = root_path.join(path);
+            std::fs::read_to_string(full_path)
+        });
+        match result {
+            Ok(s) => Ok(s.to_string()),
+            Err(e) => Err(std::io::Error::new(e.kind(), "Error")),
+        }
+    }
+
+    #[cfg(feature = "sync")]
+    pub fn get_test_file_sync(&self, path: &str) -> std::io::Result<String> {
+        self.get_file(path)
+    }
+
+    #[cfg(feature = "async")]
+    pub async fn get_test_file_async(&self, path: &str) -> std::io::Result<String> {
+        self.get_file(path)
+    }
+}