chore: checkpoint before Python removal

vendor/tokio/tests/fs_canonicalize_dir.rs

@@ -0,0 +1,22 @@
+#![warn(rust_2018_idioms)]
+#![cfg(all(feature = "full", not(target_os = "wasi")))] // WASI does not support all fs operations
+
+use tokio::fs;
+
+#[tokio::test]
+#[cfg(unix)]
+async fn canonicalize_root_dir_unix() {
+    assert_eq!(fs::canonicalize("/.").await.unwrap().to_str().unwrap(), "/");
+}
+
+#[tokio::test]
+#[cfg(windows)]
+async fn canonicalize_root_dir_windows() {
+    // 2-step let bindings due to Rust memory semantics
+    let dir_path = fs::canonicalize("C:\\.\\").await.unwrap();
+
+    let dir_name = dir_path.to_str().unwrap();
+
+    assert!(dir_name.starts_with("\\\\"));
+    assert!(dir_name.ends_with("C:\\"));
+}