chore: checkpoint before Python removal

vendor/futures/tests/test_macro.rs

@@ -0,0 +1,20 @@
+#[futures_test::test]
+async fn it_works() {
+    let fut = async { true };
+    assert!(fut.await);
+
+    let fut = async { false };
+    assert!(!fut.await);
+}
+
+#[should_panic]
+#[futures_test::test]
+async fn it_is_being_run() {
+    let fut = async { false };
+    assert!(fut.await);
+}
+
+#[futures_test::test]
+async fn return_ty() -> Result<(), ()> {
+    Ok(())
+}