Fix awaits only, making cache.invalidate return a future can be separate
diff --git a/test/async_cache_test.dart b/test/async_cache_test.dart
index 0a5e0f0..a4f452f 100644
--- a/test/async_cache_test.dart
+++ b/test/async_cache_test.dart
@@ -58,9 +58,9 @@
     var timesCalled = 0;
     call() async => 'Called ${++timesCalled}';
     expect(await cache.fetch(call), 'Called 1');
-    await cache.invalidate();
+    cache.invalidate();
     expect(await cache.fetch(call), 'Called 2');
-    await cache.invalidate();
+    cache.invalidate();
     expect(await cache.fetch(call), 'Called 3');
   });
 
@@ -129,9 +129,9 @@
     }
 
     expect(await cache.fetchStream(call).toList(), ['Called 1']);
-    await cache.invalidate();
+    cache.invalidate();
     expect(await cache.fetchStream(call).toList(), ['Called 2']);
-    await cache.invalidate();
+    cache.invalidate();
     expect(await cache.fetchStream(call).toList(), ['Called 3']);
   });