code refactor

Reviewed-on: #26

crates/application/tests/integrations/cleanup_test.rs

@@ -0,0 +1,12 @@
+use domain::testing::InMemoryStore;
+
+use application::integrations::cleanup;
+
+#[tokio::test]
+async fn returns_zero_when_nothing_to_clean() {
+    let watch_events = InMemoryStore::new();
+
+    let count = cleanup::execute(watch_events).await.unwrap();
+
+    assert_eq!(count, 0);
+}