test: move application tests to tests/

test_support/test_helpers -> tests/support; watched_at unified w/ domain test_watched_at (2024-03-15).
Kept inline: users::diary_filter tests (feed_sort_to_direction_all_variants, paged_user_filter_builds_correctly) - pub(super) helpers in private module.
Dropped stale never-compiled users/tests/get_users.rs (old execute signature).

crates/application/tests/diary/delete_review_test.rs

@@ -0,0 +1,85 @@
+use domain::testing::{test_movie_with_year, test_review};
+use std::sync::Arc;
+
+use domain::{
+    ports::{MovieCommand, MovieQuery, ReviewRepository},
+    testing::{FakeDiaryQuery, InMemoryStore, NoopEventPublisher},
+    value_objects::{MovieId, UserId},
+};
+
+use application::{
+    diary::commands::DeleteReviewCommand, diary::delete_review, diary::deps::DeleteReviewDeps,
+};
+
+#[tokio::test]
+async fn deleting_a_review_removes_it() {
+    let movies = InMemoryStore::new();
+    let reviews = Arc::clone(&movies);
+    let diary = FakeDiaryQuery::new();
+    let events = NoopEventPublisher::new();
+
+    let movie = test_movie_with_year("Terminator", 1984);
+    let user_id = UserId::from_uuid(uuid::Uuid::new_v4());
+    let review = test_review(movie.id(), &user_id, 4);
+
+    movies.upsert_movie(&movie).await.unwrap();
+    reviews.save_review(&review).await.unwrap();
+    diary.seed_history(movie.clone(), vec![]);
+
+    let deps = DeleteReviewDeps {
+        review: Arc::clone(&reviews) as _,
+        diary: diary.clone() as _,
+        movie_command: Arc::clone(&movies) as _,
+        event_publisher: Arc::clone(&events) as _,
+    };
+
+    delete_review::execute(
+        &deps,
+        DeleteReviewCommand {
+            review_id: review.id().value(),
+            requesting_user_id: user_id.value(),
+        },
+    )
+    .await
+    .unwrap();
+
+    assert_eq!(reviews.review_count(), 0, "review should be deleted");
+    assert!(
+        movies.get_movie_by_id(movie.id()).await.unwrap().is_none(),
+        "movie should be deleted when no reviews remain"
+    );
+}
+
+#[tokio::test]
+async fn deleting_another_users_review_is_unauthorized() {
+    let reviews = InMemoryStore::new();
+    let diary = FakeDiaryQuery::new();
+    let movies = Arc::clone(&reviews);
+    let events = NoopEventPublisher::new();
+
+    let movie_id = MovieId::from_uuid(uuid::Uuid::new_v4());
+    let owner_id = UserId::from_uuid(uuid::Uuid::new_v4());
+    let other_id = uuid::Uuid::new_v4();
+    let review = test_review(&movie_id, &owner_id, 4);
+
+    reviews.save_review(&review).await.unwrap();
+
+    let deps = DeleteReviewDeps {
+        review: Arc::clone(&reviews) as _,
+        diary: diary as _,
+        movie_command: movies as _,
+        event_publisher: Arc::clone(&events) as _,
+    };
+
+    let result = delete_review::execute(
+        &deps,
+        DeleteReviewCommand {
+            review_id: review.id().value(),
+            requesting_user_id: other_id,
+        },
+    )
+    .await;
+
+    assert!(result.is_err(), "wrong user should not be able to delete");
+    assert_eq!(reviews.review_count(), 1, "review should still exist");
+}