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/movies/sync_poster_test.rs

@@ -0,0 +1,102 @@
+use crate::support::sync_poster_command;
+use domain::testing::{test_movie_with_external_id, test_movie_with_year};
+use std::sync::Arc;
+
+use uuid::Uuid;
+
+use domain::{
+    errors::DomainError,
+    models::Movie,
+    ports::{MetadataClient, MovieCommand, MovieQuery},
+    testing::{FakeSearchCommand, InMemoryStore, NoopEventPublisher, NoopObjectStorage},
+    value_objects::{ExternalMetadataId, PosterUrl},
+};
+
+use application::movies::{deps::SyncPosterDeps, sync_poster};
+
+fn default_deps() -> SyncPosterDeps {
+    SyncPosterDeps {
+        movie_command: InMemoryStore::new(),
+        movie_query: InMemoryStore::new(),
+        movie_profile: InMemoryStore::new(),
+        metadata: Arc::new(domain::testing::FakeMetadataClient),
+        poster_fetcher: Arc::new(domain::testing::FakePosterFetcher),
+        object_storage: Arc::new(NoopObjectStorage),
+        event_publisher: NoopEventPublisher::new(),
+        search_command: Arc::new(FakeSearchCommand),
+    }
+}
+
+#[tokio::test]
+async fn fails_when_movie_not_found() {
+    let deps = default_deps();
+
+    let result = sync_poster::execute(&deps, sync_poster_command(Uuid::new_v4())).await;
+
+    assert!(result.is_err());
+}
+
+#[tokio::test]
+async fn fails_when_no_external_id() {
+    let movies = InMemoryStore::new();
+    let movie = test_movie_with_year("Test", 2024);
+    let movie_id = movie.id().value();
+    movies.upsert_movie(&movie).await.unwrap();
+
+    let deps = SyncPosterDeps {
+        movie_command: Arc::clone(&movies) as _,
+        movie_query: Arc::clone(&movies) as _,
+        ..default_deps()
+    };
+
+    let result = sync_poster::execute(&deps, sync_poster_command(movie_id)).await;
+
+    assert!(result.is_err());
+}
+
+struct FakeMetaWithPoster;
+
+#[async_trait::async_trait]
+impl MetadataClient for FakeMetaWithPoster {
+    async fn fetch_movie_metadata(
+        &self,
+        _: &domain::models::MetadataSearchCriteria,
+    ) -> Result<Movie, DomainError> {
+        unimplemented!()
+    }
+    async fn get_poster_url(
+        &self,
+        _: &ExternalMetadataId,
+    ) -> Result<Option<PosterUrl>, DomainError> {
+        Ok(Some(
+            PosterUrl::new("https://example.com/poster.jpg".into()).unwrap(),
+        ))
+    }
+}
+
+#[tokio::test]
+async fn syncs_poster_for_movie_with_external_id() {
+    let movies = InMemoryStore::new();
+    let ext_id = ExternalMetadataId::new("tmdb:999".into()).unwrap();
+    let movie = test_movie_with_external_id("Poster Movie", 2024, ext_id);
+    let movie_id = movie.id().value();
+    movies.upsert_movie(&movie).await.unwrap();
+
+    let deps = SyncPosterDeps {
+        movie_command: Arc::clone(&movies) as _,
+        movie_query: Arc::clone(&movies) as _,
+        metadata: Arc::new(FakeMetaWithPoster) as _,
+        ..default_deps()
+    };
+
+    sync_poster::execute(&deps, sync_poster_command(movie_id))
+        .await
+        .unwrap();
+
+    let updated = movies
+        .get_movie_by_id(&domain::value_objects::MovieId::from_uuid(movie_id))
+        .await
+        .unwrap()
+        .unwrap();
+    assert!(updated.poster_path().is_some());
+}