add 400+ unit tests for domain and application layers

Extract ReviewLogger trait to decouple import/integrations
from diary::log_review (cross-module coupling smell).

Add in-memory fakes for all repository ports, enabling
isolated testing of every use case module without a database.

Coverage: domain+application 22% → 80%, 427 tests.

crates/application/src/diary/tests/get_activity_feed.rs

@@ -0,0 +1,139 @@
+use std::sync::Arc;
+
+use async_trait::async_trait;
+use domain::errors::DomainError;
+
+use crate::{
+    diary::get_activity_feed, diary::queries::GetActivityFeedQuery,
+    test_helpers::TestContextBuilder,
+};
+
+#[tokio::test]
+async fn returns_empty_feed() {
+    let ctx = TestContextBuilder::new().build();
+
+    let result = get_activity_feed::execute(
+        &ctx,
+        GetActivityFeedQuery {
+            limit: 10,
+            offset: 0,
+            sort_by: domain::ports::FeedSortBy::Date,
+            search: None,
+            viewer_user_id: None,
+            filter_following: false,
+        },
+    )
+    .await
+    .unwrap();
+
+    assert!(result.items.is_empty());
+    assert_eq!(result.total_count, 0);
+}
+
+#[tokio::test]
+async fn returns_feed_with_following_filter() {
+    let ctx = TestContextBuilder::new().build();
+
+    let viewer = uuid::Uuid::new_v4();
+
+    let result = get_activity_feed::execute(
+        &ctx,
+        GetActivityFeedQuery {
+            limit: 10,
+            offset: 0,
+            sort_by: domain::ports::FeedSortBy::Date,
+            search: None,
+            viewer_user_id: Some(viewer),
+            filter_following: true,
+        },
+    )
+    .await
+    .unwrap();
+
+    // NoopSocialQueryPort returns empty following, so FollowingFilter
+    // contains only the viewer's id. Feed is empty but the code path is hit.
+    assert!(result.items.is_empty());
+}
+
+struct FakeSocialWithFollowing(Vec<String>);
+
+#[async_trait]
+impl domain::ports::SocialQueryPort for FakeSocialWithFollowing {
+    async fn get_accepted_following_urls(&self, _: uuid::Uuid) -> Result<Vec<String>, DomainError> {
+        Ok(self.0.clone())
+    }
+    async fn count_following(&self, _: uuid::Uuid) -> Result<usize, DomainError> {
+        Ok(0)
+    }
+    async fn count_accepted_followers(&self, _: uuid::Uuid) -> Result<usize, DomainError> {
+        Ok(0)
+    }
+    async fn get_pending_followers(
+        &self,
+        _: uuid::Uuid,
+    ) -> Result<Vec<domain::ports::PendingFollowerInfo>, DomainError> {
+        Ok(vec![])
+    }
+    async fn list_all_followed_remote_actors(
+        &self,
+    ) -> Result<Vec<domain::ports::RemoteActorInfo>, DomainError> {
+        Ok(vec![])
+    }
+}
+
+#[tokio::test]
+async fn following_filter_parses_local_and_remote_urls() {
+    let viewer = uuid::Uuid::new_v4();
+    let local_friend = uuid::Uuid::new_v4();
+
+    let following_urls = vec![
+        format!("http://localhost:3000/users/{}", local_friend),
+        "https://remote.example/actor/1".to_string(),
+    ];
+
+    let social = Arc::new(FakeSocialWithFollowing(following_urls));
+
+    let ctx = TestContextBuilder::new()
+        .with_social_query(social as _)
+        .build();
+
+    let result = get_activity_feed::execute(
+        &ctx,
+        GetActivityFeedQuery {
+            limit: 10,
+            offset: 0,
+            sort_by: domain::ports::FeedSortBy::Date,
+            search: None,
+            viewer_user_id: Some(viewer),
+            filter_following: true,
+        },
+    )
+    .await
+    .unwrap();
+
+    // Feed is empty (no data seeded), but the build_following_filter code path
+    // with actual URL parsing ran without errors.
+    assert!(result.items.is_empty());
+}
+
+#[tokio::test]
+async fn following_filter_without_viewer_returns_none() {
+    let ctx = TestContextBuilder::new().build();
+
+    let result = get_activity_feed::execute(
+        &ctx,
+        GetActivityFeedQuery {
+            limit: 10,
+            offset: 0,
+            sort_by: domain::ports::FeedSortBy::Date,
+            search: None,
+            viewer_user_id: None,
+            filter_following: true,
+        },
+    )
+    .await
+    .unwrap();
+
+    // filter_following=true but viewer_user_id=None → build_following_filter returns None
+    assert!(result.items.is_empty());
+}

crates/application/src/diary/tests/get_diary.rs

@@ -0,0 +1,22 @@
+use crate::{diary::get_diary, diary::queries::GetDiaryQuery, test_helpers::TestContextBuilder};
+
+#[tokio::test]
+async fn returns_empty_page() {
+    let ctx = TestContextBuilder::new().build();
+
+    let result = get_diary::execute(
+        &ctx,
+        GetDiaryQuery {
+            limit: None,
+            offset: None,
+            sort_by: None,
+            movie_id: None,
+            user_id: None,
+        },
+    )
+    .await
+    .unwrap();
+
+    assert!(result.items.is_empty());
+    assert_eq!(result.total_count, 0);
+}

crates/application/src/diary/tests/get_movie_social_page.rs

@@ -0,0 +1,65 @@
+use std::sync::Arc;
+
+use uuid::Uuid;
+
+use domain::{
+    models::Movie,
+    ports::MovieRepository,
+    testing::InMemoryMovieRepository,
+    value_objects::{MovieTitle, ReleaseYear},
+};
+
+use crate::{
+    diary::get_movie_social_page, diary::queries::GetMovieSocialPageQuery,
+    test_helpers::TestContextBuilder,
+};
+
+#[tokio::test]
+async fn fails_when_movie_not_found() {
+    let ctx = TestContextBuilder::new().build();
+
+    let result = get_movie_social_page::execute(
+        &ctx,
+        GetMovieSocialPageQuery {
+            movie_id: Uuid::new_v4(),
+            limit: 10,
+            offset: 0,
+        },
+    )
+    .await;
+
+    assert!(result.is_err());
+}
+
+#[tokio::test]
+async fn returns_movie_social_page() {
+    let movies = InMemoryMovieRepository::new();
+
+    let movie = Movie::new(
+        None,
+        MovieTitle::new("Social Movie".into()).unwrap(),
+        ReleaseYear::new(2024).unwrap(),
+        None,
+        None,
+    );
+    let movie_uuid = movie.id().value();
+    movies.upsert_movie(&movie).await.unwrap();
+
+    let ctx = TestContextBuilder::new()
+        .with_movies(Arc::clone(&movies) as _)
+        .build();
+
+    let result = get_movie_social_page::execute(
+        &ctx,
+        GetMovieSocialPageQuery {
+            movie_id: movie_uuid,
+            limit: 10,
+            offset: 0,
+        },
+    )
+    .await
+    .unwrap();
+
+    assert_eq!(result.movie.title().value(), "Social Movie");
+    assert_eq!(result.reviews.items.len(), 0);
+}

crates/application/src/diary/tests/get_review_history.rs

@@ -0,0 +1,34 @@
+use domain::{
+    models::Movie,
+    services::review_history::Trend,
+    value_objects::{MovieTitle, ReleaseYear},
+};
+
+use crate::{
+    diary::get_review_history, diary::queries::GetReviewHistoryQuery,
+    test_helpers::TestContextBuilder,
+};
+
+#[tokio::test]
+async fn returns_empty_history() {
+    let movie = Movie::new(
+        None,
+        MovieTitle::new("Test".into()).unwrap(),
+        ReleaseYear::new(2024).unwrap(),
+        None,
+        None,
+    );
+    let movie_id = movie.id().value();
+
+    let diary = domain::testing::FakeDiaryRepository::new();
+    diary.seed_history(movie, vec![]);
+
+    let ctx = TestContextBuilder::new().with_diary(diary as _).build();
+
+    let (history, trend) = get_review_history::execute(&ctx, GetReviewHistoryQuery { movie_id })
+        .await
+        .unwrap();
+
+    assert!(history.viewings().is_empty());
+    assert_eq!(trend, Trend::Neutral);
+}

crates/application/src/diary/tests/log_review.rs

@@ -13,9 +13,30 @@ use domain::testing::{InMemoryMovieRepository, InMemoryReviewRepository, NoopEve
 use crate::{
     diary::commands::{LogReviewCommand, MovieInput},
     diary::log_review,
+    diary::review_logger::DefaultReviewLogger,
     test_helpers::TestContextBuilder,
 };
 
+fn build_ctx_with_real_logger(
+    movies: &Arc<InMemoryMovieRepository>,
+    reviews: &Arc<InMemoryReviewRepository>,
+    events: &Arc<NoopEventPublisher>,
+) -> crate::context::AppContext {
+    let logger = Arc::new(DefaultReviewLogger::new(
+        Arc::clone(movies) as _,
+        Arc::clone(reviews) as _,
+        crate::test_helpers::TestContextBuilder::new().watchlist_repo,
+        Arc::new(domain::testing::FakeMetadataClient) as _,
+        Arc::clone(events) as _,
+    ));
+    TestContextBuilder::new()
+        .with_movies(Arc::clone(movies) as _)
+        .with_reviews(Arc::clone(reviews) as _)
+        .with_event_publisher(Arc::clone(events) as _)
+        .with_review_logger(logger)
+        .build()
+}
+
 fn movie_input_manual(title: &str, year: u16) -> MovieInput {
     MovieInput {
         movie_id: None,
@@ -41,11 +62,7 @@ async fn test_log_review_creates_movie_and_review() {
     let movies = InMemoryMovieRepository::new();
     let reviews = InMemoryReviewRepository::new();
     let events = NoopEventPublisher::new();
-    let ctx = TestContextBuilder::new()
-        .with_movies(Arc::clone(&movies) as _)
-        .with_reviews(Arc::clone(&reviews) as _)
-        .with_event_publisher(Arc::clone(&events) as _)
-        .build();
+    let ctx = build_ctx_with_real_logger(&movies, &reviews, &events);
 
     let user_id = uuid::Uuid::new_v4();
     let cmd = LogReviewCommand {
@@ -77,10 +94,8 @@ async fn test_log_review_reuses_existing_movie() {
     let movie_uuid = existing_movie.id().value();
     movies.upsert_movie(&existing_movie).await.unwrap();
 
-    let ctx = TestContextBuilder::new()
-        .with_movies(Arc::clone(&movies) as _)
-        .with_reviews(Arc::clone(&reviews) as _)
-        .build();
+    let events = NoopEventPublisher::new();
+    let ctx = build_ctx_with_real_logger(&movies, &reviews, &events);
 
     let cmd = LogReviewCommand {
         user_id: uuid::Uuid::new_v4(),
@@ -98,7 +113,10 @@ async fn test_log_review_reuses_existing_movie() {
 
 #[tokio::test]
 async fn test_log_review_with_invalid_rating_fails() {
-    let ctx = TestContextBuilder::new().build();
+    let movies = InMemoryMovieRepository::new();
+    let reviews = InMemoryReviewRepository::new();
+    let events = NoopEventPublisher::new();
+    let ctx = build_ctx_with_real_logger(&movies, &reviews, &events);
     let cmd = LogReviewCommand {
         user_id: uuid::Uuid::new_v4(),
         input: movie_input_manual("Some Film", 2000),

crates/application/src/diary/tests/review_logger.rs

@@ -0,0 +1,310 @@
+use std::sync::Arc;
+
+use async_trait::async_trait;
+use chrono::Utc;
+use domain::{
+    errors::DomainError,
+    models::Movie,
+    models::WatchlistEntry,
+    ports::{MetadataClient, MetadataSearchCriteria, MovieRepository, WatchlistRepository},
+    testing::{
+        FakeMetadataClient, InMemoryMovieRepository, InMemoryReviewRepository,
+        InMemoryWatchlistRepository, NoopEventPublisher,
+    },
+    value_objects::{ExternalMetadataId, MovieId, MovieTitle, PosterUrl, ReleaseYear, UserId},
+};
+use uuid::Uuid;
+
+use crate::diary::commands::{LogReviewCommand, MovieInput};
+use crate::diary::review_logger::DefaultReviewLogger;
+use crate::ports::ReviewLogger;
+
+fn make_logger(
+    movies: &Arc<InMemoryMovieRepository>,
+    reviews: &Arc<InMemoryReviewRepository>,
+    watchlist: &Arc<InMemoryWatchlistRepository>,
+    events: &Arc<NoopEventPublisher>,
+) -> DefaultReviewLogger {
+    DefaultReviewLogger::new(
+        Arc::clone(movies) as _,
+        Arc::clone(reviews) as _,
+        Arc::clone(watchlist) as _,
+        Arc::new(FakeMetadataClient) as _,
+        Arc::clone(events) as _,
+    )
+}
+
+#[tokio::test]
+async fn logs_review_with_manual_movie() {
+    let movies = InMemoryMovieRepository::new();
+    let reviews = InMemoryReviewRepository::new();
+    let watchlist = InMemoryWatchlistRepository::new();
+    let events = NoopEventPublisher::new();
+    let logger = make_logger(&movies, &reviews, &watchlist, &events);
+
+    let uid = Uuid::new_v4();
+    let cmd = LogReviewCommand {
+        user_id: uid,
+        input: MovieInput {
+            movie_id: None,
+            external_metadata_id: None,
+            manual_title: Some("Test Film".into()),
+            manual_release_year: Some(2024),
+            manual_director: None,
+        },
+        rating: 4,
+        comment: None,
+        watched_at: Utc::now().naive_utc(),
+    };
+
+    logger.log_review(cmd).await.unwrap();
+
+    assert_eq!(movies.count(), 1);
+    assert_eq!(reviews.count(), 1);
+}
+
+#[tokio::test]
+async fn removes_from_watchlist_on_review() {
+    let movies = InMemoryMovieRepository::new();
+    let reviews = InMemoryReviewRepository::new();
+    let watchlist = InMemoryWatchlistRepository::new();
+    let events = NoopEventPublisher::new();
+    let logger = make_logger(&movies, &reviews, &watchlist, &events);
+
+    let uid = Uuid::new_v4();
+    let user_id = UserId::from_uuid(uid);
+
+    // Create and store movie
+    let movie = Movie::new(
+        None,
+        MovieTitle::new("Watchlisted Film".into()).unwrap(),
+        ReleaseYear::new(2024).unwrap(),
+        None,
+        None,
+    );
+    let movie_id = movie.id().value();
+    movies.upsert_movie(&movie).await.unwrap();
+
+    // Add to watchlist
+    let entry = WatchlistEntry::new(user_id.clone(), MovieId::from_uuid(movie_id));
+    watchlist.add(&entry).await.unwrap();
+    assert_eq!(watchlist.count(), 1);
+
+    // Log review for same movie
+    let cmd = LogReviewCommand {
+        user_id: uid,
+        input: MovieInput {
+            movie_id: Some(movie_id),
+            external_metadata_id: None,
+            manual_title: None,
+            manual_release_year: None,
+            manual_director: None,
+        },
+        rating: 5,
+        comment: None,
+        watched_at: Utc::now().naive_utc(),
+    };
+
+    logger.log_review(cmd).await.unwrap();
+
+    assert_eq!(watchlist.count(), 0);
+}
+
+#[tokio::test]
+async fn logs_review_with_existing_movie_by_id() {
+    let movies = InMemoryMovieRepository::new();
+    let reviews = InMemoryReviewRepository::new();
+    let watchlist = InMemoryWatchlistRepository::new();
+    let events = NoopEventPublisher::new();
+    let logger = make_logger(&movies, &reviews, &watchlist, &events);
+
+    let movie = Movie::new(
+        None,
+        MovieTitle::new("Existing Film".into()).unwrap(),
+        ReleaseYear::new(2020).unwrap(),
+        None,
+        None,
+    );
+    let movie_uuid = movie.id().value();
+    movies.upsert_movie(&movie).await.unwrap();
+
+    let cmd = LogReviewCommand {
+        user_id: Uuid::new_v4(),
+        input: MovieInput {
+            movie_id: Some(movie_uuid),
+            external_metadata_id: None,
+            manual_title: None,
+            manual_release_year: None,
+            manual_director: None,
+        },
+        rating: 3,
+        comment: None,
+        watched_at: Utc::now().naive_utc(),
+    };
+
+    logger.log_review(cmd).await.unwrap();
+
+    assert_eq!(movies.count(), 1);
+    assert_eq!(reviews.count(), 1);
+}
+
+#[tokio::test]
+async fn existing_movie_not_found_returns_error() {
+    let movies = InMemoryMovieRepository::new();
+    let reviews = InMemoryReviewRepository::new();
+    let watchlist = InMemoryWatchlistRepository::new();
+    let events = NoopEventPublisher::new();
+    let logger = make_logger(&movies, &reviews, &watchlist, &events);
+
+    let cmd = LogReviewCommand {
+        user_id: Uuid::new_v4(),
+        input: MovieInput {
+            movie_id: Some(Uuid::new_v4()),
+            external_metadata_id: None,
+            manual_title: None,
+            manual_release_year: None,
+            manual_director: None,
+        },
+        rating: 4,
+        comment: None,
+        watched_at: Utc::now().naive_utc(),
+    };
+
+    assert!(logger.log_review(cmd).await.is_err());
+}
+
+#[tokio::test]
+async fn invalid_rating_returns_error() {
+    let movies = InMemoryMovieRepository::new();
+    let reviews = InMemoryReviewRepository::new();
+    let watchlist = InMemoryWatchlistRepository::new();
+    let events = NoopEventPublisher::new();
+    let logger = make_logger(&movies, &reviews, &watchlist, &events);
+
+    let cmd = LogReviewCommand {
+        user_id: Uuid::new_v4(),
+        input: MovieInput {
+            movie_id: None,
+            external_metadata_id: None,
+            manual_title: Some("Film".into()),
+            manual_release_year: Some(2024),
+            manual_director: None,
+        },
+        rating: 6,
+        comment: None,
+        watched_at: Utc::now().naive_utc(),
+    };
+
+    let result = logger.log_review(cmd).await;
+    assert!(result.is_err());
+    // No repo calls should have happened
+    assert_eq!(movies.count(), 0);
+    assert_eq!(reviews.count(), 0);
+}
+
+#[tokio::test]
+async fn watchlist_not_present_does_not_publish_removed() {
+    let movies = InMemoryMovieRepository::new();
+    let reviews = InMemoryReviewRepository::new();
+    let watchlist = InMemoryWatchlistRepository::new();
+    let events = NoopEventPublisher::new();
+    let logger = make_logger(&movies, &reviews, &watchlist, &events);
+
+    let cmd = LogReviewCommand {
+        user_id: Uuid::new_v4(),
+        input: MovieInput {
+            movie_id: None,
+            external_metadata_id: None,
+            manual_title: Some("No Watchlist Film".into()),
+            manual_release_year: Some(2024),
+            manual_director: None,
+        },
+        rating: 4,
+        comment: None,
+        watched_at: Utc::now().naive_utc(),
+    };
+
+    logger.log_review(cmd).await.unwrap();
+
+    let published = events.published();
+    assert!(
+        !published
+            .iter()
+            .any(|e| matches!(e, domain::events::DomainEvent::WatchlistEntryRemoved { .. })),
+        "should not publish WatchlistEntryRemoved when not on watchlist"
+    );
+}
+
+/// A metadata client that returns a movie with an external_metadata_id,
+/// triggering the MovieDiscovered event path.
+struct MetadataClientWithExternalId;
+
+#[async_trait]
+impl MetadataClient for MetadataClientWithExternalId {
+    async fn fetch_movie_metadata(
+        &self,
+        _criteria: &MetadataSearchCriteria,
+    ) -> Result<Movie, DomainError> {
+        Ok(Movie::new(
+            Some(ExternalMetadataId::new("tmdb:99999".into()).unwrap()),
+            MovieTitle::new("Discovered Film".into()).unwrap(),
+            ReleaseYear::new(2024).unwrap(),
+            None,
+            None,
+        ))
+    }
+
+    async fn get_poster_url(
+        &self,
+        _external_metadata_id: &ExternalMetadataId,
+    ) -> Result<Option<PosterUrl>, DomainError> {
+        Ok(None)
+    }
+}
+
+#[tokio::test]
+async fn publishes_movie_discovered_for_new_movie_with_external_id() {
+    let movies = InMemoryMovieRepository::new();
+    let reviews = InMemoryReviewRepository::new();
+    let watchlist = InMemoryWatchlistRepository::new();
+    let events = NoopEventPublisher::new();
+
+    let logger = DefaultReviewLogger::new(
+        Arc::clone(&movies) as _,
+        Arc::clone(&reviews) as _,
+        Arc::clone(&watchlist) as _,
+        Arc::new(MetadataClientWithExternalId) as _,
+        Arc::clone(&events) as _,
+    );
+
+    let cmd = LogReviewCommand {
+        user_id: Uuid::new_v4(),
+        input: MovieInput {
+            movie_id: None,
+            external_metadata_id: None,
+            manual_title: Some("Discovered Film".into()),
+            manual_release_year: Some(2024),
+            manual_director: None,
+        },
+        rating: 5,
+        comment: None,
+        watched_at: Utc::now().naive_utc(),
+    };
+
+    logger.log_review(cmd).await.unwrap();
+
+    let published = events.published();
+    assert!(
+        published
+            .iter()
+            .any(|e| matches!(e, domain::events::DomainEvent::MovieDiscovered { .. })),
+        "should publish MovieDiscovered for new movie with external_metadata_id"
+    );
+    assert!(
+        published.iter().any(|e| matches!(
+            e,
+            domain::events::DomainEvent::MovieEnrichmentRequested { .. }
+        )),
+        "should publish MovieEnrichmentRequested"
+    );
+}