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/get_activity_feed.rs

@@ -64,3 +64,7 @@ async fn build_following_filter(
         remote_actor_urls: remote_urls,
     })
 }
+
+#[cfg(test)]
+#[path = "tests/get_activity_feed.rs"]
+mod tests;

crates/application/src/diary/get_diary.rs

@@ -27,3 +27,7 @@ pub async fn execute(
 
     ctx.repos.diary.query_diary(&filter).await
 }
+
+#[cfg(test)]
+#[path = "tests/get_diary.rs"]
+mod tests;

crates/application/src/diary/get_movie_social_page.rs

@@ -43,3 +43,7 @@ pub async fn execute(
         profile,
     })
 }
+
+#[cfg(test)]
+#[path = "tests/get_movie_social_page.rs"]
+mod tests;

crates/application/src/diary/get_review_history.rs

@@ -21,3 +21,7 @@ pub async fn execute(
 
     Ok((history, trend))
 }
+
+#[cfg(test)]
+#[path = "tests/get_review_history.rs"]
+mod tests;

crates/application/src/diary/log_review.rs

@@ -1,98 +1,11 @@
-use domain::{
-    errors::DomainError,
-    events::DomainEvent,
-    models::{Movie, Review},
-    value_objects::{Comment, MovieId, Rating, UserId},
-};
+use domain::errors::DomainError;
 
-use crate::{
-    context::AppContext,
-    diary::commands::LogReviewCommand,
-    diary::movie_resolver::{MovieResolver, MovieResolverDeps},
-};
+use crate::{context::AppContext, diary::commands::LogReviewCommand};
 
 pub async fn execute(ctx: &AppContext, cmd: LogReviewCommand) -> Result<(), DomainError> {
-    let rating = Rating::new(cmd.rating)?;
-    let user_id = UserId::from_uuid(cmd.user_id);
-    let comment = cmd.comment.clone().map(Comment::new).transpose()?;
-
-    let (movie, is_new_movie) = if let Some(id) = cmd.input.movie_id {
-        let movie_id = MovieId::from_uuid(id);
-        let movie = ctx
-            .repos
-            .movie
-            .get_movie_by_id(&movie_id)
-            .await?
-            .ok_or_else(|| DomainError::NotFound(format!("Movie {id}")))?;
-        (movie, false)
-    } else {
-        let deps = MovieResolverDeps {
-            repository: ctx.repos.movie.as_ref(),
-            metadata_client: ctx.services.metadata.as_ref(),
-        };
-        MovieResolver::default_pipeline()
-            .resolve(&cmd.input, &deps)
-            .await?
-    };
-
-    ctx.repos.movie.upsert_movie(&movie).await?;
-
-    let review = Review::new(movie.id().clone(), user_id, rating, comment, cmd.watched_at)?;
-    let review_event = ctx.repos.review.save_review(&review).await?;
-
-    let was_on_watchlist = ctx
-        .repos
-        .watchlist
-        .remove_if_present(review.user_id(), review.movie_id())
-        .await?;
-    if was_on_watchlist {
-        let _ = ctx
-            .services
-            .event_publisher
-            .publish(&DomainEvent::WatchlistEntryRemoved {
-                user_id: review.user_id().clone(),
-                movie_id: review.movie_id().clone(),
-            })
-            .await;
-    }
-
-    publish_events(ctx, &movie, is_new_movie, review_event).await?;
-
-    Ok(())
+    ctx.services.review_logger.log_review(cmd).await
 }
 
 #[cfg(test)]
 #[path = "tests/log_review.rs"]
 mod tests;
-
-async fn publish_events(
-    ctx: &AppContext,
-    movie: &Movie,
-    is_new_movie: bool,
-    review_event: DomainEvent,
-) -> Result<(), DomainError> {
-    if is_new_movie && let Some(ext_id) = movie.external_metadata_id() {
-        let discovery_event = DomainEvent::MovieDiscovered {
-            movie_id: movie.id().clone(),
-            external_metadata_id: ext_id.clone(),
-        };
-        ctx.services
-            .event_publisher
-            .publish(&discovery_event)
-            .await?;
-    }
-
-    if let Some(ext_id) = movie.external_metadata_id() {
-        let enrichment_event = DomainEvent::MovieEnrichmentRequested {
-            movie_id: movie.id().clone(),
-            external_metadata_id: ext_id.value().to_string(),
-        };
-        ctx.services
-            .event_publisher
-            .publish(&enrichment_event)
-            .await?;
-    }
-
-    ctx.services.event_publisher.publish(&review_event).await?;
-    Ok(())
-}

crates/application/src/diary/mod.rs

@@ -8,3 +8,4 @@ pub mod get_review_history;
 pub mod log_review;
 pub mod movie_resolver;
 pub mod queries;
+pub mod review_logger;

crates/application/src/diary/review_logger.rs

@@ -0,0 +1,121 @@
+use std::sync::Arc;
+
+use async_trait::async_trait;
+use domain::{
+    errors::DomainError,
+    events::DomainEvent,
+    models::{Movie, Review},
+    ports::{
+        EventPublisher, MetadataClient, MovieRepository, ReviewRepository, WatchlistRepository,
+    },
+    value_objects::{Comment, MovieId, Rating, UserId},
+};
+
+use crate::diary::commands::LogReviewCommand;
+use crate::diary::movie_resolver::{MovieResolver, MovieResolverDeps};
+use crate::ports::ReviewLogger;
+
+pub struct DefaultReviewLogger {
+    movie_repo: Arc<dyn MovieRepository>,
+    review_repo: Arc<dyn ReviewRepository>,
+    watchlist_repo: Arc<dyn WatchlistRepository>,
+    metadata_client: Arc<dyn MetadataClient>,
+    event_publisher: Arc<dyn EventPublisher>,
+}
+
+impl DefaultReviewLogger {
+    pub fn new(
+        movie_repo: Arc<dyn MovieRepository>,
+        review_repo: Arc<dyn ReviewRepository>,
+        watchlist_repo: Arc<dyn WatchlistRepository>,
+        metadata_client: Arc<dyn MetadataClient>,
+        event_publisher: Arc<dyn EventPublisher>,
+    ) -> Self {
+        Self {
+            movie_repo,
+            review_repo,
+            watchlist_repo,
+            metadata_client,
+            event_publisher,
+        }
+    }
+}
+
+#[async_trait]
+impl ReviewLogger for DefaultReviewLogger {
+    async fn log_review(&self, cmd: LogReviewCommand) -> Result<(), DomainError> {
+        let rating = Rating::new(cmd.rating)?;
+        let user_id = UserId::from_uuid(cmd.user_id);
+        let comment = cmd.comment.clone().map(Comment::new).transpose()?;
+
+        let (movie, is_new_movie) = if let Some(id) = cmd.input.movie_id {
+            let movie_id = MovieId::from_uuid(id);
+            let movie = self
+                .movie_repo
+                .get_movie_by_id(&movie_id)
+                .await?
+                .ok_or_else(|| DomainError::NotFound(format!("Movie {id}")))?;
+            (movie, false)
+        } else {
+            let deps = MovieResolverDeps {
+                repository: self.movie_repo.as_ref(),
+                metadata_client: self.metadata_client.as_ref(),
+            };
+            MovieResolver::default_pipeline()
+                .resolve(&cmd.input, &deps)
+                .await?
+        };
+
+        self.movie_repo.upsert_movie(&movie).await?;
+
+        let review = Review::new(movie.id().clone(), user_id, rating, comment, cmd.watched_at)?;
+        let review_event = self.review_repo.save_review(&review).await?;
+
+        let was_on_watchlist = self
+            .watchlist_repo
+            .remove_if_present(review.user_id(), review.movie_id())
+            .await?;
+        if was_on_watchlist {
+            let _ = self
+                .event_publisher
+                .publish(&DomainEvent::WatchlistEntryRemoved {
+                    user_id: review.user_id().clone(),
+                    movie_id: review.movie_id().clone(),
+                })
+                .await;
+        }
+
+        publish_events(&self.event_publisher, &movie, is_new_movie, review_event).await
+    }
+}
+
+#[cfg(test)]
+#[path = "tests/review_logger.rs"]
+mod tests;
+
+async fn publish_events(
+    publisher: &Arc<dyn EventPublisher>,
+    movie: &Movie,
+    is_new_movie: bool,
+    review_event: DomainEvent,
+) -> Result<(), DomainError> {
+    if is_new_movie && let Some(ext_id) = movie.external_metadata_id() {
+        publisher
+            .publish(&DomainEvent::MovieDiscovered {
+                movie_id: movie.id().clone(),
+                external_metadata_id: ext_id.clone(),
+            })
+            .await?;
+    }
+
+    if let Some(ext_id) = movie.external_metadata_id() {
+        publisher
+            .publish(&DomainEvent::MovieEnrichmentRequested {
+                movie_id: movie.id().clone(),
+                external_metadata_id: ext_id.value().to_string(),
+            })
+            .await?;
+    }
+
+    publisher.publish(&review_event).await
+}

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"
+    );
+}