refactor: move domain inline tests to separate files under tests/

Match the application crate convention: each source file references its
tests via #[cfg(test)] #[path = "tests/filename.rs"] mod tests; with
the test code in a sibling tests/ directory.

- events.rs       -> tests/events.rs
- value_objects.rs -> tests/value_objects.rs
- models/mod.rs   -> models/tests/mod.rs  (renamed from tests.rs)
- models/person.rs -> models/tests/person.rs
- models/goal.rs   -> models/tests/goal.rs
- models/watch_event.rs -> models/tests/watch_event.rs
- services/review_history.rs -> services/tests/review_history.rs

crates/domain/src/services/review_history.rs

@@ -53,81 +53,5 @@ impl ReviewHistoryAnalyzer {
 }
 
 #[cfg(test)]
-mod tests {
-    use super::*;
-    use crate::models::{Movie, Review, ReviewHistory};
-    use crate::value_objects::{MovieId, MovieTitle, Rating, ReleaseYear, UserId};
-    use chrono::{NaiveDate, NaiveDateTime, NaiveTime};
-
-    fn make_movie() -> Movie {
-        Movie::new(
-            None,
-            MovieTitle::new("Test".into()).unwrap(),
-            ReleaseYear::new(2024).unwrap(),
-            None,
-            None,
-        )
-    }
-
-    fn dt(year: i32, month: u32, day: u32) -> NaiveDateTime {
-        NaiveDateTime::new(
-            NaiveDate::from_ymd_opt(year, month, day).unwrap(),
-            NaiveTime::from_hms_opt(12, 0, 0).unwrap(),
-        )
-    }
-
-    fn review_with_rating(movie_id: &MovieId, rating: u8, watched_at: NaiveDateTime) -> Review {
-        let user_id = UserId::generate();
-        Review::new(
-            movie_id.clone(),
-            user_id,
-            Rating::new(rating).unwrap(),
-            None,
-            watched_at,
-        )
-        .unwrap()
-    }
-
-    #[test]
-    fn neutral_when_empty() {
-        let movie = make_movie();
-        let history = ReviewHistory::new(movie, vec![]);
-        let trend = ReviewHistoryAnalyzer::rating_trend(&history).unwrap();
-        assert_eq!(trend, Trend::Neutral);
-    }
-
-    #[test]
-    fn neutral_when_single_review() {
-        let movie = make_movie();
-        let r = review_with_rating(movie.id(), 4, dt(2024, 1, 1));
-        let history = ReviewHistory::new(movie, vec![r]);
-        let trend = ReviewHistoryAnalyzer::rating_trend(&history).unwrap();
-        assert_eq!(trend, Trend::Neutral);
-    }
-
-    #[test]
-    fn improved_when_latest_above_average() {
-        let movie = make_movie();
-        let viewings = vec![
-            review_with_rating(movie.id(), 2, dt(2024, 1, 1)),
-            review_with_rating(movie.id(), 3, dt(2024, 2, 1)),
-            review_with_rating(movie.id(), 5, dt(2024, 3, 1)),
-        ];
-        let history = ReviewHistory::new(movie, viewings);
-        let trend = ReviewHistoryAnalyzer::rating_trend(&history).unwrap();
-        assert_eq!(trend, Trend::Improved);
-    }
-
-    #[test]
-    fn declined_when_latest_below_average() {
-        let movie = make_movie();
-        let viewings = vec![
-            review_with_rating(movie.id(), 5, dt(2024, 1, 1)),
-            review_with_rating(movie.id(), 4, dt(2024, 2, 1)),
-            review_with_rating(movie.id(), 2, dt(2024, 3, 1)),
-        ];
-        let history = ReviewHistory::new(movie, viewings);
-        let trend = ReviewHistoryAnalyzer::rating_trend(&history).unwrap();
-        assert_eq!(trend, Trend::Declined);
-    }
-}
+#[path = "tests/review_history.rs"]
+mod tests;

crates/domain/src/services/tests/review_history.rs

@@ -0,0 +1,76 @@
+use super::*;
+use crate::models::{Movie, Review, ReviewHistory};
+use crate::value_objects::{MovieId, MovieTitle, Rating, ReleaseYear, UserId};
+use chrono::{NaiveDate, NaiveDateTime, NaiveTime};
+
+fn make_movie() -> Movie {
+    Movie::new(
+        None,
+        MovieTitle::new("Test".into()).unwrap(),
+        ReleaseYear::new(2024).unwrap(),
+        None,
+        None,
+    )
+}
+
+fn dt(year: i32, month: u32, day: u32) -> NaiveDateTime {
+    NaiveDateTime::new(
+        NaiveDate::from_ymd_opt(year, month, day).unwrap(),
+        NaiveTime::from_hms_opt(12, 0, 0).unwrap(),
+    )
+}
+
+fn review_with_rating(movie_id: &MovieId, rating: u8, watched_at: NaiveDateTime) -> Review {
+    let user_id = UserId::generate();
+    Review::new(
+        movie_id.clone(),
+        user_id,
+        Rating::new(rating).unwrap(),
+        None,
+        watched_at,
+    )
+    .unwrap()
+}
+
+#[test]
+fn neutral_when_empty() {
+    let movie = make_movie();
+    let history = ReviewHistory::new(movie, vec![]);
+    let trend = ReviewHistoryAnalyzer::rating_trend(&history).unwrap();
+    assert_eq!(trend, Trend::Neutral);
+}
+
+#[test]
+fn neutral_when_single_review() {
+    let movie = make_movie();
+    let r = review_with_rating(movie.id(), 4, dt(2024, 1, 1));
+    let history = ReviewHistory::new(movie, vec![r]);
+    let trend = ReviewHistoryAnalyzer::rating_trend(&history).unwrap();
+    assert_eq!(trend, Trend::Neutral);
+}
+
+#[test]
+fn improved_when_latest_above_average() {
+    let movie = make_movie();
+    let viewings = vec![
+        review_with_rating(movie.id(), 2, dt(2024, 1, 1)),
+        review_with_rating(movie.id(), 3, dt(2024, 2, 1)),
+        review_with_rating(movie.id(), 5, dt(2024, 3, 1)),
+    ];
+    let history = ReviewHistory::new(movie, viewings);
+    let trend = ReviewHistoryAnalyzer::rating_trend(&history).unwrap();
+    assert_eq!(trend, Trend::Improved);
+}
+
+#[test]
+fn declined_when_latest_below_average() {
+    let movie = make_movie();
+    let viewings = vec![
+        review_with_rating(movie.id(), 5, dt(2024, 1, 1)),
+        review_with_rating(movie.id(), 4, dt(2024, 2, 1)),
+        review_with_rating(movie.id(), 2, dt(2024, 3, 1)),
+    ];
+    let history = ReviewHistory::new(movie, viewings);
+    let trend = ReviewHistoryAnalyzer::rating_trend(&history).unwrap();
+    assert_eq!(trend, Trend::Declined);
+}