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/get_user_feed_test.rs

@@ -0,0 +1,72 @@
+use crate::support::register_command;
+use domain::testing::{test_movie_with_year, test_review};
+use std::sync::Arc;
+
+use uuid::Uuid;
+
+use domain::errors::DomainError;
+use domain::models::{DiaryEntry, collections::Paginated};
+use domain::testing::FakeDiaryQuery;
+use domain::value_objects::{Email, UserId};
+
+use crate::support::TestContextBuilder;
+use application::auth::deps::RegisterDeps;
+use application::auth::register;
+use application::diary::deps::GetUserFeedDeps;
+use application::diary::get_user_feed;
+
+async fn setup_user(b: &TestContextBuilder, email: &str, username: &str) {
+    let deps = RegisterDeps {
+        user: b.user_repo.clone(),
+        password_hasher: b.password_hasher.clone(),
+        config: b.config.clone(),
+    };
+    register::execute(&deps, register_command(email, username))
+        .await
+        .unwrap();
+}
+
+#[tokio::test]
+async fn user_feed_carries_author_and_entries() {
+    let b = TestContextBuilder::new();
+    setup_user(&b, "feed@test.com", "feeduser").await;
+
+    let email = Email::new("feed@test.com".into()).unwrap();
+    let user = b.user_repo.find_by_email(&email).await.unwrap().unwrap();
+    let uid = user.id().value();
+
+    let diary = FakeDiaryQuery::new();
+    let movie = test_movie_with_year("Feed Movie", 2020);
+    let review = test_review(movie.id(), &UserId::from_uuid(uid), 5);
+    diary.set_diary_page(Paginated {
+        items: vec![DiaryEntry::new(movie, review)],
+        total_count: 1,
+        limit: 50,
+        offset: 0,
+    });
+
+    let deps = GetUserFeedDeps {
+        user: b.user_repo.clone(),
+        diary: Arc::clone(&diary) as _,
+    };
+
+    let feed = get_user_feed::execute(&deps, uid, 50).await.unwrap();
+
+    assert_eq!(feed.author.display_name, "feed");
+    assert_eq!(feed.entries.len(), 1);
+}
+
+#[tokio::test]
+async fn user_feed_is_not_found_for_unknown_user() {
+    let b = TestContextBuilder::new();
+    let deps = GetUserFeedDeps {
+        user: b.user_repo.clone(),
+        diary: b.diary_repo.clone(),
+    };
+
+    let err = match get_user_feed::execute(&deps, Uuid::new_v4(), 50).await {
+        Err(e) => e,
+        Ok(_) => panic!("expected Err(NotFound) for an unknown user id, got Ok"),
+    };
+    assert!(matches!(err, DomainError::NotFound(_)));
+}