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/person/get_credits_test.rs

@@ -0,0 +1,21 @@
+use domain::models::PersonId;
+use domain::testing::{FakePersonQuery, NoopEventPublisher};
+use std::sync::Arc;
+use uuid::Uuid;
+
+use application::person::{deps::GetPersonDeps, get_credits};
+
+#[tokio::test]
+async fn returns_empty_credits() {
+    let deps = GetPersonDeps {
+        person_query: Arc::new(FakePersonQuery),
+        event_publisher: NoopEventPublisher::new(),
+    };
+
+    let result = get_credits::execute(&deps, PersonId::from_uuid(Uuid::new_v4()))
+        .await
+        .unwrap();
+
+    assert!(result.cast.is_empty());
+    assert!(result.crew.is_empty());
+}

crates/application/tests/person/get_test.rs

@@ -0,0 +1,20 @@
+use domain::models::PersonId;
+use domain::testing::{FakePersonQuery, NoopEventPublisher};
+use std::sync::Arc;
+use uuid::Uuid;
+
+use application::person::{deps::GetPersonDeps, get};
+
+#[tokio::test]
+async fn returns_none_for_unknown_person() {
+    let deps = GetPersonDeps {
+        person_query: Arc::new(FakePersonQuery),
+        event_publisher: NoopEventPublisher::new(),
+    };
+
+    let result = get::execute(&deps, PersonId::from_uuid(Uuid::new_v4()))
+        .await
+        .unwrap();
+
+    assert!(result.is_none());
+}