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/search/execute_test.rs

@@ -0,0 +1,20 @@
+use domain::models::SearchQuery;
+
+use crate::support::TestContextBuilder;
+use application::search::deps::SearchDeps;
+use application::search::execute;
+
+#[tokio::test]
+async fn returns_empty_results() {
+    let b = TestContextBuilder::new();
+    let deps = SearchDeps {
+        search_port: b.search_port.clone(),
+    };
+
+    let result = execute::execute(&deps, SearchQuery::default())
+        .await
+        .unwrap();
+
+    assert!(result.movies.items.is_empty());
+    assert!(result.people.items.is_empty());
+}