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/import/delete_profile_test.rs

@@ -0,0 +1,27 @@
+use std::sync::Arc;
+
+use domain::testing::InMemoryStore;
+use uuid::Uuid;
+
+use application::import::{
+    commands::DeleteImportProfileCommand, delete_profile, deps::DeleteImportProfileDeps,
+};
+
+#[tokio::test]
+async fn fails_when_profile_not_found() {
+    let profiles = InMemoryStore::new();
+    let deps = DeleteImportProfileDeps {
+        import_profile: Arc::clone(&profiles) as _,
+    };
+
+    let result = delete_profile::execute(
+        &deps,
+        DeleteImportProfileCommand {
+            user_id: Uuid::new_v4(),
+            profile_id: Uuid::new_v4(),
+        },
+    )
+    .await;
+
+    assert!(result.is_err());
+}