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/get_session_state_test.rs

@@ -0,0 +1,50 @@
+use std::sync::Arc;
+
+use uuid::Uuid;
+
+use domain::models::ImportSession;
+use domain::models::import::ParsedFile;
+use domain::ports::ImportSessionRepository;
+use domain::testing::InMemoryStore;
+use domain::value_objects::{ImportSessionId, UserId};
+
+use application::import::deps::GetSessionStateDeps;
+use application::import::get_session_state;
+
+#[tokio::test]
+async fn get_session_state_is_not_found_when_session_missing() {
+    let sessions = InMemoryStore::new();
+    let deps = GetSessionStateDeps {
+        import_session: Arc::clone(&sessions) as _,
+    };
+
+    let result =
+        get_session_state::execute(&deps, ImportSessionId::generate(), Uuid::new_v4()).await;
+
+    assert!(result.is_err());
+}
+
+#[tokio::test]
+async fn get_session_state_reports_columns_row_count_and_mapping_status() {
+    let sessions = InMemoryStore::new();
+    let user_id = Uuid::new_v4();
+    let mut session = ImportSession::new(UserId::from_uuid(user_id));
+    session.parsed_file = Some(ParsedFile {
+        columns: vec!["Name".into()],
+        rows: vec![vec!["a".into()], vec!["b".into()]],
+    });
+    let session_id = session.id.clone();
+    sessions.create(&session).await.unwrap();
+
+    let deps = GetSessionStateDeps {
+        import_session: Arc::clone(&sessions) as _,
+    };
+
+    let state = get_session_state::execute(&deps, session_id, user_id)
+        .await
+        .unwrap();
+
+    assert_eq!(state.columns, vec!["Name".to_string()]);
+    assert_eq!(state.row_count, 2);
+    assert!(!state.has_mappings);
+}