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/goals/update_test.rs

@@ -0,0 +1,59 @@
+use crate::support::{create_goal_command, update_goal_command};
+
+use crate::support::TestContextBuilder;
+use application::goals::deps::GoalCommandDeps;
+use application::goals::{create, update};
+
+#[tokio::test]
+async fn updates_target_count() {
+    let b = TestContextBuilder::new();
+    let deps = GoalCommandDeps {
+        goal_command: b.goal_command.clone(),
+        goal_query: b.goal_query.clone(),
+        stats: b.stats_repo.clone(),
+        event_publisher: b.event_publisher.clone(),
+    };
+
+    create::execute(&deps, create_goal_command(2025, 10))
+        .await
+        .unwrap();
+
+    let result = update::execute(&deps, update_goal_command(2025, 100))
+        .await
+        .unwrap();
+
+    assert_eq!(result.goal.target_count(), 100);
+}
+
+#[tokio::test]
+async fn fails_when_goal_not_found() {
+    let b = TestContextBuilder::new();
+    let deps = GoalCommandDeps {
+        goal_command: b.goal_command.clone(),
+        goal_query: b.goal_query.clone(),
+        stats: b.stats_repo.clone(),
+        event_publisher: b.event_publisher.clone(),
+    };
+    let result = update::execute(&deps, update_goal_command(2025, 10)).await;
+
+    assert!(result.is_err());
+}
+
+#[tokio::test]
+async fn rejects_zero_target() {
+    let b = TestContextBuilder::new();
+    let deps = GoalCommandDeps {
+        goal_command: b.goal_command.clone(),
+        goal_query: b.goal_query.clone(),
+        stats: b.stats_repo.clone(),
+        event_publisher: b.event_publisher.clone(),
+    };
+
+    create::execute(&deps, create_goal_command(2025, 10))
+        .await
+        .unwrap();
+
+    let result = update::execute(&deps, update_goal_command(2025, 0)).await;
+
+    assert!(result.is_err());
+}