Improve activity response metadata

tests/test_routes.py

@@ -8,6 +8,31 @@ from app.main import ActivityResult, app
 from app.settings import get_settings
 
 
+def test_activity_json_reports_stale_header(monkeypatch) -> None:
+    monkeypatch.setenv("GITHUB_USERNAME", "octocat")
+    monkeypatch.setenv("GITEA_BASE_URL", "https://gitea.example.com")
+    monkeypatch.setenv("GITEA_USERNAME", "octocat")
+    get_settings.cache_clear()
+
+    async def fake_collect_merged_activity(settings, cache, options):
+        return ActivityResult(
+            merged={"2026-01-01": {"github": 1, "gitea": 2, "total": 3}},
+            stale=True,
+            from_date=date(2026, 1, 1),
+            to_date=date(2026, 1, 1),
+            days_count=1,
+        )
+
+    monkeypatch.setattr("app.main.collect_merged_activity", fake_collect_merged_activity)
+
+    client = TestClient(app)
+    response = client.get("/activity.json")
+
+    assert response.status_code == 200
+    assert response.headers["x-activity-stale"] == "true"
+    assert response.json()["stale"] is True
+
+
 def test_activity_svg_returns_svg_content_type(monkeypatch) -> None:
     monkeypatch.setenv("GITHUB_USERNAME", "octocat")
     monkeypatch.setenv("GITEA_BASE_URL", "https://gitea.example.com")
@@ -35,4 +60,18 @@ def test_activity_svg_returns_svg_content_type(monkeypatch) -> None:
 
         assert response.status_code == 200
         assert response.headers["content-type"].startswith("image/svg+xml")
+        assert response.headers["x-activity-stale"] == "false"
         assert "<svg" in response.text
+
+
+def test_activity_json_rejects_year_and_days_together(monkeypatch) -> None:
+    monkeypatch.setenv("GITHUB_USERNAME", "octocat")
+    monkeypatch.setenv("GITEA_BASE_URL", "https://gitea.example.com")
+    monkeypatch.setenv("GITEA_USERNAME", "octocat")
+    get_settings.cache_clear()
+
+    client = TestClient(app)
+    response = client.get("/activity.json?year=2026&days=30")
+
+    assert response.status_code == 400
+    assert response.json() == {"detail": "Provide either year or days, not both"}