feat: complete leave approval MVP

ai-service/tests/test_leave_suggestion.py

@@ -0,0 +1,46 @@
+from datetime import datetime
+
+from fastapi.testclient import TestClient
+
+from app.main import app, get_gateway
+from app.models import LeaveDraftSuggestion, LeaveDraftSuggestionRequest, LeaveType
+
+
+class FakeGateway:
+    async def suggest(self, request: LeaveDraftSuggestionRequest) -> LeaveDraftSuggestion:
+        assert request.text == "明天下午请事假四小时"
+        return LeaveDraftSuggestion(
+            type=LeaveType.PERSONAL,
+            startsAt=datetime.fromisoformat("2026-07-19T13:30:00+08:00"),
+            endsAt=datetime.fromisoformat("2026-07-19T17:30:00+08:00"),
+            reason="办理个人事务",
+            assumptions=["下午按 13:30 开始计算"],
+        )
+
+
+def test_returns_structured_suggestion_without_executing_business_action() -> None:
+    app.dependency_overrides[get_gateway] = lambda: FakeGateway()
+    try:
+        response = TestClient(app).post(
+            "/v1/leave-drafts/suggest",
+            json={"text": "明天下午请事假四小时", "timezone": "Asia/Shanghai"},
+        )
+    finally:
+        app.dependency_overrides.clear()
+
+    assert response.status_code == 200
+    body = response.json()
+    assert body["suggestion"]["type"] == "PERSONAL"
+    assert body["requiresUserConfirmation"] is True
+    assert "applicantId" not in body["suggestion"]
+
+
+def test_rejects_invalid_time_range_from_model() -> None:
+    try:
+        LeaveDraftSuggestion(
+            startsAt=datetime.fromisoformat("2026-07-19T17:30:00+08:00"),
+            endsAt=datetime.fromisoformat("2026-07-19T13:30:00+08:00"),
+        )
+        assert False, "validation should fail"
+    except ValueError:
+        pass