baseline: 批次A-D 成果 + membership 半成品（测试红）

backend/tests/test_ping.py

@@ -0,0 +1,16 @@
+"""ping endpoint 集成测试：同步 client + adrf async view。"""
+
+import pytest
+from django.test import Client
+
+
+@pytest.mark.django_db
+def test_ping_returns_ok():
+    client = Client()
+    response = client.get("/api/v1/ping/")
+    assert response.status_code == 200
+    data = response.json()
+    assert data["ok"] is True
+    assert data["service"] == "dealerhub"
+    assert "django" in data["versions"]
+    assert "granian" in data["versions"]