[NX-501 Issue] Add E2E API smoke test workflow and related test suite

This commit introduces a GitHub Actions workflow for running E2E API smoke tests on main branches and pull requests. It includes a test suite covering authentication, CRUD operations, metrics access, and alerts status. The README is updated with instructions for running the tests locally.

backend/tests/e2e/test_api_smoke.py

@@ -0,0 +1,153 @@
+import asyncio
+import os
+from datetime import datetime, timedelta, timezone
+from uuid import uuid4
+
+from fastapi.testclient import TestClient
+
+from app.core.db import SessionLocal
+from app.main import app
+from app.models.models import Metric
+
+
+def _admin_credentials() -> tuple[str, str]:
+    return (
+        os.getenv("INIT_ADMIN_EMAIL", "admin@example.com"),
+        os.getenv("INIT_ADMIN_PASSWORD", "ChangeMe123!"),
+    )
+
+
+def _auth_headers(access_token: str) -> dict[str, str]:
+    return {"Authorization": f"Bearer {access_token}"}
+
+
+async def _insert_metric(target_id: int, metric_name: str, value: float) -> None:
+    async with SessionLocal() as db:
+        db.add(
+            Metric(
+                target_id=target_id,
+                ts=datetime.now(timezone.utc),
+                metric_name=metric_name,
+                value=value,
+                labels={},
+            )
+        )
+        await db.commit()
+
+
+def test_core_api_smoke_suite() -> None:
+    admin_email, admin_password = _admin_credentials()
+    unique = uuid4().hex[:8]
+    target_name = f"smoke-target-{unique}"
+    user_email = f"smoke-user-{unique}@example.com"
+
+    with TestClient(app) as client:
+        # Auth: login
+        login_res = client.post(
+            "/api/v1/auth/login",
+            json={"email": admin_email, "password": admin_password},
+        )
+        assert login_res.status_code == 200, login_res.text
+        tokens = login_res.json()
+        assert tokens.get("access_token")
+        assert tokens.get("refresh_token")
+        headers = _auth_headers(tokens["access_token"])
+
+        # Auth: me
+        me_res = client.get("/api/v1/me", headers=headers)
+        assert me_res.status_code == 200, me_res.text
+        assert me_res.json()["email"] == admin_email
+
+        # Targets: create
+        create_target_res = client.post(
+            "/api/v1/targets",
+            headers=headers,
+            json={
+                "name": target_name,
+                "host": "127.0.0.1",
+                "port": 5432,
+                "dbname": "postgres",
+                "username": "postgres",
+                "password": "postgres",
+                "sslmode": "disable",
+                "use_pg_stat_statements": False,
+                "owner_user_ids": [],
+                "tags": {"suite": "e2e-smoke"},
+            },
+        )
+        assert create_target_res.status_code == 201, create_target_res.text
+        target = create_target_res.json()
+        target_id = target["id"]
+
+        # Targets: list/get/update
+        list_targets_res = client.get("/api/v1/targets", headers=headers)
+        assert list_targets_res.status_code == 200, list_targets_res.text
+        assert any(item["id"] == target_id for item in list_targets_res.json())
+
+        get_target_res = client.get(f"/api/v1/targets/{target_id}", headers=headers)
+        assert get_target_res.status_code == 200, get_target_res.text
+
+        update_target_res = client.put(
+            f"/api/v1/targets/{target_id}",
+            headers=headers,
+            json={"name": f"{target_name}-updated"},
+        )
+        assert update_target_res.status_code == 200, update_target_res.text
+        assert update_target_res.json()["name"].endswith("-updated")
+
+        # Metrics access
+        asyncio.run(_insert_metric(target_id, "connections_total", 7.0))
+        now = datetime.now(timezone.utc)
+        from_ts = (now - timedelta(minutes=5)).isoformat()
+        to_ts = (now + timedelta(minutes=5)).isoformat()
+        metrics_res = client.get(
+            f"/api/v1/targets/{target_id}/metrics",
+            headers=headers,
+            params={"metric": "connections_total", "from": from_ts, "to": to_ts},
+        )
+        assert metrics_res.status_code == 200, metrics_res.text
+        assert isinstance(metrics_res.json(), list)
+        assert len(metrics_res.json()) >= 1
+
+        # Alerts status
+        alerts_status_res = client.get("/api/v1/alerts/status", headers=headers)
+        assert alerts_status_res.status_code == 200, alerts_status_res.text
+        payload = alerts_status_res.json()
+        assert "warnings" in payload
+        assert "alerts" in payload
+
+        # Admin users: list/create/update/delete
+        users_res = client.get("/api/v1/admin/users", headers=headers)
+        assert users_res.status_code == 200, users_res.text
+        assert isinstance(users_res.json(), list)
+
+        create_user_res = client.post(
+            "/api/v1/admin/users",
+            headers=headers,
+            json={
+                "email": user_email,
+                "first_name": "Smoke",
+                "last_name": "User",
+                "password": "SmokePass123!",
+                "role": "viewer",
+            },
+        )
+        assert create_user_res.status_code == 201, create_user_res.text
+        created_user_id = create_user_res.json()["id"]
+
+        update_user_res = client.put(
+            f"/api/v1/admin/users/{created_user_id}",
+            headers=headers,
+            json={"role": "operator", "first_name": "SmokeUpdated"},
+        )
+        assert update_user_res.status_code == 200, update_user_res.text
+        assert update_user_res.json()["role"] == "operator"
+
+        delete_user_res = client.delete(f"/api/v1/admin/users/{created_user_id}", headers=headers)
+        assert delete_user_res.status_code == 200, delete_user_res.text
+        assert delete_user_res.json().get("status") == "deleted"
+
+        # Cleanup target
+        delete_target_res = client.delete(f"/api/v1/targets/{target_id}", headers=headers)
+        assert delete_target_res.status_code == 200, delete_target_res.text
+        assert delete_target_res.json().get("status") == "deleted"