Strengthen is_connected with cached health probes.

Convert is_connected to a method that verifies backend liveness via TTL-cached ping (Redis) or bucket_exists (MinIO), with cache invalidation on connect/disconnect.

Co-authored-by: Cursor <[email protected]>

tests/unit/connection_health_test.py

@@ -0,0 +1,184 @@
+"""Tests for TTL-cached connection health checks on adapters."""
+
+from __future__ import annotations
+
+from unittest.mock import MagicMock, patch
+
+import pytest
+import redis
+
+from python_repositories.adapters.minio_adapter import MinioAdapter
+from python_repositories.adapters.redis_adapter import RedisAdapter
+
+
+@pytest.fixture
+def redis_adapter(monkeypatch: pytest.MonkeyPatch) -> RedisAdapter:
+    monkeypatch.setenv("REDIS_URI", "redis://localhost:6379")
+    return RedisAdapter()
+
+
+@pytest.fixture
+def minio_adapter(monkeypatch: pytest.MonkeyPatch) -> MinioAdapter:
+    monkeypatch.setenv("MINIO_ENDPOINT", "localhost:9000")
+    monkeypatch.setenv("MINIO_ACCESS_KEY", "minioadmin")
+    monkeypatch.setenv("MINIO_SECRET_KEY", "minioadmin")
+    monkeypatch.setenv("MINIO_BUCKET", "test-bucket")
+    return MinioAdapter()
+
+
+class TestRedisConnectionHealth:
+    def test_not_connected_when_no_client(self, redis_adapter: RedisAdapter) -> None:
+        assert not redis_adapter.is_connected()
+
+    def test_connected_when_probe_succeeds(self, redis_adapter: RedisAdapter) -> None:
+        mock_client = MagicMock(spec=redis.Redis)
+        mock_client.ping.return_value = True
+        redis_adapter._client = mock_client
+
+        assert redis_adapter.is_connected()
+        mock_client.ping.assert_called_once()
+
+    def test_stale_connection_when_probe_fails(
+        self, redis_adapter: RedisAdapter
+    ) -> None:
+        mock_client = MagicMock(spec=redis.Redis)
+        mock_client.ping.side_effect = redis.ConnectionError("connection lost")
+        redis_adapter._client = mock_client
+
+        assert not redis_adapter.is_connected()
+
+    def test_cache_hit_avoids_second_probe(self, redis_adapter: RedisAdapter) -> None:
+        mock_client = MagicMock(spec=redis.Redis)
+        mock_client.ping.return_value = True
+        redis_adapter._client = mock_client
+
+        with patch(
+            "python_repositories.adapters.redis_adapter.time.monotonic",
+            return_value=100.0,
+        ):
+            assert redis_adapter.is_connected()
+            assert redis_adapter.is_connected()
+
+        mock_client.ping.assert_called_once()
+
+    def test_cache_miss_runs_probe_again(self, redis_adapter: RedisAdapter) -> None:
+        mock_client = MagicMock(spec=redis.Redis)
+        mock_client.ping.return_value = True
+        redis_adapter._client = mock_client
+
+        with patch(
+            "python_repositories.adapters.redis_adapter.time.monotonic",
+            side_effect=[100.0, 102.0],
+        ):
+            assert redis_adapter.is_connected()
+            assert redis_adapter.is_connected()
+
+        assert mock_client.ping.call_count == 2
+
+    def test_disconnect_clears_cache(self, redis_adapter: RedisAdapter) -> None:
+        mock_client = MagicMock(spec=redis.Redis)
+        mock_client.ping.return_value = True
+        redis_adapter._client = mock_client
+
+        with patch(
+            "python_repositories.adapters.redis_adapter.time.monotonic",
+            return_value=100.0,
+        ):
+            assert redis_adapter.is_connected()
+
+        redis_adapter.disconnect()
+        redis_adapter._client = mock_client
+
+        with patch(
+            "python_repositories.adapters.redis_adapter.time.monotonic",
+            return_value=100.0,
+        ):
+            assert redis_adapter.is_connected()
+
+        assert mock_client.ping.call_count == 2
+
+
+class TestMinioConnectionHealth:
+    def test_not_connected_when_no_client(self, minio_adapter: MinioAdapter) -> None:
+        assert not minio_adapter.is_connected()
+
+    def test_not_connected_when_bucket_name_missing(
+        self, minio_adapter: MinioAdapter
+    ) -> None:
+        minio_adapter._client = MagicMock()
+        minio_adapter._bucket_name = None
+
+        assert not minio_adapter.is_connected()
+
+    def test_connected_when_probe_succeeds(self, minio_adapter: MinioAdapter) -> None:
+        mock_client = MagicMock()
+        mock_client.bucket_exists.return_value = True
+        minio_adapter._client = mock_client
+        minio_adapter._bucket_name = "test-bucket"
+
+        assert minio_adapter.is_connected()
+        mock_client.bucket_exists.assert_called_once_with("test-bucket")
+
+    def test_stale_connection_when_probe_fails(
+        self, minio_adapter: MinioAdapter
+    ) -> None:
+        mock_client = MagicMock()
+        mock_client.bucket_exists.side_effect = Exception("connection lost")
+        minio_adapter._client = mock_client
+        minio_adapter._bucket_name = "test-bucket"
+
+        assert not minio_adapter.is_connected()
+
+    def test_cache_hit_avoids_second_probe(self, minio_adapter: MinioAdapter) -> None:
+        mock_client = MagicMock()
+        mock_client.bucket_exists.return_value = True
+        minio_adapter._client = mock_client
+        minio_adapter._bucket_name = "test-bucket"
+
+        with patch(
+            "python_repositories.adapters.minio_adapter.time.monotonic",
+            return_value=100.0,
+        ):
+            assert minio_adapter.is_connected()
+            assert minio_adapter.is_connected()
+
+        mock_client.bucket_exists.assert_called_once()
+
+    def test_cache_miss_runs_probe_again(self, minio_adapter: MinioAdapter) -> None:
+        mock_client = MagicMock()
+        mock_client.bucket_exists.return_value = True
+        minio_adapter._client = mock_client
+        minio_adapter._bucket_name = "test-bucket"
+
+        with patch(
+            "python_repositories.adapters.minio_adapter.time.monotonic",
+            side_effect=[100.0, 102.0],
+        ):
+            assert minio_adapter.is_connected()
+            assert minio_adapter.is_connected()
+
+        assert mock_client.bucket_exists.call_count == 2
+
+    def test_disconnect_clears_cache(self, minio_adapter: MinioAdapter) -> None:
+        mock_client = MagicMock()
+        mock_client.bucket_exists.return_value = True
+        minio_adapter._client = mock_client
+        minio_adapter._bucket_name = "test-bucket"
+
+        with patch(
+            "python_repositories.adapters.minio_adapter.time.monotonic",
+            return_value=100.0,
+        ):
+            assert minio_adapter.is_connected()
+
+        minio_adapter.disconnect()
+        minio_adapter._client = mock_client
+        minio_adapter._bucket_name = "test-bucket"
+
+        with patch(
+            "python_repositories.adapters.minio_adapter.time.monotonic",
+            return_value=100.0,
+        ):
+            assert minio_adapter.is_connected()
+
+        assert mock_client.bucket_exists.call_count == 2