added minio adapter and tests

python_repositories/adapters/minio_adapter.py

@@ -0,0 +1,202 @@
+"""Definition of MinioAdapter class."""
+
+from __future__ import annotations
+import os
+from io import BytesIO
+
+import structlog
+from minio import Minio, S3Error
+
+from python_utils import check_env
+
+from python_repositories.interfaces import (
+    ContextAwareInterface,
+    ConnectionAwareInterface,
+)
+
+
+class MinioAdapter(
+    ContextAwareInterface,
+    ConnectionAwareInterface,
+):
+    """Minio adapter exposing basic CRUD functionality."""
+
+    endpoint_env_var_name: str = "MINIO_ENDPOINT"
+    access_key_env_var_name: str = "MINIO_ACCESS_KEY"
+    secret_key_env_var_name: str = "MINIO_SECRET_KEY"
+    bucket_env_var_name: str = "MINIO_BUCKET"
+    chunk_size: int = 5*2**20  # 5 MiB
+
+    def __init__(self) -> None:
+        # Setup logger
+        self.logger = structlog.get_logger(
+            self.__class__.__name__,
+        )
+        # Check environment variables
+        check_env(
+            {
+                self.endpoint_env_var_name,
+                self.access_key_env_var_name,
+                self.secret_key_env_var_name,
+                self.bucket_env_var_name,
+            },
+        )
+        # Prepare internal variables
+        self._client: Minio | None = None
+        self._bucket_name: str | None = None
+
+    def __enter__(self) -> MinioAdapter:
+        """Enter the context."""
+        self.connect()
+        return self
+
+    def __exit__(
+        self, exc_type: type | None, exc_val: object | None, exc_tb: object | None
+    ) -> None:
+        """Exit the context."""
+        ctx_info = {"exc_type": exc_type, "exc_val": exc_val, "exc_tb": exc_tb}
+        if any(
+            (
+                exc_type is not None,
+                exc_val is not None,
+                exc_tb is not None,
+            ),
+        ):
+            self.logger.error("Error while exiting context", **ctx_info)
+        self.disconnect()
+
+    def connect(self) -> None:
+        """Connect to the Minio server."""
+        # Stop if already connected
+        if self.is_connected:
+            self.logger.info("Already connected to Minio")
+            return
+        # Prepare arguments
+        endpoint = str(os.getenv(self.endpoint_env_var_name))
+        access_key = str(os.getenv(self.access_key_env_var_name))
+        secret_key = str(os.getenv(self.secret_key_env_var_name))
+        bucket = str(os.getenv(self.bucket_env_var_name))
+        # Connect client
+        client = Minio(
+            endpoint=endpoint,
+            access_key=access_key,
+            secret_key=secret_key,
+            secure=False,
+        )
+        # Test the connection by listing buckets (will raise if connection fails)
+        try:
+            _ = client.list_buckets()
+        except Exception as exc:  # pylint: disable=broad-except
+            raise ConnectionError(f"Could not connect to Minio at {endpoint}") from exc
+        # Ensure bucket exists
+        if not client.bucket_exists(bucket):
+            self.logger.info(f"Creating bucket '{bucket}'")
+            client.make_bucket(bucket)
+        # Persist information
+        self._client = client
+        self._bucket_name = bucket
+
+    def disconnect(self) -> None:
+        """Disconnect from the Minio server."""
+        # Close connection
+        # N.B. Minio client does not have a close method, but we include this for symmetry with other adapters
+        # Reset client
+        self._client = None
+        self._bucket_name = None
+
+    @property
+    def is_connected(self) -> bool:
+        """Check if connected to Minio server."""
+        res = bool(isinstance(self._client, Minio))
+        self.logger.debug(res)
+        return res
+
+    def _put(self, object_name: str, data: BytesIO) -> None:
+        """Put an object into the Minio bucket."""
+        # Check input
+        if not isinstance(object_name, str) or len(object_name) == 0:
+            raise ValueError("object_name must be a non-empty string")
+        if not isinstance(data, BytesIO) or data.getbuffer().nbytes == 0:
+            raise ValueError("data must be a non-empty BytesIO object")
+        # Check connection
+        if self._client is None or not self.is_connected:
+            raise ConnectionError("Not connected to Minio")
+        # Prepare buffer for reading
+        num_bytes = data.getbuffer().nbytes
+        data.seek(0)
+        # Send data to bucket
+        # N.B. bucket name is set when connecting
+        self._client.put_object(
+            bucket_name=self._bucket_name,  # type: ignore
+            object_name=object_name,
+            data=data,
+            length=num_bytes,
+            part_size=self.chunk_size,
+        )
+        self.logger.debug(f"Put object '{object_name}' into bucket '{self._bucket_name}'")
+
+    def _get(self, object_name: str) -> BytesIO | None:
+        """Get an object from the Minio bucket."""
+        # Check input
+        if not isinstance(object_name, str) or len(object_name) == 0:
+            raise ValueError("object_name must be a non-empty string")
+        # Check connection
+        if self._client is None or not self.is_connected:
+            raise ConnectionError("Not connected to Minio")
+        # Get data from bucket
+        # N.B. bucket name is set when connecting
+        try:
+            response = self._client.get_object(
+                bucket_name=self._bucket_name,  # type: ignore
+                object_name=object_name,
+            )
+            # Get buffered data
+            buffer = BytesIO()
+            while chunk := response.read(self.chunk_size):
+                buffer.write(chunk)
+            buffer.seek(0)
+            self.logger.debug(f"Got object '{object_name}' from bucket '{self._bucket_name}'")
+            return buffer
+        except S3Error as exc:
+            if exc.code == "NoSuchKey":
+                self.logger.warning(f"Object '{object_name}' not found in bucket '{self._bucket_name}'")
+            else:
+                self.logger.error(repr(exc))
+        except Exception as exc:  # pylint: disable=broad-except
+            self.logger.error(repr(exc))
+        return None
+
+    def _delete(self, object_name: str) -> None:
+        """Delete an object from the Minio bucket."""
+        # Check input
+        if not isinstance(object_name, str) or len(object_name) == 0:
+            raise ValueError("object_name must be a non-empty string")
+        # Check connection
+        if self._client is None or not self.is_connected:
+            raise ConnectionError("Not connected to Minio")
+        # Delete object from bucket
+        # N.B. bucket name is set when connecting
+        self._client.remove_object(
+            bucket_name=self._bucket_name,  # type: ignore
+            object_name=object_name,
+        )
+        self.logger.debug(f"Deleted object '{object_name}' from bucket '{self._bucket_name}'")
+
+    def _list_objects(self, prefix: str = "") -> list[str]:
+        """List objects in the Minio bucket with an optional prefix."""
+        # Check input
+        if not isinstance(prefix, str):
+            raise ValueError("prefix must be a string")
+        # Check connection
+        # N.B. bucket name is set when connecting
+        if self._client is None or not self.is_connected:
+            raise ConnectionError("Not connected to Minio")
+        # List objects in bucket
+        objects = self._client.list_objects(
+            bucket_name=self._bucket_name,  # type: ignore
+            prefix=prefix,
+            recursive=True,
+        )
+        object_names = [obj.object_name for obj in objects if obj.object_name is not None]
+        self.logger.debug(f"Listed {len(object_names)} object(s) in bucket '{self._bucket_name}' with prefix '{prefix}'")
+        return object_names

tests/integration/conftest.py

@@ -6,8 +6,14 @@ import pytest
 import redis
 import structlog
 import logging
+from minio import Minio
 
 from testcontainers.redis import RedisContainer
+from testcontainers.minio import MinioContainer
+
+MINIO_ACCESS_KEY = "minioadmin"
+MINIO_SECRET_KEY = "minioadmin"
+MINIO_BUCKET = "test-bucket"
 
 
 @pytest.fixture(scope="session", autouse=True)
@@ -16,6 +22,10 @@ def configure_logging() -> None:
     # Configure structlog
     structlog.configure(
         processors=[
+            structlog.stdlib.filter_by_level,
+            structlog.stdlib.add_logger_name,
+            structlog.stdlib.add_log_level,
+            structlog.processors.TimeStamper(fmt="iso"),
             structlog.processors.JSONRenderer(),
         ],
         logger_factory=structlog.stdlib.LoggerFactory(),
@@ -27,12 +37,11 @@ def configure_logging() -> None:
 
 
 @pytest.fixture(scope="session")
-def redis_container() -> Generator[str]:
+def redis_container() -> Generator[str, None, None]:
     """Set up a Redis container for testing and yield the Redis URI."""
     # Start container
     container = RedisContainer(
         image="redis/redis-stack:7.2.0-v0",
-        port=6379,
     )
     container.start()
     # Set environment variable for Redis URI
@@ -46,13 +55,42 @@ def redis_container() -> Generator[str]:
     container.stop()
 
 
+@pytest.fixture(scope="session")
+def minio_container() -> Generator[dict[str, str], None, None]:
+    """Set up a Minio container for testing and yield the Minio URI."""
+    # Start container
+    container = MinioContainer(
+        image="minio/minio:latest",
+        access_key=MINIO_ACCESS_KEY,
+        secret_key=MINIO_SECRET_KEY,
+    )
+    container.start()
+    # Build environment variables dictionary
+    minio_host = container.get_container_host_ip()
+    minio_port = container.get_exposed_port(9000)
+    minio_endpoint = f"{minio_host}:{minio_port}"
+    env_vars = {
+        "MINIO_ENDPOINT": minio_endpoint,
+        "MINIO_ACCESS_KEY": MINIO_ACCESS_KEY,
+        "MINIO_SECRET_KEY": MINIO_SECRET_KEY,
+        "MINIO_BUCKET": MINIO_BUCKET,
+    }
+
+    yield env_vars
+
+    # Stop container
+    container.stop()
+
+
 @pytest.fixture(scope="session", autouse=True)
 def set_environment_variables(
     redis_container: str,
+    minio_container: dict[str, str],
 ) -> Generator[dict[str, str]]:
     """Set environment variables needed for tests."""
     # Build environment variables dictionary
     env_vars = {"REDIS_URI": redis_container}
+    env_vars.update(minio_container)
     # Set environment variables
     for key, value in env_vars.items():
         os.environ[key] = value
@@ -78,3 +116,26 @@ def raw_redis_client(redis_container: str) -> Generator[redis.Redis]:
     # Cleanup
     client.flushall()
     client.close()
+
+
+@pytest.fixture(scope="session")
+def raw_minio_client(minio_container: dict[str, str]) -> Generator[Minio]:
+    """Provide a raw Minio client connected to the test Minio container."""
+    # Connect client
+    client = Minio(
+        endpoint=minio_container["MINIO_ENDPOINT"],
+        access_key=minio_container["MINIO_ACCESS_KEY"],
+        secret_key=minio_container["MINIO_SECRET_KEY"],
+        secure=False,
+    )
+    # Ensure bucket exists
+    bucket_name = minio_container["MINIO_BUCKET"]
+    if not client.bucket_exists(bucket_name):
+        client.make_bucket(bucket_name)
+
+    yield client
+
+    # Cleanup
+    objects = client.list_objects(bucket_name, recursive=True)
+    for obj in objects:
+        client.remove_object(bucket_name, obj.object_name)

tests/integration/minio_adapter_test.py

@@ -0,0 +1,467 @@
+# pylint: disable=protected-access
+# The above line disables pylint's protected member access warnings for this file,
+# allowing tests to access MinioAdapter's internal methods as needed for integration testing.
+"""Integration tests for the MinioAdapter."""
+
+from collections.abc import Generator
+from minio import S3Error
+import pytest
+from unittest.mock import MagicMock, patch
+from minio import Minio
+from io import BytesIO
+import random
+import os
+import logging
+from python_repositories.adapters.minio_adapter import MinioAdapter
+
+
+def same_data(
+    data_a: BytesIO,
+    data_b: BytesIO,
+) -> bool:
+    """Check if two BytesIO-objects contain the same data."""
+    assert isinstance(data_a, BytesIO)
+    assert isinstance(data_b, BytesIO)
+    # prepare for being read
+    data_a.seek(0)
+    data_b.seek(0)
+    # convert to bytes
+    data_a_bytes = data_a.read()
+    data_b_bytes = data_b.read()
+    # compare size
+    if len(data_a_bytes) != len(data_b_bytes):
+        logging.error(
+            'data has different length: %s and %s',
+            len(data_a_bytes),
+            len(data_b_bytes),
+        )
+        return False
+    # compare content
+    if data_a_bytes != data_b_bytes:
+        logging.error('data has different bytes')
+        return False
+    return True
+
+
+@pytest.fixture(scope="module")
+def data() -> Generator[BytesIO]:
+    """Provide a sample data bytes for tests."""
+    # Generate random bytes
+    random_bytes = random.randbytes(2**21)  # 2 MiB
+    yield BytesIO(random_bytes)
+
+
+@pytest.fixture(scope="function")
+def data_in_minio(
+    raw_minio_client: Minio,
+    data: BytesIO,
+) -> Generator[tuple[str, BytesIO]]:
+    """Fixture to set up a known value in Minio before each test."""
+    object_name = "test_object"
+    bucket_name = str(os.getenv("MINIO_BUCKET"))
+    # Upload object
+    num_bytes = data.getbuffer().nbytes
+    data.seek(0)
+    raw_minio_client.put_object(
+        bucket_name,
+        object_name,
+        data,
+        length=num_bytes,
+        part_size=MinioAdapter.chunk_size,
+    )
+    # Reset data for reading in tests
+    data.seek(0)
+
+    yield object_name, data
+
+    # Cleanup
+    raw_minio_client.remove_object(bucket_name, object_name)
+
+
+@pytest.fixture(scope="module")
+def minio_adapter() -> Generator[MinioAdapter]:
+    """Fixture to provide a connected MinioAdapter instance."""
+    adapter = MinioAdapter()
+    adapter.connect()
+    yield adapter
+    adapter.disconnect()
+
+
+@pytest.fixture(scope="function", autouse=True)
+def clear_minio(
+    raw_minio_client: Minio,
+) -> None:
+    """Fixture to clear all Minio objects before each test."""
+    bucket_name = str(os.getenv("MINIO_BUCKET"))
+    # Clear all objects before each test
+    objects = raw_minio_client.list_objects(bucket_name, recursive=True)
+    for obj in objects:
+        if not obj.object_name:
+            continue
+        raw_minio_client.remove_object(bucket_name, obj.object_name)
+
+
+def test_should_adhere_to_interface() -> None:
+    """Test that the MinioAdapter adheres to the expected interface."""
+    # Instantiation fails if interface not adhered to
+    _ = MinioAdapter()
+
+
+def test_should_have_logger_when_instantiated() -> None:
+    """Test that the MinioAdapter has a logger when instantiated."""
+    adapter = MinioAdapter()
+    assert hasattr(adapter, "logger")
+
+
+def test_should_not_be_connected_when_instantiated() -> None:
+    """Test that the MinioAdapter is not connected when instantiated."""
+    adapter = MinioAdapter()
+    assert not adapter.is_connected
+
+
+def test_should_log_info_when_already_connected(
+    minio_adapter: MinioAdapter,
+    caplog: pytest.LogCaptureFixture,
+) -> None:
+    """Test that the MinioAdapter logs info when connect is called while already connected."""
+    with caplog.at_level(logging.INFO):
+        minio_adapter.connect()
+    assert "Already connected to Minio" in caplog.text
+
+
+def test_should_raise_connection_error_when_unable_to_connect(
+    monkeypatch: pytest.MonkeyPatch,
+) -> None:
+    """Test that the MinioAdapter raises a ConnectionError when unable to connect."""
+    # Arrange
+    monkeypatch.setenv("MINIO_ENDPOINT", "invalid_uri")
+    adapter = MinioAdapter()
+    with pytest.raises(ConnectionError):
+        adapter.connect()
+    assert not adapter.is_connected
+
+
+def test_should_log_info_when_creating_expected_bucket(
+    raw_minio_client: Minio,
+    caplog: pytest.LogCaptureFixture,
+) -> None:
+    """Test that the MinioAdapter logs info when creating the expected bucket."""
+    # Arrange
+    bucket_name = str(os.getenv("MINIO_BUCKET"))
+    raw_minio_client.remove_bucket(bucket_name)
+    adapter = MinioAdapter()
+    # Act
+    with caplog.at_level(logging.INFO):
+        adapter.connect()
+    # Assert
+    assert f"Creating bucket '{bucket_name}'" in caplog.text
+
+
+def test_should_log_error_on_exception_during_exit(
+    minio_container: dict[str, str],
+    caplog: pytest.LogCaptureFixture,
+) -> None:
+    """Test that the MinioAdapter logs an error if an exception occurs during __exit__."""
+    try:
+        with MinioAdapter() as adapter:
+            assert adapter.is_connected
+            raise ValueError("Simulated error")
+    except ValueError:
+        pass  # Expected
+    # Assert error was logged
+    assert "Error while exiting context" in caplog.text
+
+
+def test_should_have_context_manager() -> None:
+    """Test that the MinioAdapter can be used as a context manager."""
+    with MinioAdapter() as adapter:
+        assert adapter._client is not None
+    assert adapter._client is None
+
+
+def test_should_get_data(
+    data_in_minio: tuple[str, BytesIO],
+    minio_adapter: MinioAdapter,
+) -> None:
+    """Test that the MinioAdapter can get data from a bucket."""
+    # Arrange
+    object_name, expected_data = data_in_minio
+    # Act
+    received_data = minio_adapter._get(object_name)  # type: ignore
+    # Assert
+    assert received_data is not None
+    assert same_data(expected_data, received_data)
+
+
+def test_should_get_none_for_nonexistent_object(
+    minio_adapter: MinioAdapter,
+) -> None:
+    """Test that the MinioAdapter returns None for a nonexistent object."""
+    # Arrange
+    object_name = "nonexistent_object"
+    # Act
+    received_data = minio_adapter._get(object_name)  # type: ignore
+    # Assert
+    assert received_data is None
+
+
+def test_should_raise_value_error_on_invalid_get_object_name(
+    minio_adapter: MinioAdapter,
+) -> None:
+    """Test that the MinioAdapter raises ValueError when getting with an invalid object name."""
+    # Arrange
+    invalid_object_names = ["", 123, None]
+    # Act & Assert
+    for object_name in invalid_object_names:
+        with pytest.raises(ValueError):
+            minio_adapter._get(object_name)  # type: ignore
+
+
+def test_should_raise_connection_error_on_get_when_not_connected(
+    minio_adapter: MinioAdapter,
+) -> None:
+    """Test that the MinioAdapter raises ConnectionError when getting while not connected."""
+    # Arrange
+    adapter = MinioAdapter()  # not connected
+    # Act & Assert
+    with pytest.raises(ConnectionError):
+        adapter._get("some_object")  # type: ignore
+
+
+def test_should_log_warning_when_getting_nonexistent_object(
+    caplog: pytest.LogCaptureFixture,
+) -> None:
+    """Test that the MinioAdapter logs a warning when getting a nonexistent object."""
+    # Arrange
+    adapter = MinioAdapter()
+    adapter._client = MagicMock(spec=Minio)
+    adapter._client.get_object.side_effect = S3Error(code="NoSuchKey", message="", resource="", request_id="", host_id="", response="", bucket_name="test-bucket", object_name="missing-object")
+    adapter._bucket_name = "test-bucket"
+    object_name = "missing-object"
+    # Act
+    with caplog.at_level("WARNING"):
+        result = adapter._get(object_name)
+    # Assert
+    assert result is None
+    assert f"Object '{object_name}' not found in bucket '{adapter._bucket_name}'" in caplog.text
+
+
+def test_should_log_error_when_getting_with_s3error_other_than_no_such_key(
+    caplog: pytest.LogCaptureFixture,
+) -> None:
+    """Test that the MinioAdapter logs an error when getting a nonexistent object."""
+    # Arrange
+    adapter = MinioAdapter()
+    adapter._client = MagicMock(spec=Minio)
+    other_s3error = S3Error(code="UnhandledError", message="", resource="", request_id="", host_id="", response="", bucket_name="test-bucket", object_name="missing-object")
+    adapter._client.get_object.side_effect = other_s3error
+    adapter._bucket_name = "test-bucket"
+    object_name = "missing-object"
+    # Act
+    with caplog.at_level("ERROR"):
+        result = adapter._get(object_name)
+    # Assert
+    assert result is None
+    assert repr(other_s3error) in caplog.text
+
+
+def test_should_log_error_when_getting_with_general_exception(
+    caplog: pytest.LogCaptureFixture,
+) -> None:
+    """Test that the MinioAdapter logs an error when getting a nonexistent object."""
+    # Arrange
+    adapter = MinioAdapter()
+    adapter._client = MagicMock(spec=Minio)
+    general_exception = Exception("General failure")
+    adapter._client.get_object.side_effect = general_exception
+    adapter._bucket_name = "test-bucket"
+    object_name = "missing-object"
+    # Act
+    with caplog.at_level("ERROR"):
+        result = adapter._get(object_name)
+    # Assert
+    assert result is None
+    assert repr(general_exception) in caplog.text
+
+
+def test_should_put_data(
+    data: BytesIO,
+    minio_adapter: MinioAdapter,
+) -> None:
+    """Test that the MinioAdapter can put data into a bucket."""
+    # Arrange
+    object_name = "new_test_object"
+    received_data = minio_adapter._get(object_name)  # type: ignore
+    assert received_data is None  # ensure object does not exist yet
+    # Act
+    minio_adapter._put(object_name, data)  # type: ignore
+    # Assert
+    received_data = minio_adapter._get(object_name)  # type: ignore
+    assert received_data is not None
+    assert same_data(data, received_data)
+    # Cleanup
+    bucket_name = str(os.getenv("MINIO_BUCKET"))
+    minio_adapter._client.remove_object(bucket_name, object_name)
+
+
+def test_should_update_data(
+    data_in_minio: tuple[str, BytesIO],
+    minio_adapter: MinioAdapter,
+) -> None:
+    """Test that the MinioAdapter can update data in a bucket."""
+    # Arrange
+    object_name, _ = data_in_minio
+    new_data = BytesIO(random.randbytes(2**21))  # 2 MiB
+    received_data = minio_adapter._get(object_name)  # type: ignore
+    assert received_data is not None
+    assert not same_data(received_data, new_data)
+    # Act
+    minio_adapter._put(object_name, new_data)  # type: ignore
+    # Assert
+    received_data = minio_adapter._get(object_name)  # type: ignore
+    assert received_data is not None
+    assert same_data(new_data, received_data)
+
+
+def test_should_raise_value_error_on_invalid_put_object_name(
+    data: BytesIO,
+    minio_adapter: MinioAdapter,
+) -> None:
+    """Test that the MinioAdapter raises ValueError when putting with an invalid object name."""
+    # Arrange
+    invalid_object_names = ["", 123, None]
+    # Act & Assert
+    for object_name in invalid_object_names:
+        with pytest.raises(ValueError):
+            minio_adapter._put(object_name, data)  # type: ignore
+
+
+def test_should_raise_value_error_on_invalid_put_data(
+    minio_adapter: MinioAdapter,
+) -> None:
+    """Test that the MinioAdapter raises ValueError when putting with invalid data."""
+    # Arrange
+    object_name = "valid_object_name"
+    invalid_data = ["not_bytesio", 123, None]
+    # Act & Assert
+    for data in invalid_data:
+        with pytest.raises(ValueError):
+            minio_adapter._put(object_name, data)  # type: ignore
+
+
+def test_should_raise_connection_error_on_put_when_not_connected(
+    data: BytesIO,
+    minio_adapter: MinioAdapter,
+) -> None:
+    """Test that the MinioAdapter raises ConnectionError when putting while not connected."""
+    # Arrange
+    adapter = MinioAdapter()  # not connected
+    # Act & Assert
+    with pytest.raises(ConnectionError):
+        adapter._put("some_object", data)  # type: ignore
+
+
+def test_should_delete_object(
+    data_in_minio: tuple[str, BytesIO],
+    minio_adapter: MinioAdapter,
+) -> None:
+    """Test that the MinioAdapter can delete an object from a bucket."""
+    # Arrange
+    object_name, _ = data_in_minio
+    received_data = minio_adapter._get(object_name)  # type: ignore
+    assert received_data is not None  # ensure object exists
+    # Act
+    minio_adapter._delete(object_name)  # type: ignore
+    # Assert
+    received_data = minio_adapter._get(object_name)  # type: ignore
+    assert received_data is None
+
+
+def test_should_raise_value_error_on_invalid_delete_object_name(
+    minio_adapter: MinioAdapter,
+) -> None:
+    """Test that the MinioAdapter raises ValueError when deleting with an invalid object name."""
+    # Arrange
+    invalid_object_names = ["", 123, None]
+    # Act & Assert
+    for object_name in invalid_object_names:
+        with pytest.raises(ValueError):
+            minio_adapter._delete(object_name)  # type: ignore
+
+
+def test_should_raise_connection_error_on_delete_when_not_connected(
+    minio_adapter: MinioAdapter,
+) -> None:
+    """Test that the MinioAdapter raises ConnectionError when deleting while not connected."""
+    # Arrange
+    adapter = MinioAdapter()  # not connected
+    # Act & Assert
+    with pytest.raises(ConnectionError):
+        adapter._delete("some_object")  # type: ignore
+
+
+def test_should_list_objects(
+    data_in_minio: tuple[str, BytesIO],
+    minio_adapter: MinioAdapter,
+) -> None:
+    """Test that the MinioAdapter can list objects in a bucket."""
+    # Arrange
+    object_name, _ = data_in_minio
+    new_data = BytesIO(random.randbytes(2**21))  # 2 MiB
+    new_data_name = "another_test_object"
+    minio_adapter._put(new_data_name, new_data)  # type: ignore
+    # Act
+    objects = minio_adapter._list_objects()  # type: ignore
+    # Assert
+    assert isinstance(objects, list)
+    assert len(objects) == 2
+    assert object_name in objects
+    assert new_data_name in objects
+
+
+def test_should_list_objects_with_prefix(
+    data_in_minio: tuple[str, BytesIO],
+    minio_adapter: MinioAdapter,
+) -> None:
+    """Test that the MinioAdapter can list objects in a bucket with a prefix."""
+    # Arrange
+    object_name, _ = data_in_minio
+    new_data = BytesIO(random.randbytes(2**21))  # 2 MiB
+    new_data_name = "prefix_test_object"
+    minio_adapter._put(new_data_name, new_data)  # type: ignore
+    prefix = "prefix_"
+    # Act
+    objects = minio_adapter._list_objects(prefix)  # type: ignore
+    # Assert
+    assert isinstance(objects, list)
+    assert len(objects) == 1
+    assert new_data_name in objects
+    assert object_name not in objects
+
+
+def test_should_raise_value_error_on_invalid_list_objects_prefix(
+    minio_adapter: MinioAdapter,
+) -> None:
+    """Test that the MinioAdapter raises ValueError when listing with an invalid prefix."""
+    # Arrange
+    invalid_prefixes = [123, None]
+    # Act & Assert
+    for prefix in invalid_prefixes:
+        with pytest.raises(ValueError):
+            minio_adapter._list_objects(prefix)  # type: ignore
+
+
+def test_should_raise_connection_error_on_list_objects_when_not_connected(
+    minio_adapter: MinioAdapter,
+) -> None:
+    """Test that the MinioAdapter raises ConnectionError when listing while not connected."""
+    # Arrange
+    adapter = MinioAdapter()  # not connected
+    # Act & Assert
+    with pytest.raises(ConnectionError):
+        adapter._list_objects()  # type: ignore
+
+
+# allows local debugging by running file as script
+if __name__ == "__main__":
+    pytest.main(["-s", "-v", __file__])