Test: Add tests for Bucket class

Author: ByteOtter

tests/s3/__init__.py

@@ -0,0 +1,146 @@
+"""
+Test the `Bucket` class in `src/gardenlinux/s3/bucket.py` by using
+mock AWS interactions provided by the `moto` module.
+
+The `@mock_aws` decorator `moto` provides ensures a fresh
+but fake AWS-like environment.
+"""
+
+import io
+import pytest
+import boto3
+from moto import mock_aws
+from pathlib import Path
+
+from gardenlinux.s3.bucket import Bucket
+
+
+BUCKET_NAME = "test-bucket"
+REGION = "us-east-1"
+
+
+
+@mock_aws
+def test_objects_empty():
+    """
+    List objects from empty bucket.
+    """
+    # Arrange
+    s3 = boto3.resource("s3", region_name=REGION)
+    s3.create_bucket(Bucket=BUCKET_NAME)
+
+    # Act
+    bucket = Bucket(bucket_name=BUCKET_NAME, s3_resource_config={"region_name": REGION})
+    objects = list(bucket.objects)
+
+    # Assert
+    assert objects == []
+
+
+@mock_aws
+def test_upload_file_and_list(tmp_path):
+    """
+    Create a fake file in a temporary directory, upload and try
+    to list it
+    """
+    # Arrange
+    s3 = boto3.resource("s3", region_name=REGION)
+    s3.create_bucket(Bucket=BUCKET_NAME)
+
+    test_file = tmp_path / "example.txt"
+    test_file.write_text("hello moto")
+
+    # Act
+    bucket = Bucket(bucket_name=BUCKET_NAME, s3_resource_config={"region_name": REGION})
+    bucket.upload_file(str(test_file), "example.txt")
+
+    all_keys = [obj.key for obj in bucket.objects]
+
+    # Assert
+    assert "example.txt" in all_keys
+
+
+@mock_aws
+def test_download_file(tmp_path):
+    """
+    Try to download a file pre-existing in the bucket
+    """
+    # Arrange
+    s3 = boto3.resource("s3", region_name=REGION)
+    s3.create_bucket(Bucket=BUCKET_NAME)
+    s3.Object(BUCKET_NAME, "file.txt").put(Body=b"some data")
+
+    # Act
+    bucket = Bucket(bucket_name=BUCKET_NAME, s3_resource_config={"region_name": REGION})
+
+    target_path = tmp_path / "downloaded.txt"
+    bucket.download_file("file.txt", str(target_path))
+
+    # Assert
+    assert target_path.read_text() == "some data"
+
+
+@mock_aws
+def test_upload_fileobj():
+    """
+    Upload a file-like in-memory object to the bucket
+    """
+    # Arrange
+    s3 = boto3.resource("s3", region_name=REGION)
+    s3.create_bucket(Bucket=BUCKET_NAME)
+
+    # Act
+    # Create in-memory binary stream (file content)
+    data = io.BytesIO(b"Test Data")
+    bucket = Bucket(bucket_name=BUCKET_NAME, s3_resource_config={"region_name": REGION})
+    bucket.upload_fileobj(data, "binary.obj")
+
+    obj = s3.Object(BUCKET_NAME, "binary.obj").get()
+
+    # Assert
+    assert obj["Body"].read() == b"Test Data"
+
+
+@mock_aws
+def test_download_fileobj():
+    """
+    Download data into a in-memory object
+    """
+    # Arange
+    s3 = boto3.resource("s3", region_name=REGION)
+    s3.create_bucket(Bucket=BUCKET_NAME)
+    # Put some object in the bucket
+    s3.Object(BUCKET_NAME, "somekey").put(Body=b"123abc")
+
+    # Act
+    bucket = Bucket(bucket_name=BUCKET_NAME, s3_resource_config={"region_name": REGION})
+
+    # Create empty in-memory bytestream to act as a writable file
+    output = io.BytesIO()
+    bucket.download_fileobj("somekey", output)
+
+    # Reset binary cursor to prepare for read
+    output.seek(0)
+
+    # Assert
+    assert output.read() == b"123abc"
+
+
+@mock_aws
+def test_getattr_delegates():
+    """
+    Verify that attribute access is delegated to the underlying boto3 Bucket.
+
+    This checks that accessing e.g. `.name` on our custom Bucket works by forwarding
+    the call to the real boto3 bucket.
+    """
+    # Arrange
+    s3 = boto3.resource("s3", region_name=REGION)
+    s3.create_bucket(Bucket=BUCKET_NAME)
+
+    # Act
+    bucket = Bucket(bucket_name=BUCKET_NAME, s3_resource_config={"region_name": REGION})
+
+    # Assert
+    # __getattr__ should delegate this to the underlying boto3 Bucket object
+    assert bucket.name == BUCKET_NAME