Include test cases for handling zero-size files in rohmu.

test/test_rohmu.py

@@ -0,0 +1,163 @@
+import hashlib
+import logging
+import os
+from tempfile import NamedTemporaryFile
+
+import pytest
+from rohmu import get_transfer, rohmufile
+from rohmu.rohmufile import create_sink_pipeline
+
+from .base import CONSTANT_TEST_RSA_PRIVATE_KEY, CONSTANT_TEST_RSA_PUBLIC_KEY
+
+log = logging.getLogger(__name__)
+
+
+@pytest.mark.parametrize(
+    "compress_algorithm, file_size",
+    [("lzma", 0), ("snappy", 0), ("zstd", 0), ("lzma", 1), ("snappy", 1), ("zstd", 1)],
+    ids=[
+        "test_lzma_0byte_file", "test_snappy_0byte_file", "test_zstd_0byte_file", "test_lzma_1byte_file",
+        "test_snappy_1byte_file", "test_zstd_1byte_file"
+    ],
+)
+def test_rohmu_with_local_storage(compress_algorithm: str, file_size: int, tmp_path):
+    hash_algorithm = "sha1"
+    compression_level = 0
+
+    # 0 - Prepare the file
+    work_dir = tmp_path
+    orig_file = work_dir / "hello.bin"
+    content = os.urandom(file_size)
+    with open(orig_file, "wb") as file_out:
+        file_out.write(content)
+
+    with open(orig_file, "rb") as file_in:
+        assert file_in.read() == content
+
+    # 1 - Compressed the file
+    compressed_filepath = work_dir / "compressed" / "hello_compressed"
+    compressed_filepath.parent.mkdir(exist_ok=True)
+    hasher = hashlib.new(hash_algorithm)
+    input_obj = open(orig_file, "rb")
+    output_obj = NamedTemporaryFile(
+        dir=os.path.dirname(compressed_filepath), prefix=os.path.basename(compressed_filepath), suffix=".tmp-compress"
+    )
+    with input_obj, output_obj:
+        original_file_size, compressed_file_size = rohmufile.write_file(
+            data_callback=hasher.update,
+            input_obj=input_obj,
+            output_obj=output_obj,
+            compression_algorithm=compress_algorithm,
+            compression_level=compression_level,
+            rsa_public_key=CONSTANT_TEST_RSA_PUBLIC_KEY,
+            log_func=log.debug,
+        )
+        os.link(output_obj.name, compressed_filepath)
+
+    log.info("original_file_size: %s, compressed_file_size: %s", original_file_size, compressed_file_size)
+    assert original_file_size == len(content)
+    file_hash = hasher.hexdigest()
+    log.info("original_file_hash: %s", file_hash)
+
+    # 2 - Upload the compressed file
+    upload_dir = work_dir / "uploaded"
+    upload_dir.mkdir()
+    storage_config = {
+        "directory": str(upload_dir),
+        "storage_type": "local",
+    }
+    metadata = {
+        "encryption-key-id": "No matter",
+        "compression-algorithm": compress_algorithm,
+        "compression-level": compression_level,
+    }
+    storage = get_transfer(storage_config)
+
+    metadata_copy = metadata.copy()
+    metadata_copy["Content-Length"] = str(compressed_file_size)
+    file_key = "compressed/hello_compressed"
+
+    def upload_progress_callback(n_bytes: int) -> None:
+        log.debug("File: '%s', uploaded %d bytes", file_key, n_bytes)
+
+    with open(compressed_filepath, "rb") as f:
+        storage.store_file_object(file_key, f, metadata=metadata_copy, upload_progress_fn=upload_progress_callback)
+
+    # 3 - Decrypt and decompress
+    # 3.1 Use file downloading rohmu API
+    decompressed_filepath = work_dir / "hello_decompressed_1"
+
+    decompressed_size = _download_and_decompress_with_file(storage, str(decompressed_filepath), file_key, metadata)
+    assert len(content) == decompressed_size
+    # Compare content
+    with open(decompressed_filepath, "rb") as file_in:
+        content_decrypted = file_in.read()
+        hasher = hashlib.new(hash_algorithm)
+        hasher.update(content_decrypted)
+        assert hasher.hexdigest() == file_hash
+        assert content_decrypted == content
+
+    # 3.2 Use rohmu SinkIO API
+    decompressed_filepath = work_dir / "hello_decompressed_2"
+    decompressed_size = _download_and_decompress_with_sink(storage, str(decompressed_filepath), file_key, metadata)
+    assert len(content) == decompressed_size
+
+    # Compare content
+    hasher.hexdigest()
+    with open(decompressed_filepath, "rb") as file_in:
+        content_decrypted = file_in.read()
+        hasher = hashlib.new(hash_algorithm)
+        hasher.update(content_decrypted)
+        assert hasher.hexdigest() == file_hash
+        assert content_decrypted == content
+
+    if file_size == 0:
+        empty_file_sha1 = "da39a3ee5e6b4b0d3255bfef95601890afd80709"
+        assert empty_file_sha1 == hasher.hexdigest()
+
+
+def _key_lookup(key_id: str):  # pylint: disable=unused-argument
+    return CONSTANT_TEST_RSA_PRIVATE_KEY
+
+
+def _download_and_decompress_with_sink(storage, output_path: str, file_key: str, metadata: dict):
+    data, _ = storage.get_contents_to_string(file_key)
+    if isinstance(data, str):
+        data = data.encode("latin1")
+    file_size = len(data)
+
+    with open(output_path, "wb") as target_file:
+        output = create_sink_pipeline(
+            output=target_file, file_size=file_size, metadata=metadata, key_lookup=_key_lookup, throttle_time=0
+        )
+        output.write(data)
+    decompressed_size = os.path.getsize(output_path)
+    return decompressed_size
+
+
+def _download_and_decompress_with_file(storage, output_path: str, file_key: str, metadata: dict):
+    # Download the compressed file
+    file_download_path = output_path + ".tmp"
+
+    def download_progress_callback(bytes_written: int, input_size: int) -> None:
+        log.debug("File: '%s', downloaded %d of %d bytes", file_key, bytes_written, input_size)
+
+    with open(file_download_path, "wb") as f:
+        storage.get_contents_to_fileobj(file_key, f, progress_callback=download_progress_callback)
+
+    # Decrypt and decompress
+    input_obj = open(file_download_path, "rb")
+    output_obj = open(output_path, "wb")
+    with input_obj, output_obj:
+        _, decompressed_size = rohmufile.read_file(
+            input_obj=input_obj,
+            output_obj=output_obj,
+            metadata=metadata,
+            key_lookup=_key_lookup,
+            log_func=log.debug,
+        )
+        output_obj.flush()
+
+    # Delete temporary file
+    os.unlink(file_download_path)
+    return decompressed_size