test: add decrypt files tests

tests/decryption/test_decrypt.py

@@ -1,11 +1,14 @@
 """Tests for decrypt.py"""
 from pathlib import Path
+import shutil
+
+from crypt4gh.keys import get_private_key as get_sk_bytes, get_public_key as get_pk_bytes
 import pytest
 
-from crypt4gh.keys import get_private_key as get_pk_bytes
-from decrypt import get_private_keys
+from crypt4gh_middleware.decrypt import get_private_keys, decrypt_files
 
 INPUT_DIR = Path(__file__).parents[2]/"inputs"
+INPUT_TEXT = "hello world from the input!"
 
 
 class TestGetPrivateKeys:
@@ -31,7 +34,66 @@ def test_get_keys(self, files, expected_keys_retrieved):
         Ensure that `get_private_keys` gets only private keys from a list of files.
         """
         def get_expected_bytes():
-            return [get_pk_bytes(INPUT_DIR/filename, callback=lambda x: '')
+            return [get_sk_bytes(INPUT_DIR/filename, callback=lambda x: '')
                     for filename in expected_keys_retrieved]
 
         assert get_private_keys([INPUT_DIR/file for file in files]) == get_expected_bytes()
+
+
+class TestDecryptFiles:
+    """Test decrypt_files."""
+
+    @pytest.fixture()
+    def key_pair(self):
+        """Returns the key pair used to encrypt the input files."""
+        return INPUT_DIR/"alice.sec", INPUT_DIR/"alice.pub"
+
+    @pytest.fixture()
+    def key_pair_bytes(self, key_pair):
+        """Returns the bytes of the key pair."""
+        sk, pk = key_pair
+        sk_bytes = get_sk_bytes(filepath=sk, callback=lambda x: '')
+        pk_bytes = get_pk_bytes(filepath=pk)
+        return sk_bytes, pk_bytes
+
+    @pytest.fixture()
+    def encrypted_files(self, tmp_path):
+        """Returns temporary copies of encrypted files."""
+        encrypted_files = [INPUT_DIR/"hello.c4gh", INPUT_DIR/"hello2.c4gh"]
+        temp_files = [tmp_path/"hello.c4gh", tmp_path/"hello2.c4gh"]
+        for src, dest in zip(encrypted_files, temp_files):
+            shutil.copy(src, dest)
+        return temp_files
+
+    @pytest.fixture()
+    def unencrypted_files(self):
+        """Returns the unencrypted file paths"""
+        return [INPUT_DIR/"hello.txt"]
+
+    @pytest.mark.parametrize("files", ["encrypted_files", "unencrypted_files", []])
+    def test_handles_encrypted_and_unencrypted_files(self, files, key_pair_bytes, request):
+        """Test that decrypt_files decrypts only encrypted files in-place.
+
+        Ensure no exception is thrown when attempting to decrypt unencrypted files.
+        """
+        def files_exist():
+            return all(file_path.exists() for file_path in files)
+
+        def file_contents_are_valid():
+            for file_path in files:
+                with open(file_path, encoding="utf-8") as f:
+                    output = f.read()
+                    if output != INPUT_TEXT:
+                        return False
+            return True
+
+        # Fixture names passed to pytest.mark.parametrize are strings, so get value
+        if isinstance(files, str):
+            files = request.getfixturevalue(files)
+
+        assert files_exist()
+        decrypt_files(file_paths=files,
+                      private_keys=[key_pair_bytes[0]])
+        assert files_exist()
+
+        assert file_contents_are_valid()