Add additional multi-layer complex squashing test

test/registry/registry_tests.py

@@ -930,6 +930,58 @@ def test_squashed_image_disabled_user(pusher, sized_images, liveserver_session,
   assert response.status_code == 403
 
 
+@pytest.mark.parametrize('use_estimates', [
+  False,
+  True,
+])
+def test_multilayer_squashed_images(use_estimates, pusher, multi_layer_images, liveserver_session,
+                                    liveserver, registry_server_executor, app_reloader):
+  """ Test: Pulling of multilayer, complex squashed images. """
+  credentials = ('devtable', 'password')
+
+  # Push an image to download.
+  pusher.push(liveserver_session, 'devtable', 'newrepo', 'latest', multi_layer_images,
+              credentials=credentials)
+
+  if use_estimates:
+    # Clear the uncompressed size stored for the images, to ensure that we estimate instead.
+    for image in multi_layer_images:
+      registry_server_executor.on(liveserver).clear_uncompressed_size(image.id)
+
+  # Pull the squashed version.
+  response = liveserver_session.get('/c1/squash/devtable/newrepo/latest', auth=credentials)
+  tar = tarfile.open(fileobj=StringIO(response.content))
+
+  # Verify the squashed image.
+  expected_image_id = 'cdc6d6c0d07d2cbacfc579e49ce0c256c5084b9b2b16c1b1b0c45f26a12a4ba5'
+  expected_names = ['repositories',
+                    expected_image_id,
+                    '%s/json' % expected_image_id,
+                    '%s/VERSION' % expected_image_id,
+                    '%s/layer.tar' % expected_image_id]
+
+  assert tar.getnames() == expected_names
+
+  # Verify the JSON image data.
+  json_data = (tar.extractfile(tar.getmember('%s/json' % expected_image_id)).read())
+
+  # Ensure the JSON loads and parses.
+  result = json.loads(json_data)
+  assert result['id'] == expected_image_id
+  assert result['config']['internal_id'] == 'layer5'
+
+  # Ensure that squashed layer tar can be opened.
+  tar = tarfile.open(fileobj=tar.extractfile(tar.getmember('%s/layer.tar' % expected_image_id)))
+  assert set(tar.getnames()) == {'contents', 'file1', 'file2', 'file3', 'file4'}
+
+  # Check the contents of various files.
+  assert tar.extractfile('contents').read() == 'layer 5 contents'
+  assert tar.extractfile('file1').read() == 'from-layer-3'
+  assert tar.extractfile('file2').read() == 'from-layer-2'
+  assert tar.extractfile('file3').read() == 'from-layer-4'
+  assert tar.extractfile('file4').read() == 'from-layer-5'
+
+
 @pytest.mark.parametrize('use_estimates', [
   False,
   True,