Add test test_pngquant

Author: NicolasSandoval

tests/test_pngquant.py

@@ -0,0 +1,38 @@
+# Copyright 2021 CDPedistas (see AUTHORS.txt)
+#
+# This program is free software: you can redistribute it and/or modify it
+# under the terms of the GNU General Public License version 3, as published
+# by the Free Software Foundation.
+#
+# This program is distributed in the hope that it will be useful, but
+# WITHOUT ANY WARRANTY; without even the implied warranties of
+# MERCHANTABILITY, SATISFACTORY QUALITY, or FITNESS FOR A PARTICULAR
+# PURPOSE.  See the GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License along
+# with this program.  If not, see <http://www.gnu.org/licenses/>.
+#
+# For further info, check  https://github.com/PyAr/CDPedia/
+
+import os
+import shutil
+
+from src.images.download import optimize_png
+
+import pytest
+
+
+@pytest.fixture
+def image_config(tmp_path):
+    img_test_name = 'tests/fixtures/image_to_optimize.png'
+    test_path = str(tmp_path / 'image_to_optimize.png')
+    shutil.copy(img_test_name, test_path)
+    init_size = os.stat(img_test_name).st_size
+    return test_path, init_size
+
+
+def test_optimize(image_config):
+    img_path, init_size = image_config
+    optimize_png(img_path, init_size, init_size)
+    final_size = os.stat(img_path).st_size
+    assert init_size > final_size