Test: Add unit test cases for downsample_and_save_image function in u…

…tils

tests/test_downsample.py

@@ -0,0 +1,141 @@
+import unittest
+from unittest import mock
+from unittest.mock import patch, MagicMock
+import os
+from PIL import Image
+from cautiousrobot.utils import log_response, update_log, process_csv, downsample_and_save_image
+
+class TestDownsampleAndSaveImage(unittest.TestCase):
+    """Test the downsample_and_save_image function."""
+
+    def setUp(self):
+        self.image_dir_path = "test_images"
+        self.downsample_dir_path = "downsampled_images"
+        self.downsample_size = 100
+        self.log_errors = {} # Dictionary to store error logs
+        self.error_log_filepath = "error_log.json"
+        self.url = "http://example.com/image.jpg"
+
+    def tearDown(self):
+        if os.path.exists(self.image_dir_path):
+            os.rmdir(self.image_dir_path)
+        if os.path.exists(self.downsample_dir_path):
+            os.rmdir(self.downsample_dir_path)
+        if os.path.exists(self.error_log_filepath):
+            os.remove(self.error_log_filepath)
+
+    def mock_log_response_side_effect(self, log_errors, index, image, url, response_code):
+        """Helper function to mimic the behavior of log_response."""
+        log_errors[index] = {'image': image, 'url': url, 'response_code': response_code}
+        return log_errors
+
+    @patch("os.makedirs")
+    @patch("os.path.exists", return_value=False)
+    @patch("PIL.Image.open")
+    def test_downsample_and_save_image_success(self, mock_open, mock_exists, mock_makedirs):
+        """ Test the successful downsampling and saving of an image. """ 
+
+        mock_image = MagicMock(spec=Image.Image)
+        mock_open.return_value = mock_image
+
+        # The image is resized to a new image
+        mock_resized_image = MagicMock(spec=Image.Image)
+        mock_image.resize.return_value = mock_resized_image
+
+        downsample_and_save_image(
+            self.image_dir_path,
+            "test_image.jpg",
+            self.downsample_dir_path,
+            self.downsample_size,
+            self.log_errors,
+            0,  # image_index
+            self.url,
+            self.error_log_filepath
+        )
+
+        mock_makedirs.assert_called_once_with(self.downsample_dir_path, exist_ok=False)
+        mock_open.assert_called_once_with(f"{self.image_dir_path}/test_image.jpg")
+        mock_image.resize.assert_called_once_with((self.downsample_size, self.downsample_size))
+        mock_resized_image.save.assert_called_once_with(f"{self.downsample_dir_path}/test_image.jpg")
+
+    @patch("os.makedirs")
+    @patch("os.path.exists", return_value=True)
+    @patch("PIL.Image.open", side_effect=FileNotFoundError("File not found"))
+    @patch("cautiousrobot.utils.log_response")
+    @patch("cautiousrobot.utils.update_log")
+    def test_downsample_and_save_image_file_not_found(self, mock_update_log, mock_log_response, mock_open, mock_exists, mock_makedirs):
+        """ Test the behavior when the image file is not found. """
+
+        mock_log_response.side_effect = self.mock_log_response_side_effect
+
+        downsample_and_save_image(
+            self.image_dir_path,
+            "missing_image.jpg",
+            self.downsample_dir_path,
+            self.downsample_size,
+            self.log_errors,
+            0,  # image_index
+            self.url,
+            self.error_log_filepath
+        )
+
+        mock_makedirs.assert_not_called()
+        mock_open.assert_called_once_with(f"{self.image_dir_path}/missing_image.jpg")
+        mock_log_response.assert_called_once_with(
+            self.log_errors,
+            index=0,
+            image="downsized_missing_image.jpg",
+            url=self.url,
+            response_code="File not found"
+        )
+        mock_update_log.assert_called_once_with(
+            log=self.log_errors,
+            index=0,
+            filepath=self.error_log_filepath
+        )
+
+        # Check the log error dictionary
+        self.assertIn(0, self.log_errors)
+        self.assertEqual(self.log_errors[0]['response_code'], "File not found")
+
+    @patch("os.makedirs")
+    @patch("os.path.exists", return_value=False)
+    @patch("PIL.Image.open", side_effect=Exception("Unexpected error"))
+    @patch("cautiousrobot.utils.log_response")
+    @patch("cautiousrobot.utils.update_log")
+    def test_downsample_and_save_image_unexpected_error(self, mock_update_log, mock_log_response, mock_open, mock_exists, mock_makedirs):
+        """ Test the behavior when an unexpected error occurs. """
+
+        mock_log_response.side_effect = self.mock_log_response_side_effect
+
+        downsample_and_save_image(
+            self.image_dir_path,
+            "test_image.jpg",
+            self.downsample_dir_path,
+            self.downsample_size,
+            self.log_errors,
+            1, 
+            self.url,
+            self.error_log_filepath
+        )
+
+        mock_makedirs.assert_called_once_with(self.downsample_dir_path, exist_ok=False)
+        mock_open.assert_called_once_with(f"{self.image_dir_path}/test_image.jpg")
+        mock_log_response.assert_called_once_with(
+            self.log_errors,
+            index=1,
+            image="downsized_test_image.jpg",
+            url=self.url,
+            response_code="Unexpected error"
+        )
+        mock_update_log.assert_called_once_with(
+            log=self.log_errors,
+            index=1,
+            filepath=self.error_log_filepath
+        )
+
+        self.assertIn(1, self.log_errors)
+        self.assertEqual(self.log_errors[1]['response_code'], "Unexpected error")
+
+if __name__ == "__main__":
+    unittest.main()