test_translate_function_3.py

class TranslateFileTest(unittest.TestCase):

    # Test for valid file type (.txt)
    @mock.patch('translate_file.app.read_file', side_effect=mocked_read_file)
    @mock.patch('translate_file.app.translate_text', side_effect=mocked_translate_text)
    def test_valid_file(self, translate_text_mock, read_file_mock):

        response = lambda_handler(self.s3_upload_event("valid_file.txt"), "")
        expected_response = {
            "success": True,
            "original_text":"我爱写单元测试！",
            "translated_text":"I love writing unit tests!",
            "original_language":"zh",
            "target_language":"en"
        }

        self.assertEqual(read_file_mock.call_count, 1)
        self.assertEqual(translate_text_mock.call_count, 1)
        self.assertEqual(response, expected_response)
    
    # Test for invalid file type (.pdf)
    @mock.patch('translate_file.app.read_file', side_effect=mocked_read_file)
    @mock.patch('translate_file.app.translate_text', side_effect=mocked_translate_text)
    def test_invalid_file(self, translate_text_mock, read_file_mock):

        response = lambda_handler(self.s3_upload_event("invalid_file.pdf"), "")
        expected_response = {
            "success": False,
            "response": "Invalid file type. File must have .txt extension."
        }

        self.assertEqual(read_file_mock.call_count, 0)
        self.assertEqual(translate_text_mock.call_count, 0)
        self.assertEqual(response, expected_response)