Fix tineye engine url, datetime parsing, and minor refactor

Changes made to tineye engine:
1. Importing logging if TYPE_CHECKING is enabled
2. Remove unecessary try-catch around json parsing the response, as this
masked the original error and had no immediate benefit
3. Improve error handling explicitely for status code 422 and 400
upfront, deferring json_parsing only for these status codes and
successful status codes
4. Unit test all new applicable changes to ensure compatability

tests/unit/test_tineye.py

@@ -0,0 +1,102 @@
+# SPDX-License-Identifier: AGPL-3.0-or-later
+# pylint: disable=missing-module-docstring
+
+
+from datetime import datetime
+from unittest.mock import Mock
+from requests import HTTPError
+from searx.engines import load_engines, tineye
+from tests import SearxTestCase
+
+
+class TinEyeTests(SearxTestCase):  # pylint: disable=missing-class-docstring
+
+    def setUp(self):
+        load_engines([{'name': 'tineye', 'engine': 'tineye', 'shortcut': 'tin', 'timeout': 9.0, 'disabled': True}])
+
+    def tearDown(self):
+        load_engines([])
+
+    def test_status_code_raises(self):
+        response = Mock()
+        response.status_code = 401
+        response.raise_for_status.side_effect = HTTPError()
+        self.assertRaises(HTTPError, lambda: tineye.response(response))
+
+    def test_returns_empty_list_for_422(self):
+        response = Mock()
+        response.json.return_value = {}
+        response.status_code = 422
+        response.raise_for_status.side_effect = HTTPError()
+        with self.assertLogs(tineye.logger) as _dev_null:
+            results = tineye.response(response)
+        self.assertEqual(0, len(results))
+
+    def test_logs_format_for_422(self):
+        response = Mock()
+        response.json.return_value = {"suggestions": {"key": "Invalid image URL"}}
+        response.status_code = 422
+        response.raise_for_status.side_effect = HTTPError()
+
+        with self.assertLogs(tineye.logger) as assert_logs_context:
+            tineye.response(response)
+            self.assertIn(tineye.FORMAT_NOT_SUPPORTED, ','.join(assert_logs_context.output))
+
+    def test_logs_signature_for_422(self):
+        response = Mock()
+        response.json.return_value = {"suggestions": {"key": "NO_SIGNATURE_ERROR"}}
+        response.status_code = 422
+        response.raise_for_status.side_effect = HTTPError()
+
+        with self.assertLogs(tineye.logger) as assert_logs_context:
+            tineye.response(response)
+            self.assertIn(tineye.NO_SIGNATURE_ERROR, ','.join(assert_logs_context.output))
+
+    def test_logs_download_for_422(self):
+        response = Mock()
+        response.json.return_value = {"suggestions": {"key": "Download Error"}}
+        response.status_code = 422
+        response.raise_for_status.side_effect = HTTPError()
+
+        with self.assertLogs(tineye.logger) as assert_logs_context:
+            tineye.response(response)
+            self.assertIn(tineye.DOWNLOAD_ERROR, ','.join(assert_logs_context.output))
+
+    def test_empty_list_for_400(self):
+        response = Mock()
+        response.json.return_value = {}
+        response.status_code = 400
+        response.raise_for_status.side_effect = HTTPError()
+        with self.assertLogs(tineye.logger) as _dev_null:
+            results = tineye.response(response)
+        self.assertEqual(0, len(results))
+
+    def test_logs_description_for_400(self):
+        description = 'There was a problem with that request. Error ID: ad5fc955-a934-43c1-8187-f9a61d301645'
+        response = Mock()
+        response.json.return_value = {"suggestions": {"description": [description], "title": "Oops! We're sorry!"}}
+        response.status_code = 400
+        response.raise_for_status.side_effect = HTTPError()
+
+        with self.assertLogs(tineye.logger) as assert_logs_context:
+            tineye.response(response)
+            self.assertIn(description, ','.join(assert_logs_context.output))
+
+    def test_crawl_date_parses(self):
+        date_str = '2020-05-25'
+        date = datetime.strptime(date_str, '%Y-%m-%d')
+        response = Mock()
+        response.json.return_value = {
+            'matches': [
+                {
+                    'backlinks': [
+                        {
+                            'crawl_date': date_str,
+                        }
+                    ]
+                }
+            ]
+        }
+        response.status_code = 200
+        results = tineye.response(response)
+        self.assertEqual(date, results[0]['publishedDate'])