diff --git a/searx/query.py b/searx/query.py
index ae68d0da2..aa4cb0bc9 100644
--- a/searx/query.py
+++ b/searx/query.py
@@ -1,6 +1,7 @@
 # SPDX-License-Identifier: AGPL-3.0-or-later
 # pylint: disable=invalid-name, missing-module-docstring, missing-class-docstring
 
+from __future__ import annotations
 from abc import abstractmethod, ABC
 import re
 
@@ -258,7 +259,7 @@ class RawTextQuery:
         FeelingLuckyParser,  # redirect to the first link in the results list
     ]
 
-    def __init__(self, query, disabled_engines):
+    def __init__(self, query: str, disabled_engines: list):
         assert isinstance(query, str)
         # input parameters
         self.query = query
diff --git a/tests/unit/test_answerers.py b/tests/unit/test_answerers.py
index e96e20c3c..716b544de 100644
--- a/tests/unit/test_answerers.py
+++ b/tests/unit/test_answerers.py
@@ -2,15 +2,16 @@
 # pylint: disable=missing-module-docstring
 
 from mock import Mock
+from parameterized import parameterized
 
 from searx.answerers import answerers
 from tests import SearxTestCase
 
 
 class AnswererTest(SearxTestCase):  # pylint: disable=missing-class-docstring
-    def test_unicode_input(self):
+    @parameterized.expand(answerers)
+    def test_unicode_input(self, answerer):
         query = Mock()
         unicode_payload = 'árvíztűrő tükörfúrógép'
-        for answerer in answerers:
-            query.query = '{} {}'.format(answerer.keywords[0], unicode_payload)
-            self.assertTrue(isinstance(answerer.answer(query), list))
+        query.query = '{} {}'.format(answerer.keywords[0], unicode_payload)
+        self.assertIsInstance(answerer.answer(query), list)
diff --git a/tests/unit/test_exceptions.py b/tests/unit/test_exceptions.py
index 514b9ce1f..fb2834058 100644
--- a/tests/unit/test_exceptions.py
+++ b/tests/unit/test_exceptions.py
@@ -1,42 +1,36 @@
 # SPDX-License-Identifier: AGPL-3.0-or-later
 # pylint: disable=missing-module-docstring
 
+from parameterized import parameterized
 from tests import SearxTestCase
 import searx.exceptions
 from searx import get_setting
 
 
 class TestExceptions(SearxTestCase):  # pylint: disable=missing-class-docstring
-    def test_default_suspend_time(self):
-        with self.assertRaises(searx.exceptions.SearxEngineAccessDeniedException) as e:
-            raise searx.exceptions.SearxEngineAccessDeniedException()
+    @parameterized.expand(
+        [
+            searx.exceptions.SearxEngineAccessDeniedException,
+            searx.exceptions.SearxEngineCaptchaException,
+            searx.exceptions.SearxEngineTooManyRequestsException,
+        ]
+    )
+    def test_default_suspend_time(self, exception):
+        with self.assertRaises(exception) as e:
+            raise exception()
         self.assertEqual(
             e.exception.suspended_time,
-            get_setting(searx.exceptions.SearxEngineAccessDeniedException.SUSPEND_TIME_SETTING),
+            get_setting(exception.SUSPEND_TIME_SETTING),
         )
 
-        with self.assertRaises(searx.exceptions.SearxEngineCaptchaException) as e:
-            raise searx.exceptions.SearxEngineCaptchaException()
-        self.assertEqual(
-            e.exception.suspended_time, get_setting(searx.exceptions.SearxEngineCaptchaException.SUSPEND_TIME_SETTING)
-        )
-
-        with self.assertRaises(searx.exceptions.SearxEngineTooManyRequestsException) as e:
-            raise searx.exceptions.SearxEngineTooManyRequestsException()
-        self.assertEqual(
-            e.exception.suspended_time,
-            get_setting(searx.exceptions.SearxEngineTooManyRequestsException.SUSPEND_TIME_SETTING),
-        )
-
-    def test_custom_suspend_time(self):
-        with self.assertRaises(searx.exceptions.SearxEngineAccessDeniedException) as e:
-            raise searx.exceptions.SearxEngineAccessDeniedException(suspended_time=1337)
+    @parameterized.expand(
+        [
+            searx.exceptions.SearxEngineAccessDeniedException,
+            searx.exceptions.SearxEngineCaptchaException,
+            searx.exceptions.SearxEngineTooManyRequestsException,
+        ]
+    )
+    def test_custom_suspend_time(self, exception):
+        with self.assertRaises(exception) as e:
+            raise exception(suspended_time=1337)
         self.assertEqual(e.exception.suspended_time, 1337)
-
-        with self.assertRaises(searx.exceptions.SearxEngineCaptchaException) as e:
-            raise searx.exceptions.SearxEngineCaptchaException(suspended_time=1409)
-        self.assertEqual(e.exception.suspended_time, 1409)
-
-        with self.assertRaises(searx.exceptions.SearxEngineTooManyRequestsException) as e:
-            raise searx.exceptions.SearxEngineTooManyRequestsException(suspended_time=1543)
-        self.assertEqual(e.exception.suspended_time, 1543)
diff --git a/tests/unit/test_external_bangs.py b/tests/unit/test_external_bangs.py
index ad20d52f7..153521599 100644
--- a/tests/unit/test_external_bangs.py
+++ b/tests/unit/test_external_bangs.py
@@ -90,7 +90,7 @@ class TestGetBangDefinitionAndAutocomplete(SearxTestCase):  # pylint:disable=mis
 
     def test_partial(self):
         bang_definition, new_autocomplete = get_bang_definition_and_autocomplete('examp', external_bangs_db=TEST_DB)
-        self.assertEqual(bang_definition, None)
+        self.assertIsNone(bang_definition)
         self.assertEqual(new_autocomplete, ['example'])
 
     def test_partial2(self):
@@ -100,7 +100,7 @@ class TestGetBangDefinitionAndAutocomplete(SearxTestCase):  # pylint:disable=mis
 
     def test_error(self):
         bang_definition, new_autocomplete = get_bang_definition_and_autocomplete('error', external_bangs_db=TEST_DB)
-        self.assertEqual(bang_definition, None)
+        self.assertIsNone(bang_definition)
         self.assertEqual(new_autocomplete, [])
 
     def test_actual_data(self):
@@ -112,7 +112,7 @@ class TestGetBangDefinitionAndAutocomplete(SearxTestCase):  # pylint:disable=mis
 class TestExternalBangJson(SearxTestCase):  # pylint:disable=missing-class-docstring
     def test_no_external_bang_query(self):
         result = get_bang_url(SearchQuery('test', engineref_list=[EngineRef('wikipedia', 'general')]))
-        self.assertEqual(result, None)
+        self.assertIsNone(result)
 
     def test_get_bang_url(self):
         url = get_bang_url(SearchQuery('test', engineref_list=[], external_bang='example'), external_bangs_db=TEST_DB)
diff --git a/tests/unit/test_locales.py b/tests/unit/test_locales.py
index 6407a5761..37cc187da 100644
--- a/tests/unit/test_locales.py
+++ b/tests/unit/test_locales.py
@@ -2,6 +2,8 @@
 # pylint: disable=missing-module-docstring
 """Test some code from module :py:obj:`searx.locales`"""
 
+from __future__ import annotations
+from parameterized import parameterized
 from searx import locales
 from searx.sxng_locales import sxng_locales
 from tests import SearxTestCase
@@ -13,98 +15,104 @@ class TestLocales(SearxTestCase):
     - :py:obj:`searx.locales.match_locale`
     """
 
-    def test_match_locale(self):
-
-        locale_tag_list = [x[0] for x in sxng_locales]
+    @classmethod
+    def setUpClass(cls):
+        cls.locale_tag_list = [x[0] for x in sxng_locales]
 
+    @parameterized.expand(
+        [
+            'de',
+            'fr',
+            'zh',
+        ]
+    )
+    def test_locale_languages(self, locale: str):
         # Test SearXNG search languages
+        self.assertEqual(locales.match_locale(locale, self.locale_tag_list), locale)
 
-        self.assertEqual(locales.match_locale('de', locale_tag_list), 'de')
-        self.assertEqual(locales.match_locale('fr', locale_tag_list), 'fr')
-        self.assertEqual(locales.match_locale('zh', locale_tag_list), 'zh')
-
+    @parameterized.expand(
+        [
+            ('ca-es', 'ca-ES'),
+            ('de-at', 'de-AT'),
+            ('de-de', 'de-DE'),
+            ('en-UK', 'en-GB'),
+            ('fr-be', 'fr-BE'),
+            ('fr-be', 'fr-BE'),
+            ('fr-ca', 'fr-CA'),
+            ('fr-ch', 'fr-CH'),
+            ('zh-cn', 'zh-CN'),
+            ('zh-tw', 'zh-TW'),
+            ('zh-hk', 'zh-HK'),
+        ]
+    )
+    def test_match_region(self, locale: str, expected_locale: str):
         # Test SearXNG search regions
+        self.assertEqual(locales.match_locale(locale, self.locale_tag_list), expected_locale)
 
-        self.assertEqual(locales.match_locale('ca-es', locale_tag_list), 'ca-ES')
-        self.assertEqual(locales.match_locale('de-at', locale_tag_list), 'de-AT')
-        self.assertEqual(locales.match_locale('de-de', locale_tag_list), 'de-DE')
-        self.assertEqual(locales.match_locale('en-UK', locale_tag_list), 'en-GB')
-        self.assertEqual(locales.match_locale('fr-be', locale_tag_list), 'fr-BE')
-        self.assertEqual(locales.match_locale('fr-be', locale_tag_list), 'fr-BE')
-        self.assertEqual(locales.match_locale('fr-ca', locale_tag_list), 'fr-CA')
-        self.assertEqual(locales.match_locale('fr-ch', locale_tag_list), 'fr-CH')
-        self.assertEqual(locales.match_locale('zh-cn', locale_tag_list), 'zh-CN')
-        self.assertEqual(locales.match_locale('zh-tw', locale_tag_list), 'zh-TW')
-        self.assertEqual(locales.match_locale('zh-hk', locale_tag_list), 'zh-HK')
-
+    @parameterized.expand(
+        [
+            ('zh-hans', 'zh-CN'),
+            ('zh-hans-cn', 'zh-CN'),
+            ('zh-hant', 'zh-TW'),
+            ('zh-hant-tw', 'zh-TW'),
+        ]
+    )
+    def test_match_lang_script_code(self, locale: str, expected_locale: str):
         # Test language script code
+        self.assertEqual(locales.match_locale(locale, self.locale_tag_list), expected_locale)
 
-        self.assertEqual(locales.match_locale('zh-hans', locale_tag_list), 'zh-CN')
-        self.assertEqual(locales.match_locale('zh-hans-cn', locale_tag_list), 'zh-CN')
-        self.assertEqual(locales.match_locale('zh-hant', locale_tag_list), 'zh-TW')
-        self.assertEqual(locales.match_locale('zh-hant-tw', locale_tag_list), 'zh-TW')
-
-        # Test individual locale lists
+    def test_locale_de(self):
+        self.assertEqual(locales.match_locale('de', ['de-CH', 'de-DE']), 'de-DE')
+        self.assertEqual(locales.match_locale('de', ['de-CH', 'de-DE']), 'de-DE')
 
+    def test_locale_es(self):
         self.assertEqual(locales.match_locale('es', [], fallback='fallback'), 'fallback')
-
-        self.assertEqual(locales.match_locale('de', ['de-CH', 'de-DE']), 'de-DE')
-        self.assertEqual(locales.match_locale('de', ['de-CH', 'de-DE']), 'de-DE')
         self.assertEqual(locales.match_locale('es', ['ES']), 'ES')
         self.assertEqual(locales.match_locale('es', ['es-AR', 'es-ES', 'es-MX']), 'es-ES')
         self.assertEqual(locales.match_locale('es-AR', ['es-AR', 'es-ES', 'es-MX']), 'es-AR')
         self.assertEqual(locales.match_locale('es-CO', ['es-AR', 'es-ES']), 'es-ES')
         self.assertEqual(locales.match_locale('es-CO', ['es-AR']), 'es-AR')
 
-        # Tests from the commit message of 9ae409a05a
+    @parameterized.expand(
+        [
+            ('zh-TW', ['zh-HK'], 'zh-HK'),  # A user selects region 'zh-TW' which should end in zh_HK.
+            # hint: CN is 'Hans' and HK ('Hant') fits better to TW ('Hant')
+            ('zh', ['zh-CN'], 'zh-CN'),  # A user selects only the language 'zh' which should end in CN
+            ('fr', ['fr-CA'], 'fr-CA'),  # A user selects only the language 'fr' which should end in fr_CA
+            ('nl', ['nl-BE'], 'nl-BE'),  # A user selects only the language 'fr' which should end in fr_CA
+            # Territory tests
+            ('en', ['en-GB'], 'en-GB'),  # A user selects only a language
+            (
+                'fr',
+                ['fr-FR', 'fr-CA'],
+                'fr-FR',
+            ),  # the engine supports fr_FR and fr_CA since no territory is given, fr_FR takes priority
+        ]
+    )
+    def test_locale_optimized_selected(self, locale: str, locale_list: list[str], expected_locale: str):
+        """
+        Tests from the commit message of 9ae409a05a
 
-        # Assumption:
-        #   A. When a user selects a language the results should be optimized according to
-        #      the selected language.
-        #
-        #   B. When user selects a language and a territory the results should be
-        #      optimized with first priority on territory and second on language.
+        Assumption:
+          A. When a user selects a language the results should be optimized according to
+             the selected language.
+        """
+        self.assertEqual(locales.match_locale(locale, locale_list), expected_locale)
 
-        # Assume we have an engine that supports the following locales:
-        locale_tag_list = ['zh-CN', 'zh-HK', 'nl-BE', 'fr-CA']
+    @parameterized.expand(
+        [
+            ('fr-BE', ['fr-FR', 'fr-CA', 'nl-BE'], 'nl-BE'),  # A user selects region 'fr-BE' which should end in nl-BE
+            ('fr', ['fr-BE', 'fr-CH'], 'fr-BE'),  # A user selects fr with 2 locales,
+            # the get_engine_locale selects the locale by looking at the "population
+            # percent" and this percentage has an higher amount in BE (68.%)
+            # compared to CH (21%)
+        ]
+    )
+    def test_locale_optimized_territory(self, locale: str, locale_list: list[str], expected_locale: str):
+        """
+        Tests from the commit message of 9ae409a05a
 
-        # Examples (Assumption A.)
-        # ------------------------
-
-        # A user selects region 'zh-TW' which should end in zh_HK.
-        # hint: CN is 'Hans' and HK ('Hant') fits better to TW ('Hant')
-        self.assertEqual(locales.match_locale('zh-TW', locale_tag_list), 'zh-HK')
-
-        # A user selects only the language 'zh' which should end in CN
-        self.assertEqual(locales.match_locale('zh', locale_tag_list), 'zh-CN')
-
-        # A user selects only the language 'fr' which should end in fr_CA
-        self.assertEqual(locales.match_locale('fr', locale_tag_list), 'fr-CA')
-
-        # The difference in priority on the territory is best shown with a
-        # engine that supports the following locales:
-        locale_tag_list = ['fr-FR', 'fr-CA', 'en-GB', 'nl-BE']
-
-        # A user selects only a language
-        self.assertEqual(locales.match_locale('en', locale_tag_list), 'en-GB')
-
-        # hint: the engine supports fr_FR and fr_CA since no territory is given,
-        # fr_FR takes priority ..
-        self.assertEqual(locales.match_locale('fr', locale_tag_list), 'fr-FR')
-
-        # Examples (Assumption B.)
-        # ------------------------
-
-        #  A user selects region 'fr-BE' which should end in nl-BE
-        self.assertEqual(locales.match_locale('fr-BE', locale_tag_list), 'nl-BE')
-
-        # If the user selects a language and there are two locales like the
-        # following:
-
-        locale_tag_list = ['fr-BE', 'fr-CH']
-
-        # The get_engine_locale selects the locale by looking at the "population
-        # percent" and this percentage has an higher amount in BE (68.%)
-        # compared to CH (21%)
-
-        self.assertEqual(locales.match_locale('fr', locale_tag_list), 'fr-BE')
+          B. When user selects a language and a territory the results should be
+             optimized with first priority on territory and second on language.
+        """
+        self.assertEqual(locales.match_locale(locale, locale_list), expected_locale)
diff --git a/tests/unit/test_plugins.py b/tests/unit/test_plugins.py
index 72d68ba29..0b89d46fa 100644
--- a/tests/unit/test_plugins.py
+++ b/tests/unit/test_plugins.py
@@ -2,6 +2,7 @@
 # pylint: disable=missing-module-docstring
 
 from mock import Mock
+from parameterized.parameterized import parameterized
 
 from searx import (
     plugins,
@@ -23,143 +24,125 @@ class PluginMock:  # pylint: disable=missing-class-docstring, too-few-public-met
 
 
 class PluginStoreTest(SearxTestCase):  # pylint: disable=missing-class-docstring
-    def test_PluginStore_init(self):
-        store = plugins.PluginStore()
-        self.assertTrue(isinstance(store.plugins, list) and len(store.plugins) == 0)
+    def setUp(self):
+        self.store = plugins.PluginStore()
 
-    def test_PluginStore_register(self):
-        store = plugins.PluginStore()
+    def test_init(self):
+        self.assertEqual(0, len(self.store.plugins))
+        self.assertIsInstance(self.store.plugins, list)
+
+    def test_register(self):
         testplugin = PluginMock()
-        store.register(testplugin)
+        self.store.register(testplugin)
+        self.assertEqual(1, len(self.store.plugins))
 
-        self.assertTrue(len(store.plugins) == 1)
+    def test_call_empty(self):
+        testplugin = PluginMock()
+        self.store.register(testplugin)
+        setattr(testplugin, 'asdf', Mock())
+        request = Mock()
+        self.store.call([], 'asdf', request, Mock())
+        self.assertFalse(getattr(testplugin, 'asdf').called)  # pylint: disable=E1101
 
-    def test_PluginStore_call(self):
+    def test_call_with_plugin(self):
         store = plugins.PluginStore()
         testplugin = PluginMock()
         store.register(testplugin)
         setattr(testplugin, 'asdf', Mock())
         request = Mock()
-        store.call([], 'asdf', request, Mock())
-
-        self.assertFalse(testplugin.asdf.called)  # pylint: disable=E1101
-
         store.call([testplugin], 'asdf', request, Mock())
-        self.assertTrue(testplugin.asdf.called)  # pylint: disable=E1101
+        self.assertTrue(getattr(testplugin, 'asdf').called)  # pylint: disable=E1101
 
 
-class SelfIPTest(SearxTestCase):  # pylint: disable=missing-class-docstring
-    def test_PluginStore_init(self):
+class PluginIPSelfInfo(SearxTestCase):  # pylint: disable=missing-class-docstring
+    def setUp(self):
         plugin = plugins.load_and_initialize_plugin('searx.plugins.self_info', False, (None, {}))
-        store = plugins.PluginStore()
-        store.register(plugin)
+        self.store = plugins.PluginStore()
+        self.store.register(plugin)
         cfg = limiter.get_cfg()
         botdetection.init(cfg, None)
 
-        self.assertTrue(len(store.plugins) == 1)
+    def test_plugin_store_init(self):
+        self.assertEqual(1, len(self.store.plugins))
 
-        # IP test
+    def test_ip_in_answer(self):
         request = Mock()
         request.remote_addr = '127.0.0.1'
         request.headers = {'X-Forwarded-For': '1.2.3.4, 127.0.0.1', 'X-Real-IP': '127.0.0.1'}
-        search = get_search_mock(
-            query='ip',
-            pageno=1,
-        )
-        store.call(store.plugins, 'post_search', request, search)
-        self.assertTrue('127.0.0.1' in search.result_container.answers["ip"]["answer"])
+        search = get_search_mock(query='ip', pageno=1)
+        self.store.call(self.store.plugins, 'post_search', request, search)
+        self.assertIn('127.0.0.1', search.result_container.answers["ip"]["answer"])
 
+    def test_ip_not_in_answer(self):
+        request = Mock()
+        request.remote_addr = '127.0.0.1'
+        request.headers = {'X-Forwarded-For': '1.2.3.4, 127.0.0.1', 'X-Real-IP': '127.0.0.1'}
         search = get_search_mock(query='ip', pageno=2)
-        store.call(store.plugins, 'post_search', request, search)
-        self.assertFalse('ip' in search.result_container.answers)
+        self.store.call(self.store.plugins, 'post_search', request, search)
+        self.assertNotIn('ip', search.result_container.answers)
 
-        # User agent test
+    @parameterized.expand(
+        [
+            'user-agent',
+            'What is my User-Agent?',
+        ]
+    )
+    def test_user_agent_in_answer(self, query: str):
         request = Mock(user_agent=Mock(string='Mock'))
+        search = get_search_mock(query=query, pageno=1)
+        self.store.call(self.store.plugins, 'post_search', request, search)
+        self.assertIn('Mock', search.result_container.answers["user-agent"]["answer"])
 
-        search = get_search_mock(query='user-agent', pageno=1)
-        store.call(store.plugins, 'post_search', request, search)
-        self.assertTrue('Mock' in search.result_container.answers["user-agent"]["answer"])
-
-        search = get_search_mock(query='user-agent', pageno=2)
-        store.call(store.plugins, 'post_search', request, search)
-        self.assertFalse('user-agent' in search.result_container.answers)
-
-        search = get_search_mock(query='user-agent', pageno=1)
-        store.call(store.plugins, 'post_search', request, search)
-        self.assertTrue('Mock' in search.result_container.answers["user-agent"]["answer"])
-
-        search = get_search_mock(query='user-agent', pageno=2)
-        store.call(store.plugins, 'post_search', request, search)
-        self.assertFalse('user-agent' in search.result_container.answers)
-
-        search = get_search_mock(query='What is my User-Agent?', pageno=1)
-        store.call(store.plugins, 'post_search', request, search)
-        self.assertTrue('Mock' in search.result_container.answers["user-agent"]["answer"])
-
-        search = get_search_mock(query='What is my User-Agent?', pageno=2)
-        store.call(store.plugins, 'post_search', request, search)
-        self.assertFalse('user-agent' in search.result_container.answers)
+    @parameterized.expand(
+        [
+            'user-agent',
+            'What is my User-Agent?',
+        ]
+    )
+    def test_user_agent_not_in_answer(self, query: str):
+        request = Mock(user_agent=Mock(string='Mock'))
+        search = get_search_mock(query=query, pageno=2)
+        self.store.call(self.store.plugins, 'post_search', request, search)
+        self.assertNotIn('user-agent', search.result_container.answers)
 
 
-class HashPluginTest(SearxTestCase):  # pylint: disable=missing-class-docstring
-    def test_PluginStore_init(self):
-        store = plugins.PluginStore()
+class PluginHashTest(SearxTestCase):  # pylint: disable=missing-class-docstring
+    def setUp(self):
+        self.store = plugins.PluginStore()
         plugin = plugins.load_and_initialize_plugin('searx.plugins.hash_plugin', False, (None, {}))
-        store.register(plugin)
+        self.store.register(plugin)
 
-        self.assertTrue(len(store.plugins) == 1)
+    def test_plugin_store_init(self):
+        self.assertEqual(1, len(self.store.plugins))
 
+    @parameterized.expand(
+        [
+            ('md5 test', 'md5 hash digest: 098f6bcd4621d373cade4e832627b4f6'),
+            ('sha1 test', 'sha1 hash digest: a94a8fe5ccb19ba61c4c0873d391e987982fbbd3'),
+            ('sha224 test', 'sha224 hash digest: 90a3ed9e32b2aaf4c61c410eb925426119e1a9dc53d4286ade99a809'),
+            ('sha256 test', 'sha256 hash digest: 9f86d081884c7d659a2feaa0c55ad015a3bf4f1b2b0b822cd15d6c15b0f00a08'),
+            (
+                'sha384 test',
+                'sha384 hash digest: 768412320f7b0aa5812fce428dc4706b3c'
+                'ae50e02a64caa16a782249bfe8efc4b7ef1ccb126255d196047dfedf1'
+                '7a0a9',
+            ),
+            (
+                'sha512 test',
+                'sha512 hash digest: ee26b0dd4af7e749aa1a8ee3c10ae9923f6'
+                '18980772e473f8819a5d4940e0db27ac185f8a0e1d5f84f88bc887fd67b143732c304cc5'
+                'fa9ad8e6f57f50028a8ff',
+            ),
+        ]
+    )
+    def test_hash_digest_new(self, query: str, hash_str: str):
         request = Mock(remote_addr='127.0.0.1')
+        search = get_search_mock(query=query, pageno=1)
+        self.store.call(self.store.plugins, 'post_search', request, search)
+        self.assertIn(hash_str, search.result_container.answers['hash']['answer'])
 
-        # MD5
-        search = get_search_mock(query='md5 test', pageno=1)
-        store.call(store.plugins, 'post_search', request, search)
-        self.assertTrue(
-            'md5 hash digest: 098f6bcd4621d373cade4e832627b4f6' in search.result_container.answers['hash']['answer']
-        )
-
+    def test_md5_bytes_no_answer(self):
+        request = Mock(remote_addr='127.0.0.1')
         search = get_search_mock(query=b'md5 test', pageno=2)
-        store.call(store.plugins, 'post_search', request, search)
-        self.assertFalse('hash' in search.result_container.answers)
-
-        # SHA1
-        search = get_search_mock(query='sha1 test', pageno=1)
-        store.call(store.plugins, 'post_search', request, search)
-        self.assertTrue(
-            'sha1 hash digest: a94a8fe5ccb19ba61c4c0873d391e9879'
-            '82fbbd3' in search.result_container.answers['hash']['answer']
-        )
-
-        # SHA224
-        search = get_search_mock(query='sha224 test', pageno=1)
-        store.call(store.plugins, 'post_search', request, search)
-        self.assertTrue(
-            'sha224 hash digest: 90a3ed9e32b2aaf4c61c410eb9254261'
-            '19e1a9dc53d4286ade99a809' in search.result_container.answers['hash']['answer']
-        )
-
-        # SHA256
-        search = get_search_mock(query='sha256 test', pageno=1)
-        store.call(store.plugins, 'post_search', request, search)
-        self.assertTrue(
-            'sha256 hash digest: 9f86d081884c7d659a2feaa0c55ad015a'
-            '3bf4f1b2b0b822cd15d6c15b0f00a08' in search.result_container.answers['hash']['answer']
-        )
-
-        # SHA384
-        search = get_search_mock(query='sha384 test', pageno=1)
-        store.call(store.plugins, 'post_search', request, search)
-        self.assertTrue(
-            'sha384 hash digest: 768412320f7b0aa5812fce428dc4706b3c'
-            'ae50e02a64caa16a782249bfe8efc4b7ef1ccb126255d196047dfedf1'
-            '7a0a9' in search.result_container.answers['hash']['answer']
-        )
-
-        # SHA512
-        search = get_search_mock(query='sha512 test', pageno=1)
-        store.call(store.plugins, 'post_search', request, search)
-        self.assertTrue(
-            'sha512 hash digest: ee26b0dd4af7e749aa1a8ee3c10ae9923f6'
-            '18980772e473f8819a5d4940e0db27ac185f8a0e1d5f84f88bc887fd67b143732c304cc5'
-            'fa9ad8e6f57f50028a8ff' in search.result_container.answers['hash']['answer']
-        )
+        self.store.call(self.store.plugins, 'post_search', request, search)
+        self.assertNotIn('hash', search.result_container.answers)
diff --git a/tests/unit/test_preferences.py b/tests/unit/test_preferences.py
index 5855c12a6..8bf157a7e 100644
--- a/tests/unit/test_preferences.py
+++ b/tests/unit/test_preferences.py
@@ -1,6 +1,7 @@
 # SPDX-License-Identifier: AGPL-3.0-or-later
 # pylint: disable=missing-module-docstring, invalid-name
 
+from tests import SearxTestCase
 from searx.locales import locales_initialize
 from searx.preferences import (
     EnumStringSetting,
@@ -10,12 +11,12 @@ from searx.preferences import (
     PluginsSetting,
     ValidationException,
 )
-from tests import SearxTestCase
+from searx.plugins import Plugin
 
 locales_initialize()
 
 
-class PluginStub:  # pylint: disable=missing-class-docstring, too-few-public-methods
+class PluginStub(Plugin):  # pylint: disable=missing-class-docstring, too-few-public-methods
     def __init__(self, plugin_id, default_on):
         self.id = plugin_id
         self.default_on = default_on
@@ -47,22 +48,22 @@ class TestSettings(SearxTestCase):  # pylint: disable=missing-class-docstring
 
     def test_enum_setting_invalid_default_value(self):
         with self.assertRaises(ValidationException):
-            EnumStringSetting(3, choices=[0, 1, 2])
+            EnumStringSetting('3', choices=['0', '1', '2'])
 
     def test_enum_setting_invalid_choice(self):
-        setting = EnumStringSetting(0, choices=[0, 1, 2])
+        setting = EnumStringSetting('0', choices=['0', '1', '2'])
         with self.assertRaises(ValidationException):
-            setting.parse(3)
+            setting.parse('3')
 
     def test_enum_setting_valid_default(self):
-        setting = EnumStringSetting(3, choices=[1, 2, 3])
-        self.assertEqual(setting.get_value(), 3)
+        setting = EnumStringSetting('3', choices=['1', '2', '3'])
+        self.assertEqual(setting.get_value(), '3')
 
     def test_enum_setting_valid_choice(self):
-        setting = EnumStringSetting(3, choices=[1, 2, 3])
-        self.assertEqual(setting.get_value(), 3)
-        setting.parse(2)
-        self.assertEqual(setting.get_value(), 2)
+        setting = EnumStringSetting('3', choices=['1', '2', '3'])
+        self.assertEqual(setting.get_value(), '3')
+        setting.parse('2')
+        self.assertEqual(setting.get_value(), '2')
 
     # multiple choice settings
 
diff --git a/tests/unit/test_query.py b/tests/unit/test_query.py
index 46613a6e1..601a6e60d 100644
--- a/tests/unit/test_query.py
+++ b/tests/unit/test_query.py
@@ -1,6 +1,7 @@
 # SPDX-License-Identifier: AGPL-3.0-or-later
 # pylint: disable=missing-module-docstring
 
+from parameterized.parameterized import parameterized
 from searx.engines import load_engines
 from searx.query import RawTextQuery
 from tests import SearxTestCase
@@ -129,49 +130,32 @@ class TestLanguageParser(SearxTestCase):  # pylint:disable=missing-class-docstri
         query = RawTextQuery(query_text, [])
         self.assertEqual(query.autocomplete_list, [":en", ":en_us", ":english", ":united_kingdom"])
 
-    def test_autocomplete(self):
-        query = RawTextQuery(':englis', [])
-        self.assertEqual(query.autocomplete_list, [":english"])
-
-        query = RawTextQuery(':deutschla', [])
-        self.assertEqual(query.autocomplete_list, [":deutschland"])
-
-        query = RawTextQuery(':new_zea', [])
-        self.assertEqual(query.autocomplete_list, [":new_zealand"])
-
-        query = RawTextQuery(':hu-H', [])
-        self.assertEqual(query.autocomplete_list, [":hu-hu"])
-
-        query = RawTextQuery(':zh-', [])
-        self.assertEqual(query.autocomplete_list, [':zh-cn', ':zh-hk', ':zh-tw'])
+    @parameterized.expand(
+        [
+            (':englis', [":english"]),
+            (':deutschla', [":deutschland"]),
+            (':new_zea', [":new_zealand"]),
+            (':zh-', [':zh-cn', ':zh-hk', ':zh-tw']),
+        ]
+    )
+    def test_autocomplete(self, query: str, autocomplete_list: list):
+        query = RawTextQuery(query, [])
+        self.assertEqual(query.autocomplete_list, autocomplete_list)
 
 
 class TestTimeoutParser(SearxTestCase):  # pylint:disable=missing-class-docstring
-    def test_timeout_below100(self):
-        query_text = '<3 the query'
+    @parameterized.expand(
+        [
+            ('<3 the query', 3),
+            ('<350 the query', 0.35),
+            ('<3500 the query', 3.5),
+        ]
+    )
+    def test_timeout_limit(self, query_text: str, timeout_limit: float):
         query = RawTextQuery(query_text, [])
-
         self.assertEqual(query.getFullQuery(), query_text)
         self.assertEqual(len(query.query_parts), 1)
-        self.assertEqual(query.timeout_limit, 3)
-        self.assertFalse(query.specific)
-
-    def test_timeout_above100(self):
-        query_text = '<350 the query'
-        query = RawTextQuery(query_text, [])
-
-        self.assertEqual(query.getFullQuery(), query_text)
-        self.assertEqual(len(query.query_parts), 1)
-        self.assertEqual(query.timeout_limit, 0.35)
-        self.assertFalse(query.specific)
-
-    def test_timeout_above1000(self):
-        query_text = '<3500 the query'
-        query = RawTextQuery(query_text, [])
-
-        self.assertEqual(query.getFullQuery(), query_text)
-        self.assertEqual(len(query.query_parts), 1)
-        self.assertEqual(query.timeout_limit, 3.5)
+        self.assertEqual(query.timeout_limit, timeout_limit)
         self.assertFalse(query.specific)
 
     def test_timeout_invalid(self):
@@ -182,7 +166,7 @@ class TestTimeoutParser(SearxTestCase):  # pylint:disable=missing-class-docstrin
         self.assertEqual(query.getFullQuery(), query_text)
         self.assertEqual(len(query.query_parts), 0)
         self.assertEqual(query.getQuery(), query_text)
-        self.assertEqual(query.timeout_limit, None)
+        self.assertIsNone(query.timeout_limit)
         self.assertFalse(query.specific)
 
     def test_timeout_autocomplete(self):
@@ -193,7 +177,7 @@ class TestTimeoutParser(SearxTestCase):  # pylint:disable=missing-class-docstrin
         self.assertEqual(query.getFullQuery(), query_text)
         self.assertEqual(len(query.query_parts), 0)
         self.assertEqual(query.getQuery(), query_text)
-        self.assertEqual(query.timeout_limit, None)
+        self.assertIsNone(query.timeout_limit)
         self.assertFalse(query.specific)
         self.assertEqual(query.autocomplete_list, ['<3', '<850'])
 
@@ -212,7 +196,7 @@ class TestExternalBangParser(SearxTestCase):  # pylint:disable=missing-class-doc
         query = RawTextQuery(query_text, [])
 
         self.assertEqual(query.getFullQuery(), query_text)
-        self.assertEqual(query.external_bang, None)
+        self.assertIsNone(query.external_bang)
         self.assertFalse(query.specific)
 
     def test_external_bang_autocomplete(self):
@@ -239,23 +223,22 @@ class TestBang(SearxTestCase):  # pylint:disable=missing-class-docstring
     def tearDown(self):
         load_engines([])
 
-    def test_bang(self):
+    @parameterized.expand(SPECIFIC_BANGS)
+    def test_bang(self, bang: str):
+        with self.subTest(msg="Check bang", bang=bang):
+            query_text = TestBang.THE_QUERY + ' ' + bang
+            query = RawTextQuery(query_text, [])
 
-        for bang in TestBang.SPECIFIC_BANGS:
-            with self.subTest(msg="Check bang", bang=bang):
-                query_text = TestBang.THE_QUERY + ' ' + bang
-                query = RawTextQuery(query_text, [])
+            self.assertEqual(query.getFullQuery(), bang + ' ' + TestBang.THE_QUERY)
+            self.assertEqual(query.query_parts, [bang])
+            self.assertEqual(query.user_query_parts, TestBang.THE_QUERY.split(' '))
 
-                self.assertEqual(query.getFullQuery(), bang + ' ' + TestBang.THE_QUERY)
-                self.assertEqual(query.query_parts, [bang])
-                self.assertEqual(query.user_query_parts, TestBang.THE_QUERY.split(' '))
-
-    def test_specific(self):
-        for bang in TestBang.SPECIFIC_BANGS:
-            with self.subTest(msg="Check bang is specific", bang=bang):
-                query_text = TestBang.THE_QUERY + ' ' + bang
-                query = RawTextQuery(query_text, [])
-                self.assertTrue(query.specific)
+    @parameterized.expand(SPECIFIC_BANGS)
+    def test_specific(self, bang: str):
+        with self.subTest(msg="Check bang is specific", bang=bang):
+            query_text = TestBang.THE_QUERY + ' ' + bang
+            query = RawTextQuery(query_text, [])
+            self.assertTrue(query.specific)
 
     def test_bang_not_found(self):
         query = RawTextQuery('the query !bang_not_found', [])
diff --git a/tests/unit/test_search.py b/tests/unit/test_search.py
index a60089aef..be95fb08e 100644
--- a/tests/unit/test_search.py
+++ b/tests/unit/test_search.py
@@ -110,7 +110,7 @@ class SearchTestCase(SearxTestCase):  # pylint: disable=missing-class-docstring
             search.search()
         self.assertEqual(search.actual_timeout, 10.0)
 
-    def test_external_bang(self):
+    def test_external_bang_valid(self):
         search_query = SearchQuery(
             'yes yes',
             [EngineRef(PUBLIC_ENGINE_NAME, 'general')],
@@ -124,8 +124,9 @@ class SearchTestCase(SearxTestCase):  # pylint: disable=missing-class-docstring
         search = searx.search.Search(search_query)
         results = search.search()
         # For checking if the user redirected with the youtube external bang
-        self.assertTrue(results.redirect_url is not None)
+        self.assertIsNotNone(results.redirect_url)
 
+    def test_external_bang_none(self):
         search_query = SearchQuery(
             'youtube never gonna give you up',
             [EngineRef(PUBLIC_ENGINE_NAME, 'general')],
@@ -140,4 +141,4 @@ class SearchTestCase(SearxTestCase):  # pylint: disable=missing-class-docstring
         with self.app.test_request_context('/search'):
             results = search.search()
         # This should not redirect
-        self.assertTrue(results.redirect_url is None)
+        self.assertIsNone(results.redirect_url)
diff --git a/tests/unit/test_settings_loader.py b/tests/unit/test_settings_loader.py
index 281b11c16..99baee1ca 100644
--- a/tests/unit/test_settings_loader.py
+++ b/tests/unit/test_settings_loader.py
@@ -6,6 +6,8 @@ from pathlib import Path
 import os
 from unittest.mock import patch
 
+from parameterized import parameterized
+
 from searx.exceptions import SearxSettingsException
 from searx import settings_loader
 from tests import SearxTestCase
@@ -31,13 +33,13 @@ class TestDefaultSettings(SearxTestCase):  # pylint: disable=missing-class-docst
         settings, msg = settings_loader.load_settings(load_user_settings=False)
         self.assertTrue(msg.startswith('load the default settings from'))
         self.assertFalse(settings['general']['debug'])
-        self.assertTrue(isinstance(settings['general']['instance_name'], str))
+        self.assertIsInstance(settings['general']['instance_name'], str)
         self.assertEqual(settings['server']['secret_key'], "ultrasecretkey")
-        self.assertTrue(isinstance(settings['server']['port'], int))
-        self.assertTrue(isinstance(settings['server']['bind_address'], str))
-        self.assertTrue(isinstance(settings['engines'], list))
-        self.assertTrue(isinstance(settings['doi_resolvers'], dict))
-        self.assertTrue(isinstance(settings['default_doi_resolver'], str))
+        self.assertIsInstance(settings['server']['port'], int)
+        self.assertIsInstance(settings['server']['bind_address'], str)
+        self.assertIsInstance(settings['engines'], list)
+        self.assertIsInstance(settings['doi_resolvers'], dict)
+        self.assertIsInstance(settings['default_doi_resolver'], str)
 
 
 class TestUserSettings(SearxTestCase):  # pylint: disable=missing-class-docstring
@@ -50,11 +52,14 @@ class TestUserSettings(SearxTestCase):  # pylint: disable=missing-class-docstrin
         with self.assertRaises(ValueError):
             self.assertFalse(settings_loader.is_use_default_settings({'use_default_settings': 0}))
 
-    def test_user_settings_not_found(self):
-        with patch.dict(os.environ, {'SEARXNG_SETTINGS_PATH': _settings("not_exists.yml")}):
-            with self.assertRaises(EnvironmentError):
-                _s, _m = settings_loader.load_settings()
-        with patch.dict(os.environ, {'SEARXNG_SETTINGS_PATH': "/folder/not/exists"}):
+    @parameterized.expand(
+        [
+            _settings("not_exists.yml"),
+            "/folder/not/exists",
+        ]
+    )
+    def test_user_settings_not_found(self, path: str):
+        with patch.dict(os.environ, {'SEARXNG_SETTINGS_PATH': path}):
             with self.assertRaises(EnvironmentError):
                 _s, _m = settings_loader.load_settings()
 
diff --git a/tests/unit/test_utils.py b/tests/unit/test_utils.py
index 1a6fba46d..4306d0790 100644
--- a/tests/unit/test_utils.py
+++ b/tests/unit/test_utils.py
@@ -3,6 +3,7 @@
 
 import lxml.etree
 from lxml import html
+from parameterized.parameterized import parameterized
 
 from searx.exceptions import SearxXPathSyntaxException, SearxEngineXPathException
 from searx import utils
@@ -66,9 +67,15 @@ class TestUtils(SearxTestCase):  # pylint: disable=missing-class-docstring
         self.assertEqual(utils.extract_text(dom.xpath('boolean(//span)')), 'True')
         self.assertEqual(utils.extract_text(dom.xpath('//img/@src')), 'test.jpg')
         self.assertEqual(utils.extract_text(dom.xpath('//unexistingtag')), '')
+
+    def test_extract_text_allow_none(self):
         self.assertEqual(utils.extract_text(None, allow_none=True), None)
+
+    def test_extract_text_error_none(self):
         with self.assertRaises(ValueError):
             utils.extract_text(None)
+
+    def test_extract_text_error_empty(self):
         with self.assertRaises(ValueError):
             utils.extract_text({})
 
@@ -103,14 +110,16 @@ class TestHTMLTextExtractor(SearxTestCase):  # pylint: disable=missing-class-doc
     def test__init__(self):
         self.assertEqual(self.html_text_extractor.result, [])
 
-    def test_handle_charref(self):
-        self.html_text_extractor.handle_charref('xF')
-        self.assertIn('\x0f', self.html_text_extractor.result)
-        self.html_text_extractor.handle_charref('XF')
-        self.assertIn('\x0f', self.html_text_extractor.result)
-
-        self.html_text_extractor.handle_charref('97')
-        self.assertIn('a', self.html_text_extractor.result)
+    @parameterized.expand(
+        [
+            ('xF', '\x0f'),
+            ('XF', '\x0f'),
+            ('97', 'a'),
+        ]
+    )
+    def test_handle_charref(self, charref: str, expected: str):
+        self.html_text_extractor.handle_charref(charref)
+        self.assertIn(expected, self.html_text_extractor.result)
 
     def test_handle_entityref(self):
         entity = 'test'
@@ -191,7 +200,7 @@ class TestXPathUtils(SearxTestCase):  # pylint: disable=missing-class-docstring
         self.assertEqual(utils.eval_xpath_getindex(doc, '//i/text()', 1, default='something'), 'something')
 
         # default is None
-        self.assertEqual(utils.eval_xpath_getindex(doc, '//i/text()', 1, default=None), None)
+        self.assertIsNone(utils.eval_xpath_getindex(doc, '//i/text()', 1, default=None))
 
         # index not found
         with self.assertRaises(SearxEngineXPathException) as context:
diff --git a/tests/unit/test_webutils.py b/tests/unit/test_webutils.py
index c6c441dab..cf9da5f10 100644
--- a/tests/unit/test_webutils.py
+++ b/tests/unit/test_webutils.py
@@ -2,52 +2,59 @@
 # pylint: disable=missing-module-docstring
 
 import mock
+from parameterized.parameterized import parameterized
 from searx import webutils
 from tests import SearxTestCase
 
 
 class TestWebUtils(SearxTestCase):  # pylint: disable=missing-class-docstring
-    def test_prettify_url(self):
-        data = (
+
+    @parameterized.expand(
+        [
             ('https://searx.me/', 'https://searx.me/'),
             ('https://searx.me/ű', 'https://searx.me/ű'),
             ('https://searx.me/' + (100 * 'a'), 'https://searx.me/[...]aaaaaaaaaaaaaaaaa'),
             ('https://searx.me/' + (100 * 'ű'), 'https://searx.me/[...]űűűűűűűűűűűűűűűűű'),
-        )
+        ]
+    )
+    def test_prettify_url(self, test_url: str, expected: str):
+        self.assertEqual(webutils.prettify_url(test_url, max_length=32), expected)
 
-        for test_url, expected in data:
-            self.assertEqual(webutils.prettify_url(test_url, max_length=32), expected)
+    @parameterized.expand(
+        [
+            (0, None, None),
+            (None, None, None),
+            ('', None, None),
+            (False, None, None),
+        ]
+    )
+    def test_highlight_content_none(self, content, query, expected):
+        self.assertEqual(webutils.highlight_content(content, query), expected)
 
-    def test_highlight_content(self):
-        self.assertEqual(webutils.highlight_content(0, None), None)
-        self.assertEqual(webutils.highlight_content(None, None), None)
-        self.assertEqual(webutils.highlight_content('', None), None)
-        self.assertEqual(webutils.highlight_content(False, None), None)
+    def test_highlight_content_same(self):
+        content = '<html></html>not<'
+        self.assertEqual(webutils.highlight_content(content, None), content)
 
-        contents = ['<html></html>not<']
-        for content in contents:
-            self.assertEqual(webutils.highlight_content(content, None), content)
-
-        content = 'a'
-        query = 'test'
-        self.assertEqual(webutils.highlight_content(content, query), 'a')
-        query = 'a test'
-        self.assertEqual(webutils.highlight_content(content, query), '<span class="highlight">a</span>')
-
-        # pylint: disable=line-too-long
-        data = (
+    @parameterized.expand(
+        [
+            ('test', 'a', 'a'),
+            ('a test', 'a', '<span class="highlight">a</span>'),
             ('" test "', 'a test string', 'a <span class="highlight">test</span> string'),
             ('"a"', 'this is a test string', 'this is <span class="highlight">a</span> test string'),
             (
                 'a test',
                 'this is a test string that matches entire query',
-                'this is <span class="highlight">a</span> <span class="highlight">test</span> string that matches entire query',
+                'this is <span class="highlight">a</span>'
+                ' <span class="highlight">test</span>'
+                ' string that matches entire query',
             ),
             (
                 'this a test',
                 'this is a string to test.',
                 (
-                    '<span class="highlight">this</span> is <span class="highlight">a</span> string to <span class="highlight">test</span>.'
+                    '<span class="highlight">this</span>'
+                    ' is <span class="highlight">a</span>'
+                    ' string to <span class="highlight">test</span>.'
                 ),
             ),
             (
@@ -65,9 +72,10 @@ class TestWebUtils(SearxTestCase):  # pylint: disable=missing-class-docstring
                 'a string with class.',
                 '<span class="highlight">a</span> string with <span class="highlight">class</span>.',
             ),
-        )
-        for query, content, expected in data:
-            self.assertEqual(webutils.highlight_content(content, query), expected)
+        ]
+    )
+    def test_highlight_content_equal(self, query: str, content: str, expected: str):
+        self.assertEqual(webutils.highlight_content(content, query), expected)
 
 
 class TestUnicodeWriter(SearxTestCase):  # pylint: disable=missing-class-docstring
@@ -76,7 +84,7 @@ class TestUnicodeWriter(SearxTestCase):  # pylint: disable=missing-class-docstri
 
     def test_write_row(self):
         row = [1, 2, 3]
-        self.assertEqual(self.unicode_writer.writerow(row), None)
+        self.assertIsNone(self.unicode_writer.writerow(row))
 
     def test_write_rows(self):
         self.unicode_writer.writerow = mock.MagicMock()
@@ -86,13 +94,18 @@ class TestUnicodeWriter(SearxTestCase):  # pylint: disable=missing-class-docstri
 
 
 class TestNewHmac(SearxTestCase):  # pylint: disable=missing-class-docstring
-    def test_bytes(self):
+    @parameterized.expand(
+        [
+            b'secret',
+            1,
+        ]
+    )
+    def test_attribute_error(self, secret_key):
         data = b'http://example.com'
         with self.assertRaises(AttributeError):
-            webutils.new_hmac(b'secret', data)
-
-        with self.assertRaises(AttributeError):
-            webutils.new_hmac(1, data)
+            webutils.new_hmac(secret_key, data)
 
+    def test_bytes(self):
+        data = b'http://example.com'
         res = webutils.new_hmac('secret', data)
         self.assertEqual(res, '23e2baa2404012a5cc8e4a18b4aabf0dde4cb9b56f679ddc0fd6d7c24339d819')