[refactor] unit tests to utilize paramaterized and break down monolithic tests

- for tests which perform the same arrange/act/assert pattern but with different
  data, the data portion has been moved to the ``paramaterized.expand`` fields

- for monolithic tests which performed multiple arrange/act/asserts,
  they have been broken up into different unit tests.

- when possible, change generic assert statements to more concise
  asserts (i.e. ``assertIsNone``)

This work ultimately is focused on creating smaller and more concise tests.
While paramaterized may make adding new configurations for existing tests
easier, that is just a beneficial side effect.  The main benefit is that smaller
tests are easier to reason about, meaning they are easier to debug when they
start failing.  This improves the developer experience in debugging what went
wrong when refactoring the project.

Total number of tests went from 192 -> 259; or, broke apart larger tests into 69
more concise ones.

1 files changed, 94 insertions, 111 deletions

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)
-
-        # User agent test
+        self.store.call(self.store.plugins, 'post_search', request, search)
+        self.assertNotIn('ip', search.result_container.answers)
+
+    @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='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)
+        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"])
+
+    @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.assertTrue(len(store.plugins) == 1)
-
+        self.store.register(plugin)
+
+    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)