Update outdated class references from Drupal\*\Tests to Drupal\Tests\*

Proposed automation:
In PHPStorm do a replace in file
Find with regex: \\Drupal\\(\w+)\\Tests\\
Replace with : \\Drupal\\Tests\\$1\\

Lets see if this breaks anything

Tagging for the PHPUnit initiative since we should have changed it then ;)

Lets try that again with the trailing slashes added

Yeah good point, it does provide a handy list of what needs to be checked I guess.

Manually went through them and added what needed to be added. Reverted a couple that still use the old namespaces (in Views mostly), removed some things that no longer seem to exist

Ran this locally and found these instances. Could you confirm if they are no relevant to this

Targets
    Occurrences of '\\Drupal\\.*\\Tests\\' in Directory /Users/smustgrave/Sites/Drupal-Demos/drupal-10.x/web/core
Found Occurrences in Directory /Users/smustgrave/Sites/Drupal-Demos/drupal-10.x/web/core  (23 usages found)
    Unclassified  (3 usages found)
        drupal-10.x  (3 usages found)
            web/core  (3 usages found)
                phpstan-baseline.neon  (3 usages found)
                    3159 e 'ClassWithConstants\\.SOME_KEY' \\(\\\\Drupal\\\\Tests\\\\Component\\\\Annotation\\\\Doctrine\\\\Fixtures\\\\ClassWithConstants\\:\\:SOME_KEY, \\\\Drupal\\\\Tests\\\\Component\\\\Annotation\\\\Doctrine\\\\Fixtures\\\\ClassWithConstants\\:\\:SOME_KEY\\)\\.$#"
                    3264 			message: "#^\\#lazy_builder callback '\\\\\\\\Drupal\\\\\\\\Tests\\\\\\\\Core…' at key '0' is not trusted\\.$#"
                    3274 			message: "#^\\#pre_render callback '\\\\\\\\Drupal\\\\\\\\Tests\\\\\\\\Core…' at key '0' is not trusted\\.$#"
    Usage in comments  (9 usages found)
        drupal-10.x  (9 usages found)
            web/core/modules/views/tests/modules/views_entity_test  (1 usage found)
                views_entity_test.module  (1 usage found)
                    58 // \Drupal\views\Tests\ViewResultAssertionTrait::assertIdenticalResultsetHelper()
            web/core/modules/views/tests/src/Functional/Handler  (2 usages found)
                AreaTitleWebTest.php  (2 usages found)
                    57 // \Drupal\views\Tests\ViewTestData::dataSet().
                    76 // \Drupal\views\Tests\ViewTestData::dataSet().
            web/core/modules/views/tests/src/Unit  (1 usage found)
                PluginBaseTest.php  (1 usage found)
                    17 * @var \Drupal\views\Tests\TestHelperPlugin
            web/core/modules/views/tests/src/Unit/EventSubscriber  (1 usage found)
                RouteSubscriberTest.php  (1 usage found)
                    40 * @var \Drupal\views\EventSubscriber\RouteSubscriber|\Drupal\Tests\views\Unit\EventSubscriber\TestRouteSubscriber
            web/core/tests/Drupal/KernelTests/Core/Plugin/Condition  (1 usage found)
                RequestPathTest.php  (1 usage found)
                    29 * @var \Drupal\system\Tests\Routing\MockAliasManager
            web/core/tests/Drupal/Tests/Core/Asset  (1 usage found)
                LibraryDiscoveryParserTest.php  (1 usage found)
                    30 * @var \Drupal\Core\Asset\LibraryDiscoveryParser|\Drupal\Tests\Core\Asset\TestLibraryDiscoveryParser
            web/core/tests/Drupal/Tests/Core/EventSubscriber  (1 usage found)
                CustomPageExceptionHtmlSubscriberTest.php  (1 usage found)
                    57 * @var \Drupal\Core\EventSubscriber\CustomPageExceptionHtmlSubscriber|\Drupal\Tests\Core\EventSubscriber\CustomPageExceptionHtmlSubscriberTest
            web/core/tests/Drupal/Tests/Core/Extension  (1 usage found)
                ThemeHandlerTest.php  (1 usage found)
                    39 * @var \Drupal\Core\Extension\ThemeHandler|\Drupal\Tests\Core\Extension\StubThemeHandler
    Usage in string constants  (11 usages found)
        drupal-10.x  (11 usages found)
            web/core/modules/rest/tests/src/Kernel/EntityResource  (1 usage found)
                EntityResourceRestTestCoverageTest.php  (1 usage found)
                    96 $class_alternative = str_replace("\\Drupal\\Tests\\$module_name\\Functional", '\Drupal\FunctionalTests', $class);
            web/core/tests/Drupal/Tests/Component/Assertion  (2 usages found)
                InspectorTest.php  (2 usages found)
                    235 $this->assertTrue(Inspector::assertAllObjects([new \ArrayObject(), new StringObject()], '\\Traversable', '\\Drupal\\Tests\\Component\\Assertion\\StringObject'));
                    236 $this->assertFalse(Inspector::assertAllObjects([new \ArrayObject(), new StringObject(), new \stdClass()], '\\ArrayObject', '\\Drupal\\Tests\\Component\\Assertion\\StringObject'));
            web/core/tests/Drupal/Tests/Component/ProxyBuilder  (1 usage found)
                ProxyBuilderTest.php  (1 usage found)
                    302 public function typehintSelf(?\Drupal\Tests\Component\ProxyBuilder\TestServiceNullableTypehintSelf $parameter): ?\Drupal\Tests\Component\ProxyBuilder\TestServiceNullableTypehintSelf
            web/core/tests/Drupal/Tests/Core/Render  (5 usages found)
                RendererCallbackTest.php  (5 usages found)
                    46 t be methods of a class that implements \Drupal\Core\Security\TrustedCallbackInterface or be an anonymous function. The callback was \Drupal\Tests\Core\Render\callback. See https://www.drupal.org/node/2966725',
                    50 t be methods of a class that implements \Drupal\Core\Security\TrustedCallbackInterface or be an anonymous function. The callback was \Drupal\Tests\Core\Render\RendererCallbackTest::renderCallback. See https://www.drupal.org/node/2966725',
                    54 t be methods of a class that implements \Drupal\Core\Security\TrustedCallbackInterface or be an anonymous function. The callback was Drupal\Tests\Core\Render\RendererCallbackTest::renderCallback. See https://www.drupal.org/node/2966725',
                    58 t be methods of a class that implements \Drupal\Core\Security\TrustedCallbackInterface or be an anonymous function. The callback was \Drupal\Tests\Core\Render\callback. See https://www.drupal.org/node/2966725',
                    62 t be methods of a class that implements \Drupal\Core\Security\TrustedCallbackInterface or be an anonymous function. The callback was Drupal\Tests\Core\Render\RendererCallbackTest. See https://www.drupal.org/node/2966725',
            web/core/tests/Drupal/Tests/Core/Test  (2 usages found)
                TestDiscoveryTest.php  (2 usages found)
                    450 $data['simpletest-webtest'] = ['\Drupal\rest\Tests\NodeTest', FALSE];
                    461 $data['core-buildtest'] = ['\Drupal\BuildTests\Framework\Tests\BuildTestTest', 'Build'];