diff --git a/core/modules/serialization/tests/src/Unit/Normalizer/EntityNormalizerTest.php b/core/modules/serialization/tests/src/Unit/Normalizer/EntityNormalizerTest.php
index f195da6..bbddbdd 100644
--- a/core/modules/serialization/tests/src/Unit/Normalizer/EntityNormalizerTest.php
+++ b/core/modules/serialization/tests/src/Unit/Normalizer/EntityNormalizerTest.php
@@ -287,7 +287,7 @@ public function testDenormalizeWithInvalidBundle() {
       ->will($this->returnValue($entity_type_storage));
 
     $this->setExpectedException(UnexpectedValueException::class);
-    $this->assertNotNull($this->entityNormalizer->denormalize($test_data, 'Drupal\Core\Entity\ContentEntityBase', NULL, ['entity_type' => 'test']));
+    $this->entityNormalizer->denormalize($test_data, 'Drupal\Core\Entity\ContentEntityBase', NULL, ['entity_type' => 'test']);
   }
 
   /**
diff --git a/core/tests/Drupal/Tests/Component/Plugin/Discovery/DiscoveryTraitTest.php b/core/tests/Drupal/Tests/Component/Plugin/Discovery/DiscoveryTraitTest.php
index 04268d2..b0f58c9 100644
--- a/core/tests/Drupal/Tests/Component/Plugin/Discovery/DiscoveryTraitTest.php
+++ b/core/tests/Drupal/Tests/Component/Plugin/Discovery/DiscoveryTraitTest.php
@@ -70,10 +70,7 @@ public function testDoGetDefinitionException($expected, $definitions, $plugin_id
     $method_ref->setAccessible(TRUE);
     // Call doGetDefinition, with $exception_on_invalid always TRUE.
     $this->setExpectedException(PluginNotFoundException::class);
-    $this->assertSame(
-      $expected,
-      $method_ref->invoke($trait, $definitions, $plugin_id, TRUE)
-    );
+    $method_ref->invoke($trait, $definitions, $plugin_id, TRUE);
   }
 
   /**
@@ -110,10 +107,7 @@ public function testGetDefinitionException($expected, $definitions, $plugin_id)
       ->willReturn($definitions);
     // Call getDefinition(), with $exception_on_invalid always TRUE.
     $this->setExpectedException(PluginNotFoundException::class);
-    $this->assertSame(
-      $expected,
-      $trait->getDefinition($plugin_id, TRUE)
-    );
+    $trait->getDefinition($plugin_id, TRUE);
   }
 
   /**
diff --git a/core/tests/Drupal/Tests/Component/Utility/ArgumentsResolverTest.php b/core/tests/Drupal/Tests/Component/Utility/ArgumentsResolverTest.php
index 4dbc8a7..1710609 100644
--- a/core/tests/Drupal/Tests/Component/Utility/ArgumentsResolverTest.php
+++ b/core/tests/Drupal/Tests/Component/Utility/ArgumentsResolverTest.php
@@ -129,8 +129,7 @@ public function testGetWildcardArgumentNoTypehint() {
 
     $callable = function($route) {};
     $this->setExpectedException(\RuntimeException::class, 'requires a value for the "$route" argument.');
-    $arguments = $resolver->getArguments($callable);
-    $this->assertNull($arguments);
+    $resolver->getArguments($callable);
   }
 
   /**
@@ -158,8 +157,7 @@ public function testHandleNotUpcastedArgument() {
 
     $callable = function(\stdClass $foo) {};
     $this->setExpectedException(\RuntimeException::class, 'requires a value for the "$foo" argument.');
-    $arguments = $resolver->getArguments($callable);
-    $this->assertNull($arguments);
+    $resolver->getArguments($callable);
   }
 
   /**
@@ -170,8 +168,7 @@ public function testHandleNotUpcastedArgument() {
   public function testHandleUnresolvedArgument($callable) {
     $resolver = new ArgumentsResolver([], [], []);
     $this->setExpectedException(\RuntimeException::class, 'requires a value for the "$foo" argument.');
-    $arguments = $resolver->getArguments($callable);
-    $this->assertNull($arguments);
+    $resolver->getArguments($callable);
   }
 
   /**
diff --git a/core/tests/Drupal/Tests/Core/Entity/BaseFieldDefinitionTest.php b/core/tests/Drupal/Tests/Core/Entity/BaseFieldDefinitionTest.php
index 3a7b3c1..341ed9c 100644
--- a/core/tests/Drupal/Tests/Core/Entity/BaseFieldDefinitionTest.php
+++ b/core/tests/Drupal/Tests/Core/Entity/BaseFieldDefinitionTest.php
@@ -318,9 +318,7 @@ public function testInvalidDefaultValueCallback() {
     $definition = BaseFieldDefinition::create($this->fieldType);
     // setDefaultValueCallback returns $this.
     $this->setExpectedException(\InvalidArgumentException::class);
-    $this->assertSame($definition,
-      $definition->setDefaultValueCallback([get_class($this), 'mockDefaultValueCallback'])
-    );
+    $definition->setDefaultValueCallback([get_class($this), 'mockDefaultValueCallback']);
   }
 
   /**
diff --git a/core/tests/Drupal/Tests/Core/Form/FormAjaxResponseBuilderTest.php b/core/tests/Drupal/Tests/Core/Form/FormAjaxResponseBuilderTest.php
index ce627359..177504c 100644
--- a/core/tests/Drupal/Tests/Core/Form/FormAjaxResponseBuilderTest.php
+++ b/core/tests/Drupal/Tests/Core/Form/FormAjaxResponseBuilderTest.php
@@ -56,7 +56,7 @@ public function testBuildResponseNoTriggeringElement() {
 
     $expected = [];
     $this->setExpectedException(HttpException::class);
-    $this->assertSame($expected, $this->formAjaxResponseBuilder->buildResponse($request, $form, $form_state, $commands));
+    $this->formAjaxResponseBuilder->buildResponse($request, $form, $form_state, $commands);
   }
 
   /**
@@ -75,7 +75,7 @@ public function testBuildResponseNoCallable() {
 
     $expected = [];
     $this->setExpectedException(HttpException::class);
-    $this->assertSame($expected, $this->formAjaxResponseBuilder->buildResponse($request, $form, $form_state, $commands));
+    $this->formAjaxResponseBuilder->buildResponse($request, $form, $form_state, $commands);
   }
 
   /**
diff --git a/core/tests/Drupal/Tests/Core/PageCache/ChainResponsePolicyTest.php b/core/tests/Drupal/Tests/Core/PageCache/ChainResponsePolicyTest.php
index 902d646..8de3a5c 100644
--- a/core/tests/Drupal/Tests/Core/PageCache/ChainResponsePolicyTest.php
+++ b/core/tests/Drupal/Tests/Core/PageCache/ChainResponsePolicyTest.php
@@ -85,8 +85,7 @@ public function testChainExceptionOnInvalidReturnValue($return_value) {
     $this->policy->addPolicy($rule);
 
     $this->setExpectedException(\UnexpectedValueException::class);
-    $actual_result = $this->policy->check($this->response, $this->request);
-    $this->assertSame(NULL, $actual_result);
+    $this->policy->check($this->response, $this->request);
   }
 
   /**
diff --git a/core/tests/Drupal/Tests/Core/Plugin/Context/ContextDefinitionTest.php b/core/tests/Drupal/Tests/Core/Plugin/Context/ContextDefinitionTest.php
index 58f61d1..6eda2e3 100644
--- a/core/tests/Drupal/Tests/Core/Plugin/Context/ContextDefinitionTest.php
+++ b/core/tests/Drupal/Tests/Core/Plugin/Context/ContextDefinitionTest.php
@@ -155,10 +155,7 @@ public function testGetDataDefinitionInvalidType($is_multiple) {
       ->willReturn($data_type);
 
     $this->setExpectedException(\Exception::class);
-    $this->assertSame(
-      $mock_data_definition,
-      $mock_context_definition->getDataDefinition()
-    );
+    $mock_context_definition->getDataDefinition();
   }
 
   /**
diff --git a/core/tests/Drupal/Tests/Core/UnroutedUrlTest.php b/core/tests/Drupal/Tests/Core/UnroutedUrlTest.php
index 7afd0bb..680e2fd 100644
--- a/core/tests/Drupal/Tests/Core/UnroutedUrlTest.php
+++ b/core/tests/Drupal/Tests/Core/UnroutedUrlTest.php
@@ -143,7 +143,7 @@ public function testCreateFromRequest() {
       ->will($this->throwException(new ResourceNotFoundException()));
 
     $this->setExpectedException(ResourceNotFoundException::class);
-    $this->assertNull(Url::createFromRequest($request));
+    Url::createFromRequest($request);
   }
 
   /**
@@ -211,7 +211,7 @@ public function testGetRouteParameters($uri) {
   public function testGetInternalPath($uri) {
     $url = Url::fromUri($uri);
     $this->setExpectedException(\Exception::class);
-    $this->assertNull($url->getInternalPath());
+    $url->getInternalPath();
   }
 
   /**
diff --git a/core/tests/Drupal/Tests/Core/UrlTest.php b/core/tests/Drupal/Tests/Core/UrlTest.php
index d60a58c..b2e0976 100644
--- a/core/tests/Drupal/Tests/Core/UrlTest.php
+++ b/core/tests/Drupal/Tests/Core/UrlTest.php
@@ -290,7 +290,7 @@ public function testUrlFromRequestInvalid() {
       ->will($this->throwException(new ResourceNotFoundException()));
 
     $this->setExpectedException(ResourceNotFoundException::class);
-    $this->assertNull(Url::createFromRequest($request));
+    Url::createFromRequest($request);
   }
 
   /**