diff --git a/core/phpstan-baseline.neon b/core/phpstan-baseline.neon
index 967e8324ef580dd5f2e3c3c9d1f2f30298e4ca06..af6f6c745d20eda127da778c6841f4a8054627b3 100644
--- a/core/phpstan-baseline.neon
+++ b/core/phpstan-baseline.neon
@@ -1644,68 +1644,3 @@ parameters:
 			message: "#^\\#pre_render callback '\\\\\\\\Drupal\\\\\\\\Tests\\\\\\\\Core…' at key '0' is not trusted\\.$#"
 			count: 1
 			path: tests/Drupal/Tests/Core/Render/RendererCallbackTest.php
-
-		-
-			message: "#^Call to an undefined method Drupal\\\\Tests\\\\Core\\\\Test\\\\TestClass\\:\\:assertArrayHasKey\\(\\)\\.$#"
-			count: 3
-			path: tests/Drupal/Tests/Core/Test/AssertContentTraitTest.php
-
-		-
-			message: "#^Call to an undefined method Drupal\\\\Tests\\\\Core\\\\Test\\\\TestClass\\:\\:assertDoesNotMatchRegularExpression\\(\\)\\.$#"
-			count: 1
-			path: tests/Drupal/Tests/Core/Test/AssertContentTraitTest.php
-
-		-
-			message: "#^Call to an undefined method Drupal\\\\Tests\\\\Core\\\\Test\\\\TestClass\\:\\:assertEmpty\\(\\)\\.$#"
-			count: 6
-			path: tests/Drupal/Tests/Core/Test/AssertContentTraitTest.php
-
-		-
-			message: "#^Call to an undefined method Drupal\\\\Tests\\\\Core\\\\Test\\\\TestClass\\:\\:assertEquals\\(\\)\\.$#"
-			count: 2
-			path: tests/Drupal/Tests/Core/Test/AssertContentTraitTest.php
-
-		-
-			message: "#^Call to an undefined method Drupal\\\\Tests\\\\Core\\\\Test\\\\TestClass\\:\\:assertMatchesRegularExpression\\(\\)\\.$#"
-			count: 2
-			path: tests/Drupal/Tests/Core/Test/AssertContentTraitTest.php
-
-		-
-			message: "#^Call to an undefined method Drupal\\\\Tests\\\\Core\\\\Test\\\\TestClass\\:\\:assertNotEmpty\\(\\)\\.$#"
-			count: 10
-			path: tests/Drupal/Tests/Core/Test/AssertContentTraitTest.php
-
-		-
-			message: "#^Call to an undefined method Drupal\\\\Tests\\\\Core\\\\Test\\\\TestClass\\:\\:assertNotEquals\\(\\)\\.$#"
-			count: 1
-			path: tests/Drupal/Tests/Core/Test/AssertContentTraitTest.php
-
-		-
-			message: "#^Call to an undefined method Drupal\\\\Tests\\\\Core\\\\Test\\\\TestClass\\:\\:assertNotFalse\\(\\)\\.$#"
-			count: 1
-			path: tests/Drupal/Tests/Core/Test/AssertContentTraitTest.php
-
-		-
-			message: "#^Call to an undefined method Drupal\\\\Tests\\\\Core\\\\Test\\\\TestClass\\:\\:assertSame\\(\\)\\.$#"
-			count: 1
-			path: tests/Drupal/Tests/Core/Test/AssertContentTraitTest.php
-
-		-
-			message: "#^Call to an undefined method Drupal\\\\Tests\\\\Core\\\\Test\\\\TestClass\\:\\:assertStringContainsString\\(\\)\\.$#"
-			count: 3
-			path: tests/Drupal/Tests/Core/Test/AssertContentTraitTest.php
-
-		-
-			message: "#^Call to an undefined method Drupal\\\\Tests\\\\Core\\\\Test\\\\TestClass\\:\\:assertStringNotContainsString\\(\\)\\.$#"
-			count: 3
-			path: tests/Drupal/Tests/Core/Test/AssertContentTraitTest.php
-
-		-
-			message: "#^Call to an undefined method Drupal\\\\Tests\\\\Core\\\\Test\\\\TestClass\\:\\:assertTrue\\(\\)\\.$#"
-			count: 6
-			path: tests/Drupal/Tests/Core/Test/AssertContentTraitTest.php
-
-		-
-			message: "#^Call to an undefined method Drupal\\\\Tests\\\\Core\\\\Test\\\\TestClass\\:\\:fail\\(\\)\\.$#"
-			count: 3
-			path: tests/Drupal/Tests/Core/Test/AssertContentTraitTest.php
diff --git a/core/tests/Drupal/Tests/Core/Test/AssertContentTraitTest.php b/core/tests/Drupal/Tests/Core/Test/AssertContentTraitTest.php
index 3bc362b328dadc623b247ec19327e6ab40ce258c..017b60712dea151f54970e5b14d2904e5caa8396 100644
--- a/core/tests/Drupal/Tests/Core/Test/AssertContentTraitTest.php
+++ b/core/tests/Drupal/Tests/Core/Test/AssertContentTraitTest.php
@@ -35,7 +35,7 @@ public function testGetTextContent() {
 
 }
 
-class TestClass {
+class TestClass extends UnitTestCase {
   use AssertContentTrait;
 
   public function _setRawContent($content) {