diff --git a/phpstan.neon b/phpstan.neon
index d7adbbd5..3a767e2d 100644
--- a/phpstan.neon
+++ b/phpstan.neon
@@ -4,7 +4,6 @@ includes:
 parameters:
 	ergebnis:
 		classesAllowedToBeExtended:
-			- Ergebnis\Classy\Test\Unit\Exception\AbstractTestCase
 			- InvalidArgumentException
 			- LogicException
 			- ParseError
diff --git a/test/Unit/Exception/AbstractTestCase.php b/test/Unit/Exception/AbstractTestCase.php
deleted file mode 100644
index 62f2f8f6..00000000
--- a/test/Unit/Exception/AbstractTestCase.php
+++ /dev/null
@@ -1,53 +0,0 @@
-<?php
-
-declare(strict_types=1);
-
-/**
- * Copyright (c) 2017 Andreas Möller
- *
- * For the full copyright and license information, please view
- * the LICENSE file that was distributed with this source code.
- *
- * @see https://github.com/ergebnis/classy
- */
-
-namespace Ergebnis\Classy\Test\Unit\Exception;
-
-use Ergebnis\Classy\Exception\ExceptionInterface;
-use Localheinz\Test\Util\Helper;
-use PHPUnit\Framework;
-
-/**
- * @internal
- */
-abstract class AbstractTestCase extends Framework\TestCase
-{
-    use Helper;
-
-    final public function testImplementsExceptionInterface(): void
-    {
-        $this->assertClassImplementsInterface(ExceptionInterface::class, $this->className());
-    }
-
-    final protected function className(): string
-    {
-        $className = \preg_replace(
-            '/Test$/',
-            '',
-            \str_replace(
-                'Ergebnis\\Classy\\Test\\Unit\\',
-                'Ergebnis\\Classy\\',
-                static::class
-            )
-        );
-
-        if (!\is_string($className)) {
-            throw new \RuntimeException(\sprintf(
-                'Could not resolve class name from test class name "%s".',
-                static::class
-            ));
-        }
-
-        return $className;
-    }
-}
diff --git a/test/Unit/Exception/DirectoryDoesNotExistTest.php b/test/Unit/Exception/DirectoryDoesNotExistTest.php
index f70cafb6..4ac88d1d 100644
--- a/test/Unit/Exception/DirectoryDoesNotExistTest.php
+++ b/test/Unit/Exception/DirectoryDoesNotExistTest.php
@@ -14,14 +14,19 @@
 namespace Ergebnis\Classy\Test\Unit\Exception;
 
 use Ergebnis\Classy\Exception\DirectoryDoesNotExist;
+use Ergebnis\Classy\Exception\ExceptionInterface;
+use Localheinz\Test\Util\Helper;
+use PHPUnit\Framework;
 
 /**
  * @internal
  *
  * @covers \Ergebnis\Classy\Exception\DirectoryDoesNotExist
  */
-final class DirectoryDoesNotExistTest extends AbstractTestCase
+final class DirectoryDoesNotExistTest extends Framework\TestCase
 {
+    use Helper;
+
     public function testFromDirectoryReturnsException(): void
     {
         $directory = $this->faker()->sentence;
@@ -29,6 +34,8 @@ public function testFromDirectoryReturnsException(): void
         $exception = DirectoryDoesNotExist::fromDirectory($directory);
 
         self::assertInstanceOf(DirectoryDoesNotExist::class, $exception);
+        self::assertInstanceOf(\InvalidArgumentException::class, $exception);
+        self::assertInstanceOf(ExceptionInterface::class, $exception);
 
         $message = \sprintf(
             'Directory "%s" does not exist.',
diff --git a/test/Unit/Exception/MultipleDefinitionsFoundTest.php b/test/Unit/Exception/MultipleDefinitionsFoundTest.php
index b98c44be..4f62141a 100644
--- a/test/Unit/Exception/MultipleDefinitionsFoundTest.php
+++ b/test/Unit/Exception/MultipleDefinitionsFoundTest.php
@@ -14,7 +14,10 @@
 namespace Ergebnis\Classy\Test\Unit\Exception;
 
 use Ergebnis\Classy\Construct;
+use Ergebnis\Classy\Exception\ExceptionInterface;
 use Ergebnis\Classy\Exception\MultipleDefinitionsFound;
+use Localheinz\Test\Util\Helper;
+use PHPUnit\Framework;
 
 /**
  * @internal
@@ -23,8 +26,10 @@
  *
  * @uses \Ergebnis\Classy\Construct
  */
-final class MultipleDefinitionsFoundTest extends AbstractTestCase
+final class MultipleDefinitionsFoundTest extends Framework\TestCase
 {
+    use Helper;
+
     public function testFromConstructsReturnsException(): void
     {
         $name = 'Foo\\Bar\\Baz';
@@ -41,6 +46,8 @@ public function testFromConstructsReturnsException(): void
         $exception = MultipleDefinitionsFound::fromConstructs($constructs);
 
         self::assertInstanceOf(MultipleDefinitionsFound::class, $exception);
+        self::assertInstanceOf(\RuntimeException::class, $exception);
+        self::assertInstanceOf(ExceptionInterface::class, $exception);
 
         $format = <<<'PHP'
 Multiple definitions have been found for the following constructs:
diff --git a/test/Unit/Exception/ParseErrorTest.php b/test/Unit/Exception/ParseErrorTest.php
index 1abe2980..ff91172d 100644
--- a/test/Unit/Exception/ParseErrorTest.php
+++ b/test/Unit/Exception/ParseErrorTest.php
@@ -13,19 +13,19 @@
 
 namespace Ergebnis\Classy\Test\Unit\Exception;
 
+use Ergebnis\Classy\Exception\ExceptionInterface;
 use Ergebnis\Classy\Exception\ParseError;
+use Localheinz\Test\Util\Helper;
+use PHPUnit\Framework;
 
 /**
  * @internal
  *
  * @covers \Ergebnis\Classy\Exception\ParseError
  */
-final class ParseErrorTest extends AbstractTestCase
+final class ParseErrorTest extends Framework\TestCase
 {
-    public function testExtendsParseError(): void
-    {
-        $this->assertClassExtends(\ParseError::class, ParseError::class);
-    }
+    use Helper;
 
     public function testFromParseErrorReturnsException(): void
     {
@@ -34,6 +34,8 @@ public function testFromParseErrorReturnsException(): void
         $exception = ParseError::fromParseError($parseError);
 
         self::assertInstanceOf(ParseError::class, $exception);
+        self::assertInstanceOf(\ParseError::class, $exception);
+        self::assertInstanceOf(ExceptionInterface::class, $exception);
         self::assertSame($parseError->getMessage(), $exception->getMessage());
         self::assertSame(0, $exception->getCode());
         self::assertSame($parseError, $exception->getPrevious());
@@ -50,6 +52,8 @@ public function testFromFileNameAndParseErrorReturnsException(): void
         );
 
         self::assertInstanceOf(ParseError::class, $exception);
+        self::assertInstanceOf(\ParseError::class, $exception);
+        self::assertInstanceOf(ExceptionInterface::class, $exception);
 
         $expectedMessage = \sprintf(
             'A parse error occurred when parsing "%s": "%s".',
diff --git a/test/Unit/Exception/ShouldNotHappenTest.php b/test/Unit/Exception/ShouldNotHappenTest.php
index ce021ab2..54469aef 100644
--- a/test/Unit/Exception/ShouldNotHappenTest.php
+++ b/test/Unit/Exception/ShouldNotHappenTest.php
@@ -13,25 +13,24 @@
 
 namespace Ergebnis\Classy\Test\Unit\Exception;
 
+use Ergebnis\Classy\Exception\ExceptionInterface;
 use Ergebnis\Classy\Exception\ShouldNotHappen;
+use PHPUnit\Framework;
 
 /**
  * @internal
  *
  * @covers \Ergebnis\Classy\Exception\ShouldNotHappen
  */
-final class ShouldNotHappenTest extends AbstractTestCase
+final class ShouldNotHappenTest extends Framework\TestCase
 {
-    public function testExtendsLogicException(): void
-    {
-        $this->assertClassExtends(\LogicException::class, ShouldNotHappen::class);
-    }
-
     public function testCreateReturnsException(): void
     {
         $exception = ShouldNotHappen::create();
 
         self::assertInstanceOf(ShouldNotHappen::class, $exception);
+        self::assertInstanceOf(\LogicException::class, $exception);
+        self::assertInstanceOf(ExceptionInterface::class, $exception);
         self::assertSame('This should not happen.', $exception->getMessage());
         self::assertSame(0, $exception->getCode());
         self::assertNull($exception->getPrevious());