diff --git a/tests/_files/AbstractTest.php b/tests/_files/abstract/with-test-suffix/AbstractTest.php
similarity index 100%
rename from tests/_files/AbstractTest.php
rename to tests/_files/abstract/with-test-suffix/AbstractTest.php
diff --git a/tests/_files/abstract/with-test-suffix/ConcreteTestClassExtendingAbstractTestClassWithTestSuffixTest.php b/tests/_files/abstract/with-test-suffix/ConcreteTestClassExtendingAbstractTestClassWithTestSuffixTest.php
new file mode 100644
index 00000000000..f7cf69ad134
--- /dev/null
+++ b/tests/_files/abstract/with-test-suffix/ConcreteTestClassExtendingAbstractTestClassWithTestSuffixTest.php
@@ -0,0 +1,14 @@
+<?php declare(strict_types=1);
+/*
+ * This file is part of PHPUnit.
+ *
+ * (c) Sebastian Bergmann <sebastian@phpunit.de>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+namespace PHPUnit\TestFixture;
+
+final class ConcreteTestClassExtendingAbstractTestClassWithTestSuffixTest extends AbstractTest
+{
+}
diff --git a/tests/_files/AbstractTestCase.php b/tests/_files/abstract/without-test-suffix/AbstractTestCase.php
similarity index 100%
rename from tests/_files/AbstractTestCase.php
rename to tests/_files/abstract/without-test-suffix/AbstractTestCase.php
diff --git a/tests/_files/abstract/without-test-suffix/ConcreteTestClassExtendingAbstractTestClassWithoutTestSuffixTest.php b/tests/_files/abstract/without-test-suffix/ConcreteTestClassExtendingAbstractTestClassWithoutTestSuffixTest.php
new file mode 100644
index 00000000000..528d679382f
--- /dev/null
+++ b/tests/_files/abstract/without-test-suffix/ConcreteTestClassExtendingAbstractTestClassWithoutTestSuffixTest.php
@@ -0,0 +1,14 @@
+<?php declare(strict_types=1);
+/*
+ * This file is part of PHPUnit.
+ *
+ * (c) Sebastian Bergmann <sebastian@phpunit.de>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+namespace PHPUnit\TestFixture;
+
+final class ConcreteTestClassExtendingAbstractTestClassWithoutTestSuffixTest extends AbstractTestCase
+{
+}
diff --git a/tests/end-to-end/generic/abstract-test-class-with-test-suffix.phpt b/tests/end-to-end/generic/abstract-test-class/abstract-test-class-with-test-suffix.phpt
similarity index 56%
rename from tests/end-to-end/generic/abstract-test-class-with-test-suffix.phpt
rename to tests/end-to-end/generic/abstract-test-class/abstract-test-class-with-test-suffix.phpt
index 5d6479c9ee5..6b21c90bd42 100644
--- a/tests/end-to-end/generic/abstract-test-class-with-test-suffix.phpt
+++ b/tests/end-to-end/generic/abstract-test-class/abstract-test-class-with-test-suffix.phpt
@@ -1,12 +1,12 @@
 --TEST--
-phpunit ../../_files/AbstractTest.php
+phpunit ../../../_files/abstract/with-test-suffix/AbstractTest.php
 --FILE--
 <?php declare(strict_types=1);
 $_SERVER['argv'][] = '--do-not-cache-result';
 $_SERVER['argv'][] = '--no-configuration';
-$_SERVER['argv'][] = __DIR__ . '/../../_files/AbstractTest.php';
+$_SERVER['argv'][] = __DIR__ . '/../../../_files/abstract/with-test-suffix/AbstractTest.php';
 
-require_once __DIR__ . '/../../bootstrap.php';
+require_once __DIR__ . '/../../../bootstrap.php';
 PHPUnit\TextUI\Application::main();
 --EXPECTF--
 Class PHPUnit\TestFixture\AbstractTest declared in %sAbstractTest.php is abstract
diff --git a/tests/end-to-end/generic/abstract-test-class-without-test-suffix.phpt b/tests/end-to-end/generic/abstract-test-class/abstract-test-class-without-test-suffix.phpt
similarity index 55%
rename from tests/end-to-end/generic/abstract-test-class-without-test-suffix.phpt
rename to tests/end-to-end/generic/abstract-test-class/abstract-test-class-without-test-suffix.phpt
index 55b1a229f1a..aa1d000719b 100644
--- a/tests/end-to-end/generic/abstract-test-class-without-test-suffix.phpt
+++ b/tests/end-to-end/generic/abstract-test-class/abstract-test-class-without-test-suffix.phpt
@@ -1,12 +1,12 @@
 --TEST--
-phpunit ../../_files/AbstractTestCase.php
+phpunit ../../../_files/abstract/without-test-suffix/AbstractTestCase.php
 --FILE--
 <?php declare(strict_types=1);
 $_SERVER['argv'][] = '--do-not-cache-result';
 $_SERVER['argv'][] = '--no-configuration';
-$_SERVER['argv'][] = __DIR__ . '/../../_files/AbstractTestCase.php';
+$_SERVER['argv'][] = __DIR__ . '/../../../_files/abstract/without-test-suffix/AbstractTestCase.php';
 
-require_once __DIR__ . '/../../bootstrap.php';
+require_once __DIR__ . '/../../../bootstrap.php';
 PHPUnit\TextUI\Application::main();
 --EXPECTF--
 Class PHPUnit\TestFixture\AbstractTestCase declared in %sAbstractTestCase.php is abstract
diff --git a/tests/end-to-end/generic/abstract-test-class/concrete-test-class-extending-abstract-test-class-with-test-suffix.phpt b/tests/end-to-end/generic/abstract-test-class/concrete-test-class-extending-abstract-test-class-with-test-suffix.phpt
new file mode 100644
index 00000000000..291950036ba
--- /dev/null
+++ b/tests/end-to-end/generic/abstract-test-class/concrete-test-class-extending-abstract-test-class-with-test-suffix.phpt
@@ -0,0 +1,20 @@
+--TEST--
+phpunit ../../../_files/abstract/with-test-suffix/ConcreteTestClassExtendingAbstractTestClassWithTestSuffixTest.php
+--FILE--
+<?php declare(strict_types=1);
+$_SERVER['argv'][] = '--do-not-cache-result';
+$_SERVER['argv'][] = '--no-configuration';
+$_SERVER['argv'][] = __DIR__ . '/../../../_files/abstract/with-test-suffix/ConcreteTestClassExtendingAbstractTestClassWithTestSuffixTest.php';
+
+require_once __DIR__ . '/../../../bootstrap.php';
+PHPUnit\TextUI\Application::main();
+--EXPECTF--
+PHPUnit %s by Sebastian Bergmann and contributors.
+
+Runtime: %s
+
+.                                                                   1 / 1 (100%)
+
+Time: %s, Memory: %s
+
+OK (1 test, 1 assertion)
diff --git a/tests/end-to-end/generic/abstract-test-class/concrete-test-class-extending-abstract-test-class-without-test-suffix.phpt b/tests/end-to-end/generic/abstract-test-class/concrete-test-class-extending-abstract-test-class-without-test-suffix.phpt
new file mode 100644
index 00000000000..698e6daa7dd
--- /dev/null
+++ b/tests/end-to-end/generic/abstract-test-class/concrete-test-class-extending-abstract-test-class-without-test-suffix.phpt
@@ -0,0 +1,14 @@
+--TEST--
+phpunit ../../../_files/abstract/without-test-suffix/ConcreteTestClassExtendingAbstractTestClassWithoutTestSuffixTest.php
+--SKIPIF--
+<?php declare(strict_types=1);
+print 'skip: https://github.com/sebastianbergmann/phpunit/issues/4979';
+--FILE--
+<?php declare(strict_types=1);
+$_SERVER['argv'][] = '--do-not-cache-result';
+$_SERVER['argv'][] = '--no-configuration';
+$_SERVER['argv'][] = __DIR__ . '/../../../_files/abstract/without-test-suffix/ConcreteTestClassExtendingAbstractTestClassWithoutTestSuffixTest.php';
+
+require_once __DIR__ . '/../../../bootstrap.php';
+PHPUnit\TextUI\Application::main();
+--EXPECTF--
diff --git a/tests/end-to-end/generic/abstract-test-class/directory-with-concrete-test-class-and-abstract-test-class-with-test-suffix.phpt b/tests/end-to-end/generic/abstract-test-class/directory-with-concrete-test-class-and-abstract-test-class-with-test-suffix.phpt
new file mode 100644
index 00000000000..b952cfb5721
--- /dev/null
+++ b/tests/end-to-end/generic/abstract-test-class/directory-with-concrete-test-class-and-abstract-test-class-with-test-suffix.phpt
@@ -0,0 +1,14 @@
+--TEST--
+phpunit ../../../_files/abstract/with-test-suffix
+--SKIPIF--
+<?php declare(strict_types=1);
+print 'skip: https://github.com/sebastianbergmann/phpunit/issues/4979';
+--FILE--
+<?php declare(strict_types=1);
+$_SERVER['argv'][] = '--do-not-cache-result';
+$_SERVER['argv'][] = '--no-configuration';
+$_SERVER['argv'][] = __DIR__ . '/../../../_files/abstract/with-test-suffix';
+
+require_once __DIR__ . '/../../../bootstrap.php';
+PHPUnit\TextUI\Application::main();
+--EXPECTF--
diff --git a/tests/end-to-end/generic/abstract-test-class/directory-with-concrete-test-class-and-abstract-test-class-without-test-suffix.phpt b/tests/end-to-end/generic/abstract-test-class/directory-with-concrete-test-class-and-abstract-test-class-without-test-suffix.phpt
new file mode 100644
index 00000000000..e76626eb99c
--- /dev/null
+++ b/tests/end-to-end/generic/abstract-test-class/directory-with-concrete-test-class-and-abstract-test-class-without-test-suffix.phpt
@@ -0,0 +1,20 @@
+--TEST--
+phpunit ../../../_files/abstract/without-test-suffix
+--FILE--
+<?php declare(strict_types=1);
+$_SERVER['argv'][] = '--do-not-cache-result';
+$_SERVER['argv'][] = '--no-configuration';
+$_SERVER['argv'][] = __DIR__ . '/../../../_files/abstract/without-test-suffix';
+
+require_once __DIR__ . '/../../../bootstrap.php';
+PHPUnit\TextUI\Application::main();
+--EXPECTF--
+PHPUnit %s by Sebastian Bergmann and contributors.
+
+Runtime: %s
+
+.                                                                   1 / 1 (100%)
+
+Time: %s, Memory: %s
+
+OK (1 test, 1 assertion)
diff --git a/tests/end-to-end/generic/concrete-test-class.phpt b/tests/end-to-end/generic/concrete-test-class.phpt
deleted file mode 100644
index 830e0bc854c..00000000000
--- a/tests/end-to-end/generic/concrete-test-class.phpt
+++ /dev/null
@@ -1,20 +0,0 @@
---TEST--
-phpunit ../../_files/ConcreteTest.php
---FILE--
-<?php declare(strict_types=1);
-$_SERVER['argv'][] = '--do-not-cache-result';
-$_SERVER['argv'][] = '--no-configuration';
-$_SERVER['argv'][] = __DIR__ . '/../../_files/ConcreteTest.php';
-
-require_once __DIR__ . '/../../bootstrap.php';
-PHPUnit\TextUI\Application::main();
---EXPECTF--
-PHPUnit %s by Sebastian Bergmann and contributors.
-
-Runtime: %s
-
-..                                                                  2 / 2 (100%)
-
-Time: %s, Memory: %s
-
-OK (2 tests, 2 assertions)