diff --git a/tests/controller/controller_test.php b/tests/controller/controller_test.php
index ddc1921b0e..37df094d40 100644
--- a/tests/controller/controller_test.php
+++ b/tests/controller/controller_test.php
@@ -107,7 +107,10 @@ class phpbb_controller_controller_test extends phpbb_test_case
 			array(new foo\controller(), array(), array()),
 			array(array(new foo\controller(), 'handle_fail'), array(), array(), '\phpbb\controller\exception', 'CONTROLLER_ARGUMENT_VALUE_MISSING'),
 			array('', array(), array(), '\ReflectionException', 'Function () does not exist'),
-			array(new phpbb\controller\foo, array(), array(), '\ReflectionException', 'Method __invoke does not exist'),
+			// Before PHP 8: 'Method __invoke does not exist'
+			// As of PHP 8: 'Method phpbb\controller\foo::__invoke() does not exist'
+			array(new phpbb\controller\foo, array(), array(), '\ReflectionException', 
+				'Method ' . (version_compare(PHP_VERSION, '8', '>=') ? 'phpbb\controller\foo::__invoke()' : '__invoke') . ' does not exist'),
 		);
 	}
 
diff --git a/tests/functional/feed_test.php b/tests/functional/feed_test.php
index 9dde6ffcb0..2f3ae4e39a 100644
--- a/tests/functional/feed_test.php
+++ b/tests/functional/feed_test.php
@@ -30,7 +30,9 @@ class phpbb_functional_feed_test extends phpbb_functional_test_case
 	{
 		parent::__construct($name, $data, $dataName);
 
-		$this->backupStaticAttributesBlacklist['phpbb_functional_feed_test'] = array('init_values');
+		$this->excludeBackupStaticAttributes([
+			'phpbb_functional_feed_test' => ['init_values'],
+		]);
 
 		$this->purge_cache();
 	}
diff --git a/tests/functional/ucp_allow_pm_test.php b/tests/functional/ucp_allow_pm_test.php
index 2d41296ddf..01418b25b1 100644
--- a/tests/functional/ucp_allow_pm_test.php
+++ b/tests/functional/ucp_allow_pm_test.php
@@ -22,9 +22,9 @@ class phpbb_functional_ucp_allow_pm_test extends phpbb_functional_test_case
 	{
 		parent::__construct();
 
-		$this->backupStaticAttributesBlacklist += array(
-			'phpbb_functional_ucp_allow_pm_test' => array('data'),
-		);
+		$this->excludeBackupStaticAttributes([
+			'phpbb_functional_ucp_allow_pm_test' => ['data'],
+		]);
 	}
 
 	// user A sends a PM to user B where B accepts PM
diff --git a/tests/test_framework/phpbb_database_test_case.php b/tests/test_framework/phpbb_database_test_case.php
index 04324e0df1..ecfc948793 100644
--- a/tests/test_framework/phpbb_database_test_case.php
+++ b/tests/test_framework/phpbb_database_test_case.php
@@ -29,21 +29,35 @@ abstract class phpbb_database_test_case extends TestCase
 
 	static protected $install_schema_file;
 
-	public function __construct($name = NULL, array $data = array(), $dataName = '')
+	static protected $phpunit_version; 
+
+	public function __construct($name = NULL, array $data = [], $dataName = '')
 	{
 		parent::__construct($name, $data, $dataName);
-		$this->backupStaticAttributesBlacklist += array(
-			'SebastianBergmann\CodeCoverage\CodeCoverage' => array('instance'),
-			'SebastianBergmann\CodeCoverage\Filter' => array('instance'),
-			'SebastianBergmann\CodeCoverage\Util' => array('ignoredLines', 'templateMethods'),
-			'SebastianBergmann\Timer\Timer' => array('startTimes',),
-			'PHP_Token_Stream' => array('customTokens'),
-			'PHP_Token_Stream_CachingFactory' => array('cache'),
 
-			'phpbb_database_test_case' => array('already_connected'),
-		);
+		self::$phpunit_version = PHPUnit\Runner\Version::id();
 
-		$this->db_connections = array();
+		$backupStaticAttributesBlacklist = [
+			'SebastianBergmann\CodeCoverage\CodeCoverage' => ['instance'],
+			'SebastianBergmann\CodeCoverage\Filter' => ['instance'],
+			'SebastianBergmann\CodeCoverage\Util' => ['ignoredLines', 'templateMethods'],
+			'SebastianBergmann\Timer\Timer' => ['startTimes'],
+			'PHP_Token_Stream' => ['customTokens'],
+			'PHP_Token_Stream_CachingFactory' => ['cache'],
+
+			'phpbb_database_test_case' => ['already_connected'],
+		];
+
+		if (version_compare(self::$phpunit_version, '9.0', '>='))
+		{
+			$this->backupStaticAttributesExcludeList += $backupStaticAttributesBlacklist;
+		}
+		else
+		{
+			$this->backupStaticAttributesBlacklist += $backupStaticAttributesBlacklist;
+		}
+
+		$this->db_connections = [];
 	}
 
 	/**
@@ -353,4 +367,56 @@ abstract class phpbb_database_test_case extends TestCase
 			$this->assertTrue(true);
 		}
 	}
+
+	/**
+	 * PHPUnit deprecates several methods and properties in its recent versions
+	 * Provide BC layer to be able to test in multiple environment settings
+	 */
+    public function expectException(string $exception): void
+    {
+		if (version_compare(self::$phpunit_version, '9.0', '>='))
+		{
+			switch ($exception) {
+				case PHPUnit\Framework\Error\Deprecated::class:
+					parent::expectDeprecation();
+				break;
+
+				case PHPUnit\Framework\Error\Error::class:
+					parent::expectError();
+				break;
+
+				case PHPUnit\Framework\Error\Notice::class:
+					parent::expectNotice();
+				break;
+
+				case PHPUnit\Framework\Error\Warning::class:
+					parent::expectWarning();
+				break;
+
+				default:
+					parent::expectException($exception);
+				break;
+			}
+		}
+		else
+		{
+			parent::expectException($exception);
+		}
+	}
+
+	/**
+	 * PHPUnit deprecates several methods and properties in its recent versions
+	 * Provide BC layer to be able to test in multiple environment settings
+	 */
+    public static function assertFileNotExists(string $filename, string $message = ''): void
+    {
+		if (version_compare(self::$phpunit_version, '9.0', '>='))
+		{
+			parent::assertFileDoesNotExist($filename, $message);
+		}
+		else
+		{
+			parent::assertFileNotExists($filename, $message);
+		}
+	}
 }
diff --git a/tests/test_framework/phpbb_functional_test_case.php b/tests/test_framework/phpbb_functional_test_case.php
index 10e444dee5..f21e49b65b 100644
--- a/tests/test_framework/phpbb_functional_test_case.php
+++ b/tests/test_framework/phpbb_functional_test_case.php
@@ -183,13 +183,14 @@ class phpbb_functional_test_case extends phpbb_test_case
 	{
 	}
 
-	public function __construct($name = NULL, array $data = array(), $dataName = '')
+	public function __construct($name = NULL, array $data = [], $dataName = '')
 	{
 		parent::__construct($name, $data, $dataName);
 
-		$this->backupStaticAttributesBlacklist += array(
-			'phpbb_functional_test_case' => array('config', 'already_installed'),
-		);
+		$backupStaticAttributesBlacklist = [
+			'phpbb_functional_test_case' => ['config', 'already_installed'],
+		];
+		$this->excludeBackupStaticAttributes($backupStaticAttributesBlacklist);
 	}
 
 	protected function get_db()
diff --git a/tests/test_framework/phpbb_test_case.php b/tests/test_framework/phpbb_test_case.php
index 8e09f17ede..cb48de23d4 100644
--- a/tests/test_framework/phpbb_test_case.php
+++ b/tests/test_framework/phpbb_test_case.php
@@ -16,20 +16,25 @@ use PHPUnit\Framework\TestCase;
 class phpbb_test_case extends TestCase
 {
 	protected $test_case_helpers;
+	static protected $phpunit_version; 
 
 	public function __construct($name = NULL, array $data = array(), $dataName = '')
 	{
 		parent::__construct($name, $data, $dataName);
-		$this->backupStaticAttributesBlacklist += array(
-			'SebastianBergmann\CodeCoverage\CodeCoverage' => array('instance'),
-			'SebastianBergmann\CodeCoverage\Filter' => array('instance'),
-			'SebastianBergmann\CodeCoverage\Util' => array('ignoredLines', 'templateMethods'),
-			'SebastianBergmann\Timer\Timer' => array('startTimes',),
-			'PHP_Token_Stream' => array('customTokens'),
-			'PHP_Token_Stream_CachingFactory' => array('cache'),
 
-			'phpbb_database_test_case' => array('already_connected', 'last_post_timestamp'),
-		);
+		self::$phpunit_version = PHPUnit\Runner\Version::id();
+
+		$backupStaticAttributesBlacklist = [
+			'SebastianBergmann\CodeCoverage\CodeCoverage' => ['instance'],
+			'SebastianBergmann\CodeCoverage\Filter' => ['instance'],
+			'SebastianBergmann\CodeCoverage\Util' => ['ignoredLines', 'templateMethods'],
+			'SebastianBergmann\Timer\Timer' => ['startTimes'],
+			'PHP_Token_Stream' => ['customTokens'],
+			'PHP_Token_Stream_CachingFactory' => ['cache'],
+
+			'phpbb_database_test_case' => ['already_connected', 'last_post_timestamp'],
+		];
+		$this->excludeBackupStaticAttributes($backupStaticAttributesBlacklist);
 	}
 
 	public function get_test_case_helpers()
@@ -46,4 +51,88 @@ class phpbb_test_case extends TestCase
 	{
 		$this->get_test_case_helpers()->setExpectedTriggerError($errno, $message);
 	}
+
+	/**
+	 * PHPUnit deprecates several methods and properties in its recent versions
+	 * Provide BC layer to be able to test in multiple environment settings
+	 */
+	public function excludeBackupStaticAttributes($attributes_array)
+	{
+		if (version_compare(self::$phpunit_version, '9.0', '>='))
+		{
+			$this->backupStaticAttributesExcludeList += $attributes_array;
+		}
+		else
+		{
+			$this->backupStaticAttributesBlacklist += $attributes_array;
+		}
+	}
+
+	/**
+	 * PHPUnit deprecates several methods and properties in its recent versions
+	 * Provide BC layer to be able to test in multiple environment settings
+	 */
+	public static function assertRegExp(string $pattern, string $string, string $message = ''): void
+	{
+		if (version_compare(self::$phpunit_version, '9.0', '>='))
+		{
+			parent::assertMatchesRegularExpression($pattern, $string, $message);
+		}
+		else
+		{
+			parent::assertRegExp($pattern, $string, $message);
+		}
+	}
+
+	/**
+	 * PHPUnit deprecates several methods and properties in its recent versions
+	 * Provide BC layer to be able to test in multiple environment settings
+	 */
+    public function expectException(string $exception): void
+    {
+		if (version_compare(self::$phpunit_version, '9.0', '>='))
+		{
+			switch ($exception) {
+				case PHPUnit\Framework\Error\Deprecated::class:
+					parent::expectDeprecation();
+				break;
+
+				case PHPUnit\Framework\Error\Error::class:
+					parent::expectError();
+				break;
+
+				case PHPUnit\Framework\Error\Notice::class:
+					parent::expectNotice();
+				break;
+
+				case PHPUnit\Framework\Error\Warning::class:
+					parent::expectWarning();
+				break;
+
+				default:
+					parent::expectException($exception);
+				break;
+			}
+		}
+		else
+		{
+			parent::expectException($exception);
+		}
+	}
+
+	/**
+	 * PHPUnit deprecates several methods and properties in its recent versions
+	 * Provide BC layer to be able to test in multiple environment settings
+	 */
+    public static function assertFileNotExists(string $filename, string $message = ''): void
+    {
+		if (version_compare(self::$phpunit_version, '9.0', '>='))
+		{
+			parent::assertFileDoesNotExist($filename, $message);
+		}
+		else
+		{
+			parent::assertFileNotExists($filename, $message);
+		}
+	}
 }