diff --git a/maintenance/MathGenerateTests.php b/maintenance/MathGenerateTests.php
index d9a524c..bcd4852 100644
--- a/maintenance/MathGenerateTests.php
+++ b/maintenance/MathGenerateTests.php
@@ -94,5 +94,5 @@ class MathGenerateTests extends Maintenance {
 	}
 }
 
-$maintClass = 'MathGenerateTests';
+$maintClass = MathGenerateTests::class;
 require_once RUN_MAINTENANCE_IF_MAIN;
diff --git a/src/MathHooks.php b/src/MathHooks.php
index cc050f7..e5c5fda 100644
--- a/src/MathHooks.php
+++ b/src/MathHooks.php
@@ -171,10 +171,10 @@ class MathHooks {
 	 * @return bool true
 	 */
 	static function onParserFirstCallInit( $parser ) {
-		$parser->setHook( 'math', [ 'MathHooks', 'mathTagHook' ] );
+		$parser->setHook( 'math', [ self::class, 'mathTagHook' ] );
 		// @deprecated the ce tag is deprecated in favour of chem cf. T153606
-		$parser->setHook( 'ce', [ 'MathHooks', 'chemTagHook' ] );
-		$parser->setHook( 'chem', [ 'MathHooks', 'chemTagHook' ] );
+		$parser->setHook( 'ce', [ self::class, 'chemTagHook' ] );
+		$parser->setHook( 'chem', [ self::class, 'chemTagHook' ] );
 
 		return true;
 	}
@@ -373,7 +373,7 @@ class MathHooks {
 			MathMathML::batchEvaluate( self::$tags );
 		}
 		foreach ( self::$tags as $key => $tag ) {
-			$value = call_user_func_array( [ "MathHooks", "mathPostTagHook" ], $tag );
+			$value = call_user_func_array( [ self::class, 'mathPostTagHook' ], $tag );
 			// Workaround for https://phabricator.wikimedia.org/T103269
 			$text = preg_replace( '/(<mw:editsection[^>]*>.*?)' . preg_quote( $key ) .
 				'(.*?)<\/mw:editsection>/',
diff --git a/tests/phpunit/MathInputCheckTest.php b/tests/phpunit/MathInputCheckTest.php
index dc7aeef..1a7302a 100644
--- a/tests/phpunit/MathInputCheckTest.php
+++ b/tests/phpunit/MathInputCheckTest.php
@@ -12,7 +12,7 @@ class MathInputCheckTest extends MediaWikiTestCase {
 	 * @covers MathInputCheck::isValid
 	 */
 	public function testIsValid() {
-		$InputCheck = $this->getMockBuilder( 'MathInputCheck' )->getMock();
+		$InputCheck = $this->getMockBuilder( MathInputCheck::class )->getMock();
 		$this->assertEquals( $InputCheck->IsValid(), false );
 	}
 
@@ -21,7 +21,7 @@ class MathInputCheckTest extends MediaWikiTestCase {
 	 * @todo   Implement testGetError().
 	 */
 	public function testGetError() {
-		$InputCheck = $this->getMockBuilder( 'MathInputCheck' )->getMock();
+		$InputCheck = $this->getMockBuilder( MathInputCheck::class )->getMock();
 		$this->assertNull( $InputCheck->getError() );
 	}
 
@@ -29,7 +29,7 @@ class MathInputCheckTest extends MediaWikiTestCase {
 	 * @covers MathInputCheck::getValidTex
 	 */
 	public function testGetValidTex() {
-		$InputCheck = $this->getMockBuilder( 'MathInputCheck' )
+		$InputCheck = $this->getMockBuilder( MathInputCheck::class )
 			->setConstructorArgs( [ 'some tex input' ] )
 			->getMock();
 		$this->assertNull( $InputCheck->getValidTex() );
diff --git a/tests/phpunit/MathLaTeXMLDatabaseTest.php b/tests/phpunit/MathLaTeXMLDatabaseTest.php
index dbdc677..9aa3a33 100644
--- a/tests/phpunit/MathLaTeXMLDatabaseTest.php
+++ b/tests/phpunit/MathLaTeXMLDatabaseTest.php
@@ -23,7 +23,7 @@ class MathLaTeXMLDatabaseTest extends MediaWikiTestCase {
 	 * @return ReflectionMethod
 	 */
 	protected static function getMethod( $name ) {
-		$class = new ReflectionClass( 'MathLaTeXML' );
+		$class = new ReflectionClass( MathLaTeXML::class );
 		$method = $class->getMethod( $name );
 		$method->setAccessible( true );
 		return $method;
diff --git a/tests/phpunit/MathLaTeXMLTest.php b/tests/phpunit/MathLaTeXMLTest.php
index b4f9368..8bc510b 100644
--- a/tests/phpunit/MathLaTeXMLTest.php
+++ b/tests/phpunit/MathLaTeXMLTest.php
@@ -16,7 +16,7 @@ class MathLaTeXMLTest extends MediaWikiTestCase {
 	 * @covers MathLaTeXML::serializeSettings
 	 */
 	public function testSerializeSettings() {
-		$renderer = $this->getMockBuilder( 'MathLaTeXML' )
+		$renderer = $this->getMockBuilder( MathLaTeXML::class )
 			->setMethods( null )
 			->disableOriginalConstructor()
 			->getMock();
diff --git a/tests/phpunit/MathMathMLTest.php b/tests/phpunit/MathMathMLTest.php
index 8423e52..0ec6c28 100644
--- a/tests/phpunit/MathMathMLTest.php
+++ b/tests/phpunit/MathMathMLTest.php
@@ -65,12 +65,14 @@ class MathMathMLTest extends MediaWikiTestCase {
 		self::setMockValues( false, false, false );
 		$url = 'http://example.com/invalid';
 
-		$renderer = $this->getMockBuilder( 'MathMathML' )
+		$renderer = $this->getMockBuilder( MathMathML::class )
 				->setMethods( null )
 				->disableOriginalConstructor()
 				->getMock();
+
+		/** @var MathMathML $renderer */
 		$requestReturn = $renderer->makeRequest( $url, 'a+b', $res, $error,
-			'MathMLHttpRequestTester' );
+			MathMLHttpRequestTester::class );
 		$this->assertEquals( false, $requestReturn,
 			"requestReturn is false if HTTP::post returns false." );
 		$this->assertEquals( false, $res,
@@ -89,13 +91,14 @@ class MathMathMLTest extends MediaWikiTestCase {
 		self::setMockValues( true, true, false );
 		self::$content = 'test content';
 		$url = 'http://example.com/valid';
-		/** @var MathMathML */
-		$renderer = $this->getMockBuilder( 'MathMathML' )
+		$renderer = $this->getMockBuilder( MathMathML::class )
 				->setMethods( null )
 				->disableOriginalConstructor()
 				->getMock();
+
+		/** @var MathMathML $renderer */
 		$requestReturn = $renderer->makeRequest( $url, 'a+b', $res, $error,
-			'MathMLHttpRequestTester' );
+			MathMLHttpRequestTester::class );
 		$this->assertEquals( true, $requestReturn, "successful call return" );
 		$this->assertEquals( 'test content', $res, 'successful call' );
 		$this->assertEquals( $error, '', "successful call error-message" );
@@ -109,12 +112,14 @@ class MathMathMLTest extends MediaWikiTestCase {
 	public function testMakeRequestTimeout() {
 		self::setMockValues( false, true, true );
 		$url = 'http://example.com/timeout';
-		$renderer = $this->getMockBuilder( 'MathMathML' )
+		$renderer = $this->getMockBuilder( MathMathML::class )
 				->setMethods( null )
 				->disableOriginalConstructor()
 				->getMock();
+
+		/** @var MathMathML $renderer */
 		$requestReturn = $renderer->makeRequest(
-			$url, '$\longcommand$', $res, $error, 'MathMLHttpRequestTester'
+			$url, '$\longcommand$', $res, $error, MathMLHttpRequestTester::class
 		);
 		$this->assertEquals( false, $requestReturn, "timeout call return" );
 		$this->assertEquals( false, $res, "timeout call return" );
@@ -130,12 +135,14 @@ class MathMathMLTest extends MediaWikiTestCase {
 	public function testMakeRequestGetPostData() {
 		self::setMockValues( false, true, true );
 		$url = 'http://example.com/timeout';
-		$renderer = $this->getMockBuilder( 'MathMathML' )
+		$renderer = $this->getMockBuilder( MathMathML::class )
 			->setMethods( [ 'getPostData' ] )
 			->disableOriginalConstructor()
 			->getMock();
 		$renderer->expects( $this->once() )->method( 'getPostData' );
-		$renderer->makeRequest( $url, false, $res, $error, 'MathMLHttpRequestTester' );
+
+		/** @var MathMathML $renderer */
+		$renderer->makeRequest( $url, false, $res, $error, MathMLHttpRequestTester::class );
 	}
 
 	/**
@@ -146,12 +153,14 @@ class MathMathMLTest extends MediaWikiTestCase {
 	public function testMakeRequestGetHost() {
 		self::setMockValues( false, true, true );
 		$url = 'http://example.com/timeout';
-		$renderer = $this->getMockBuilder( 'MathMathML' )
+		$renderer = $this->getMockBuilder( MathMathML::class )
 			->setMethods( [ 'getPostData', 'pickHost' ] )
 			->disableOriginalConstructor()
 			->getMock();
 		$renderer->expects( $this->once() )->method( 'pickHost' );
-		$renderer->makeRequest( false, false, $res, $error, 'MathMLHttpRequestTester' );
+
+		/** @var MathMathML $renderer */
+		$renderer->makeRequest( false, false, $res, $error, MathMLHttpRequestTester::class );
 	}
 
 	/**
@@ -159,7 +168,7 @@ class MathMathMLTest extends MediaWikiTestCase {
 	 * @covers MathMathML::isValidMathML
 	 */
 	public function testisValidMathML() {
-		$renderer = $this->getMockBuilder( 'MathMathML' )
+		$renderer = $this->getMockBuilder( MathMathML::class )
 				->setMethods( null )
 				->disableOriginalConstructor()
 				->getMock();
@@ -175,7 +184,7 @@ class MathMathMLTest extends MediaWikiTestCase {
 	 * @covers MathMathML::isValidMathML
 	 */
 	public function testInvalidXml() {
-		$renderer = $this->getMockBuilder( 'MathMathML' )
+		$renderer = $this->getMockBuilder( MathMathML::class )
 			->setMethods( null )
 			->disableOriginalConstructor()
 			->getMock();
@@ -213,7 +222,7 @@ class MathMathMLTest extends MediaWikiTestCase {
 	public function testPickHost() {
 		$hosts = [ 'a', 'b', 'c' ];
 		$this->setMwGlobals( 'wgMathMathMLUrl', $hosts );
-		$class = new ReflectionClass( 'MathMathML' );
+		$class = new ReflectionClass( MathMathML::class );
 		$method = $class->getMethod( 'pickHost' );
 		$method->setAccessible( true );
 		srand( 0 ); // Make array_rand always return the same elements
@@ -239,7 +248,7 @@ class MathMathMLTest extends MediaWikiTestCase {
 class MathMLHttpRequestTester {
 
 	public static function factory() {
-		return new MathMLHttpRequestTester();
+		return new self();
 	}
 
 	public static function execute() {
diff --git a/tests/phpunit/MathRendererTest.php b/tests/phpunit/MathRendererTest.php
index 6a7e541..2416e65 100644
--- a/tests/phpunit/MathRendererTest.php
+++ b/tests/phpunit/MathRendererTest.php
@@ -38,7 +38,7 @@ class MathRendererTest extends MediaWikiTestCase {
 	 * @covers MathRenderer::__construct()
 	 */
 	public function testBasics() {
-		$renderer = $this->getMockForAbstractClass( 'MathRenderer', [ self::SOME_TEX ] );
+		$renderer = $this->getMockForAbstractClass( MathRenderer::class, [ self::SOME_TEX ] );
 		// check if the TeX input was corretly passed to the class
 		$this->assertEquals( self::SOME_TEX, $renderer->getTex(), "test getTex" );
 		$this->assertEquals( $renderer->isChanged(), false, "test if changed is initially false" );
@@ -50,7 +50,7 @@ class MathRendererTest extends MediaWikiTestCase {
 	 */
 	public function testWriteCacheSkip() {
 		$renderer =
-			$this->getMockBuilder( 'MathRenderer' )->setMethods( [
+			$this->getMockBuilder( MathRenderer::class )->setMethods( [
 					'writeToDatabase',
 					'render',
 					'getMathTableName',
@@ -66,7 +66,7 @@ class MathRendererTest extends MediaWikiTestCase {
 	 */
 	public function testWriteCache() {
 		$renderer =
-			$this->getMockBuilder( 'MathRenderer' )->setMethods( [
+			$this->getMockBuilder( MathRenderer::class )->setMethods( [
 					'writeToDatabase',
 					'render',
 					'getMathTableName',
@@ -78,7 +78,7 @@ class MathRendererTest extends MediaWikiTestCase {
 
 	public function testSetPurge() {
 		$renderer =
-			$this->getMockBuilder( 'MathRenderer' )->setMethods( [
+			$this->getMockBuilder( MathRenderer::class )->setMethods( [
 					'render',
 					'getMathTableName',
 					'getHtmlOutput'
@@ -90,7 +90,7 @@ class MathRendererTest extends MediaWikiTestCase {
 	public function testDisableCheckingAlways() {
 		$this->setMwGlobals( "wgMathDisableTexFilter", 'never' );
 		$renderer =
-			$this->getMockBuilder( 'MathRenderer' )->setMethods( [
+			$this->getMockBuilder( MathRenderer::class )->setMethods( [
 					'render',
 					'getMathTableName',
 					'getHtmlOutput',
@@ -108,7 +108,7 @@ class MathRendererTest extends MediaWikiTestCase {
 	public function testDisableCheckingNever() {
 		$this->setMwGlobals( "wgMathDisableTexFilter", 'always' );
 		$renderer =
-			$this->getMockBuilder( 'MathRenderer' )->setMethods( [
+			$this->getMockBuilder( MathRenderer::class )->setMethods( [
 					'render',
 					'getMathTableName',
 					'getHtmlOutput',
@@ -124,7 +124,7 @@ class MathRendererTest extends MediaWikiTestCase {
 	public function testCheckingNewUnknown() {
 		$this->setMwGlobals( "wgMathDisableTexFilter", 'new' );
 		$renderer =
-			$this->getMockBuilder( 'MathRenderer' )->setMethods( [
+			$this->getMockBuilder( MathRenderer::class )->setMethods( [
 					'render',
 					'getMathTableName',
 					'getHtmlOutput',
@@ -143,7 +143,7 @@ class MathRendererTest extends MediaWikiTestCase {
 	public function testCheckingNewKnown() {
 		$this->setMwGlobals( "wgMathDisableTexFilter", 'new' );
 		$renderer =
-			$this->getMockBuilder( 'MathRenderer' )->setMethods( [
+			$this->getMockBuilder( MathRenderer::class )->setMethods( [
 					'render',
 					'getMathTableName',
 					'getHtmlOutput',