Fix phpunit methods

Author: tomas-novotny

tests/Builder/DefaultDocumentFactoryTest.php

@@ -62,10 +62,10 @@ public function testCreateForContentMethodWithInvalidXml2(): void
         $this->expectExceptionMessage('DOMDocument::loadXML()');
 
         $document = $this->createMock(DOMDocument::class);
-        $document->expects(self::once())->method('loadXML')->willReturn(false);
+        $document->expects($this->once())->method('loadXML')->willReturn(false);
 
         $factory = $this->createMock(DOMDocumentFactory::class);
-        $factory->expects(self::once())->method('create')->willReturn($document);
+        $factory->expects($this->once())->method('create')->willReturn($document);
 
         $factory = $this->newDocumentFactory($factory);
 

tests/Builder/DefaultDocumentTest.php

@@ -77,7 +77,7 @@ public function testToStringFailed(): void
         $this->expectExceptionMessage('DOMDocument::saveXML() method failed');
 
         $document = $this->createMock(DOMDocument::class);
-        $document->expects(self::once())->method('saveXML')->willReturn(false);
+        $document->expects($this->once())->method('saveXML')->willReturn(false);
 
         $xml = new DefaultDocument($document);
 
@@ -469,7 +469,7 @@ public function testValidateXsdFailed(): void
         $this->expectExceptionMessage('DOMDocument::schemaValidate() method failed');
 
         $document = $this->createMock(DOMDocument::class);
-        $document->expects(self::once())->method('schemaValidate')->willReturn(false);
+        $document->expects($this->once())->method('schemaValidate')->willReturn(false);
 
         $xml = new DefaultDocument($document);
 
@@ -636,7 +636,7 @@ public function testSaveMethodFailed(): void
         $this->expectExceptionMessage('DOMDocument::save() method failed');
 
         $document = $this->createMock(DOMDocument::class);
-        $document->expects(self::once())->method('save')->willReturn(false);
+        $document->expects($this->once())->method('save')->willReturn(false);
 
         $xml = new DefaultDocument($document);