/** * Extended method via interface test. * @return void */ public function testExtendedMethodViaInterface() { TestClass::extensionMethod('IFirst::joinI', 'IFirst_join'); TestClass::extensionMethod('ISecond::joinI', 'ISecond_join'); $obj = new TestClass('Hello', 'World'); $this->assertEquals("ISecond_join says Hello World", $obj->joinI(" ")); }