PHPUnit StackTest::assertEmpty() deprecated

[beta123]

I am learning building php unit tests using PHPUnit . There they have a manual and I encountered this example Where they use assertEmpty(), but when I run this code in command line I get this error : \[code\]Call to undefined method StackTest::assertEmpty() in /var/www/.../tests/StackTest.php on line 20\[/code\]. So if this method is deprecated or something why they use it , also is there another method for this? (of course I can try this \[code\]$this->assertEquals(0, count($stack));\[/code\]) but anyways...The same with \[code\]assertNotEmpty()\[/code\].