assertContainsOnlyInstancesOf()

<?php
use PHPUnit\Framework\TestCase;

class ContainsOnlyInstancesOfTest extends TestCase
{
    public function testFailure()
    {
        $this->assertContainsOnlyInstancesOf(
            Foo::class,
            [new Foo, new Bar, new Foo]
        );
    }
}
?>

phpunit ContainsOnlyInstancesOfTest
PHPUnit 5.6.0 by Sebastian Bergmann and contributors.

F

Time: 0 seconds, Memory: 5.00Mb

There was 1 failure:

1) ContainsOnlyInstancesOfTest::testFailure
Failed asserting that Array ([0]=> Bar Object(...)) is an instance of class "Foo".

/home/sb/ContainsOnlyInstancesOfTest.php:6

FAILURES!
Tests: 1, Assertions: 1, Failures: 1.