Sokil\Mongo\DocumentValidationTest::testIsValid_FieldNull PHP Method

    public function testIsValid_FieldNull()
    {
        // mock of document
        $document = $this->getMock('\\Sokil\\Mongo\\Document', array('rules'), array($this->collection));
        $document->expects($this->any())->method('rules')->will($this->returnValue(array(array('some-field-name', 'null'))));
        // required field empty
        $this->assertTrue($document->isValid());
        // required field set to wrong value
        $document->set('some-field-name', 'wrongValue');
        $this->assertFalse($document->isValid());
        // required field set to valid value
        $document->set('some-field-name', null);
        $this->assertTrue($document->isValid());
    }