Zend\Code\Generator\ParameterGenerator::setDefaultValue PHP Method

    public function setDefaultValue($defaultValue)
    {
        if (!$defaultValue instanceof ValueGenerator) {
            $defaultValue = new ValueGenerator($defaultValue);
        }
        $this->defaultValue = $defaultValue;
        return $this;
    }

 public function testGenerateIsCorrect()
 {
     $parameterGenerator = new ParameterGenerator();
     $parameterGenerator->setType('Foo');
     $parameterGenerator->setName('bar');
     $parameterGenerator->setDefaultValue(15);
     $this->assertEquals('Foo $bar = 15', $parameterGenerator->generate());
     $parameterGenerator->setDefaultValue('foo');
     $this->assertEquals('Foo $bar = \'foo\'', $parameterGenerator->generate());
 }