OptionTest::testFromReturn()

    public function testFromReturn()
    {
        $null = function() { return null; };
        $false = function() { return false; };
        $some = function() { return 'foo'; };

        $this->assertTrue(\PhpOption\Option::fromReturn($null)->isEmpty());
        $this->assertFalse(\PhpOption\Option::fromReturn($false)->isEmpty());
        $this->assertTrue(\PhpOption\Option::fromReturn($false, array(), false)->isEmpty());
        $this->assertTrue(\PhpOption\Option::fromReturn($some)->isDefined());
        $this->assertFalse(\PhpOption\Option::fromReturn($some, array(), 'foo')->isDefined());
    }