public function testImmutableMethods()
{
$url = new Url('http://example.com/about.htm');
$this->assertSame('https://example.com/about.htm', (string) $url->scheme('https'));
$this->assertSame('http://example.nl/about.htm', (string) $url->host('example.nl'));
$this->assertSame('http://example.com:8080/about.htm', (string) $url->port(8080));
$this->assertSame('http://example.com/disclaimer.htm', (string) $url->path('disclaimer.htm'));
$this->assertSame('http://example.com/about.htm?param1=one', (string) $url->query(['param1' => 'one']));
$this->assertSame('http://example.com/about.htm?param2=two', (string) $url->parameter('param2', 'two'));
$this->assertSame('http://example.com/about.htm#author', (string) $url->fragment('author'));
$this->assertEquals('http://example.com/about.htm', $url, 'Original url is unchanged');
}