add_querystring_var() and remove_querystring_var() improvements, with tests

querystring.php

<?php


/**
 * Add the querystring variable $key with a value $value to $url.
 * If $key is already specified within $url, it will replace it.
 * 
 * Based upon http://www.addedbytes.com/code/querystring-functions/
 * 
 * @param string $url
 * @param string $key
 * @param string[optional] $value
 * @return string
 */
function add_querystring_var($url, $key, $value = '') {
    $url = preg_replace('/(.*)(\?|&)' . $key . '=[^&]+?(&)(.*)/i', '$1$2$4', $url . '&');
    $url = substr($url, 0, -1);
    
    $value = $value ? "=".urlencode($value) : '';
    
    if (strpos($url, '?') === false)
        return ($url . '?' . $key . $value);
    else
        return ($url . '&' . $key . $value);
}

/**
 * Remove the Querystring variable $key and its value from the given $url.
 * @param string $url
 * @param string $key
 * @return string
 */
function remove_querystring_var($url, $key) {
    $parts = parse_url($url);
	$qs = isset($parts['query']) ? $parts['query'] : '';
	$base = $qs ? mb_substr($url, 0, mb_strpos($url, '?')) : $url; // all of URL except QS
	
	parse_str($qs, $qsParts);
	unset($qsParts[$key]);
	$newQs = rtrim(http_build_query($qsParts), '=');
	
	if ($newQs)
		return $base.'?'.$newQs;
	else
		return $base;
}

QueryStringTest.php

<?php

class QueryStringTest extends PHPUnit_Framework_TestCase {
	
	/**
	 * @covers remove_querystring_var
	 */
	public function testRemoveQueryStringVar() {
		
		// tests without any other querystring params
		$urls = array(
			'http://example.com/faqs/foo-bar/',
			'http://example.com/faqs/foo-bar/?removeme',
			'http://example.com/faqs/foo-bar/?removeme=',
			'http://example.com/faqs/foo-bar/?removeme&',
			'http://example.com/faqs/foo-bar/?removeme=en',
			'http://example.com/faqs/foo-bar/?removeme=en&',
		);
		$expected = $urls[0];
		
		foreach($urls as $k => $url)
			$this->assertEquals($expected, remove_querystring_var($url, 'removeme'), 'First batch: $urls['.$k.'] has a problem.');
		
		// tests with other querystring params
		$urls = array(
			'http://example.com/faqs/foo-bar/?foo',
			'http://example.com/faqs/foo-bar/?removeme=en&foo',
			'http://example.com/faqs/foo-bar/?removeme=en&foo&another=foo',
			'http://example.com/faqs/foo-bar/?foo&removeme&',
			'http://example.com/faqs/foo-bar/?foo&removeme',
			'http://example.com/faqs/foo-bar/?foo&removeme=',
			'http://example.com/faqs/foo-bar/?foo&removeme=&',
			'http://example.com/faqs/foo-bar/?foo&removeme=en',
			'http://example.com/faqs/foo-bar/?foo&removeme=en&',
			'http://example.com/faqs/foo-bar/?foo&removeme=en&another=foo',
		);
		$expected = $urls[0];
		
		foreach($urls as $k => $url)
			$this->assertEquals($expected, remove_querystring_var(remove_querystring_var($url, 'removeme'), 'another'), 'Second batch: $urls['.$k.'] has a problem.');
		
		// some tests without a full URL without any other querystring params
		$urls = array(
			'/faqs/foo-bar/',
			'/faqs/foo-bar/?removeme',
			'/faqs/foo-bar/?removeme=',
			'/faqs/foo-bar/?removeme&',
			'/faqs/foo-bar/?removeme=en',
			'/faqs/foo-bar/?removeme=en&',
			'/faqs/foo-bar/?removeme=en&another',
			'/faqs/foo-bar/?removeme=en&another=',
			'/faqs/foo-bar/?removeme=en&another=foo',
			'/faqs/foo-bar/?another&removeme',
			'/faqs/foo-bar/?another&removeme=',
			'/faqs/foo-bar/?another=hi&removeme&',
			'/faqs/foo-bar/?another&removeme=en',
			'/faqs/foo-bar/?another&removeme=en&',
		);
		$expected = $urls[0];
		
		foreach($urls as $k => $url)
			$this->assertEquals($expected, remove_querystring_var(remove_querystring_var($url, 'removeme'), 'another'), 'Third batch: $urls['.$k.'] has a problem.');
		
		// some tests without a full URL with other querystring params
		$urls = array(
			'/faqs/foo-bar/?foo=baz',
			'/faqs/foo-bar/?removeme=en&foo=baz',
			'/faqs/foo-bar/?removeme=en&foo=baz&another=foo',
			'/faqs/foo-bar/?foo=baz&removeme&',
			'/faqs/foo-bar/?foo=baz&removeme',
			'/faqs/foo-bar/?foo=baz&removeme=',
			'/faqs/foo-bar/?foo=baz&removeme=&',
			'/faqs/foo-bar/?foo=baz&removeme=en',
			'/faqs/foo-bar/?foo=baz&removeme=en&',
			'/faqs/foo-bar/?foo=baz&removeme=en&another=foo',
		);
		$expected = $urls[0];
		
		foreach($urls as $k => $url)
			$this->assertEquals($expected, remove_querystring_var(remove_querystring_var($url, 'removeme'), 'another'), 'Fourth batch: $urls['.$k.'] has a problem.');
		
	}

}

how to use remove query..
i want remove ?goto.php=
http://localhost/1/frame/goto.php?u=http://randomsite.com/zzz
rewrite to
http://localhost/1/frame/http://randomsite.com/zzz