$this->assertEquals(l('Home', 'node'), '<a href="/">Home</a>');
$this->assertEquals(l('Some page', 'node/34'), '<a href="/node/34">some page</a>');
$this->assertEquals(l('Some page', 'node/34', array('class' => 'foobar')), '<a href="/node/34" class="foobar">some page</a>');