public function testReturn()
{
    $g = new Horde_Service_Gravatar();
    $this->assertType('string', $g->getId('test'));
}

public function testAddress()
{
    $g = new Horde_Service_Gravatar();
    $this->assertEquals(
        '0c17bf66e649070167701d2d3cd71711',
        $g->getId('test@example.org')
    );
}

/**
 * @dataProvider provideAddresses
 */
public function testAddresses($mail, $id)
{
    $g = new Horde_Service_Gravatar();
    $this->assertEquals($id, $g->getId($mail));
}

public function provideAddresses()
{
    return array(
        array('test@example.org', '0c17bf66e649070167701d2d3cd71711'),
        array('x@example.org', 'ae46d8cbbb834a85db7287f8342d0c42'),
        array('test@example.com', '55502f40dc8b7c769880b10874abc9d0'),
    );
}