When using PHPUnit you can mark which classes/methods a test method is designed to exercise using @covers docblock annotations on classes and methods. It would be great to get code navigation (CTRL + Click) on these elements.

    /**
     * @covers User::setName        <-- CTRL + Hover shows documentation
     * @covers User::getName        <-- CTRL + Click goes to class/method
     */
    function testSetName() {
        $user = new User();
        $user->setName('joe');
        assertThat($user->getName(), is('joe'));
    }

PHP_CodeCoverage supports some alternate forms such as

    @covers User::<public
    @covers User::!<private

and IIRC a form that says "class X and all super/subclasses".