public function test_remove_all_action() {
    $a   = new MockAction();
    $tag = __FUNCTION__;

    add_action( 'all', array( &$a, 'action' ) );
    $this->assertSame( 10, has_filter( 'all', array( &$a, 'action' ) ) );
    do_action( $tag );

    // Make sure our hook was called correctly.
    $this->assertSame( 1, $a->get_call_count() );
    $this->assertSame( array( $tag ), $a->get_tags() );

    // Now remove the action, do it again, and make sure it's not called this time.
    remove_action( 'all', array( &$a, 'action' ) );
    $this->assertFalse( has_filter( 'all', array( &$a, 'action' ) ) );
    do_action( $tag );
    $this->assertSame( 1, $a->get_call_count() );
    $this->assertSame( array( $tag ), $a->get_tags() );
  }