public function test_action_args_1() {
    $a   = new MockAction();
    $tag = __FUNCTION__;
    $val = __FUNCTION__ . '_val';

    add_action( $tag, array( &$a, 'action' ) );
    // Call the action with a single argument.
    do_action( $tag, $val );

    $call_count = $a->get_call_count();
    $this->assertSame( 1, $call_count );
    $argsvar = $a->get_args();
    $this->assertSame( array( $val ), array_pop( $argsvar ) );
  }