public function test_action_args_3() {
    $a1   = new MockAction();
    $a2   = new MockAction();
    $a3   = new MockAction();
    $tag  = __FUNCTION__;
    $val1 = __FUNCTION__ . '_val1';
    $val2 = __FUNCTION__ . '_val2';

    // $a1 accepts two arguments, $a2 doesn't, $a3 accepts two arguments.
    add_action( $tag, array( &$a1, 'action' ), 10, 2 );
    add_action( $tag, array( &$a2, 'action' ) );
    add_action( $tag, array( &$a3, 'action' ), 10, 2 );
    // Call the action with two arguments.
    do_action( $tag, $val1, $val2 );

    $call_count = $a1->get_call_count();
    // $a1 should be called with both args.
    $this->assertSame( 1, $call_count );
    $argsvar1 = $a1->get_args();
    $this->assertSame( array( $val1, $val2 ), array_pop( $argsvar1 ) );

    // $a2 should be called with one only.
    $this->assertSame( 1, $a2->get_call_count() );
    $argsvar2 = $a2->get_args();
    $this->assertSame( array( $val1 ), array_pop( $argsvar2 ) );

    // $a3 should be called with both args.
    $this->assertSame( 1, $a3->get_call_count() );
    $argsvar3 = $a3->get_args();
    $this->assertSame( array( $val1, $val2 ), array_pop( $argsvar3 ) );
  }