从右至左的问题弄乱了结果，特别是"@"字符.将您的功能修改为:

It is the right-to-left issue that messes up the results, in specific, it is the "@" char. modify your function to:

public void Fancy_placeholder_should_be_replaced()
    {
        const string input = "(השדה @%1$ קצר מדי (@%2$ תווים לפחות";
        const string expected = "(השדה {0} קצר מדי ({1} תווים לפחות";

        var formatted = input.Replace("@%2$", "{1}");
        formatted = formatted.Replace("@%1$", "{0}");

        bool same2 = expected == formatted;
        Assert.AreEqual(expected, formatted);
    }

和田田！它有效...

And tada! it works...