Missing test in std.string.replace

[simendsjo]

On 10.08.2010 00:29, simendsjo wrote:
> Replacing with "" / null is missing.
> I first looked at the function and modified it. Quickly noticed that a
> few unit tests were missing:
>
> assert(replace("foo", "foo", "") == "");
> assert(replace("foo", "foo", null) == "");

I refactored replace to understand what was going on (related to my post 
"is this more readable").
I've seen a couple of functions using Appender, and it's documentation 
says it's faster than ~=. I tried to change char[] result to Appender, 
but dmd crashed...


string replace(string s, string from, string to)
{
     if (from.length == 0) // Nothing to replace
         return s;

     char[] result;
     for (size_t searchIndex; searchIndex < s.length; )
     {
         auto rest = s[searchIndex .. s.length];
         auto fromIndex = indexOf(rest, from);

         bool nothingToReplace = (fromIndex == -1);
         if (nothingToReplace)
         {
             bool firstSearch = (searchIndex == 0);
             if (firstSearch)
             {
                 // Never found, so just return s
                 return s;
             }

             result ~= rest;
             break;
         }

         auto beforeFrom = s[searchIndex .. searchIndex + fromIndex];
         result ~= beforeFrom;
         result ~= to;

         searchIndex += fromIndex + from.length;
     }

     return assumeUnique(result);
}