String#split("") should split per character (byte for now)

src/string.c

@@ -2208,14 +2208,24 @@ mrb_str_split_m(mrb_state *mrb, mrb_value str)
     char *ptr = RSTRING_PTR(str);
     char *temp = ptr;
     char *eptr = RSTRING_END(str);
-    char *sptr = RSTRING_PTR(spat);
     long slen = RSTRING_LEN(spat);
 
-    while (ptr < eptr &&
-	   (end = mrb_memsearch(sptr, slen, ptr, eptr - ptr)) >= 0) {
-      mrb_ary_push(mrb, result, mrb_str_subseq(mrb, str, ptr - temp, end));
-      ptr += end + slen;
-      if (lim >= 0 && lim <= ++i) break;
+    if (slen == 0) {
+      while (ptr < eptr) {
+	mrb_ary_push(mrb, result, mrb_str_subseq(mrb, str, ptr-temp, 1));
+	ptr++;
+	if (lim >= 0 && lim <= ++i) break;
+      }
+    }
+    else {
+      char *sptr = RSTRING_PTR(spat);
+
+      while (ptr < eptr &&
+	     (end = mrb_memsearch(sptr, slen, ptr, eptr - ptr)) >= 0) {
+	mrb_ary_push(mrb, result, mrb_str_subseq(mrb, str, ptr - temp, end));
+	ptr += end + slen;
+	if (lim >= 0 && lim <= ++i) break;
+      }
     }
     beg = ptr - temp;
   }

test/t/string.rb

@@ -275,13 +275,10 @@ end
 # TODO Broken ATM
 assert('String#split', '15.2.10.5.35') do
   # without RegExp behavior is actually unspecified
-  a = 'abc abc abc'.split
-  b = 'a,b,c,,d'.split(',')
-  c = 'abc abc abc'.split(nil)
-
-  a == ['abc', 'abc', 'abc'] and
-    b == ["a", "b", "c", "", "d"] and
-    c == ['abc', 'abc', 'abc']
+  'abc abc abc'.split == ['abc', 'abc', 'abc'] and
+    'a,b,c,,d'.split(',') == ["a", "b", "c", "", "d"] and
+    'abc abc abc'.split(nil) == ['abc', 'abc', 'abc'] and
+    'abc'.split("") == ['a', 'b', 'c']
 end
 
 # TODO ATM broken assert('String#sub', '15.2.10.5.36') do