riched20/tests: Test EM_GETTEXTRANGE with multibyte character.

dlls/riched20/tests/editor.c

@@ -1542,6 +1542,19 @@ static void test_EM_GETTEXTRANGE(void)
     ok(result == strlen(text2), "EM_GETTEXTRANGE returned %ld\n", result);
     ok(!strcmp(text2, buffer), "EM_GETTEXTRANGE filled %s\n", buffer);
 
+    /* Test with multibyte character */
+    if (!is_lang_japanese)
+        skip("Skip multibyte character tests on non-Japanese platform\n");
+    else
+    {
+        SendMessageA(hwndRichEdit, WM_SETTEXT, 0, (LPARAM)"abcdef\x8e\xf0ghijk");
+        textRange.chrg.cpMin = 4;
+        textRange.chrg.cpMax = 8;
+        result = SendMessageA(hwndRichEdit, EM_GETTEXTRANGE, 0, (LPARAM)&textRange);
+        todo_wine ok(result == 5, "EM_GETTEXTRANGE returned %ld\n", result);
+        todo_wine ok(!strcmp("ef\x8e\xf0g", buffer), "EM_GETTEXTRANGE filled %s\n", buffer);
+    }
+
     DestroyWindow(hwndRichEdit);
 }