- Add some additional test cases to verify behaviour for
  more than 2 repeating characters.
- Add some cases for testing the masking from the start of
  the string, before the start of the string and end of string.

(cherry picked from commit a91752882cbd1123d83847183441615f28928655)

Co-authored-by: Remy Bos <27890746+sjokkateer@users.noreply.github.com>