Added edit_distance test cases

Author: kathrynpete

strings/edit_distance.py

@@ -14,6 +14,20 @@ def edit_distance(source: str, target: str) -> int:
 
  >>> edit_distance("GATTIC", "GALTIC")
  1
+ >>> edit_distance("NUM3", "HUM2")
+ 2
+ >>> edit_distance("cap","CAP")
+ 3
+ >>> edit_distance("Cat","")
+ 3
+ >>> edit_distance("cat","cat")
+ 0
+ >>> edit_distance("","123456789")
+ 9
+ >>> edit_distance("Be@uty","Beautyyyy!")
+ 5
+ >>> edit_distance("lstring","lsstring")
+ 1
  """
  if len(source) == 0:
  return len(target)