text: #include "stringfn.h"
  #include "test.h"
  
  
  void test_impl()
  {
    char *string = stringfn_substring("", 0, 0);
  
    assert_string_equal(string, "");
  
    free(string);
  }
  
  
  int main()
  {
    test_run(test_impl);
  }
  
  