Write a python function to count number of non-empty substrings of a given string.
def number_of_substrings(str): 
	str_len = len(str); 
	return int(str_len * (str_len + 1) / 2); 
<s>[INST]<<SYS>>Given a task and its code, generate test cases for the code.<</SYS>>Write a python function to count number of non-empty substrings of a given string.
def number_of_substrings(str): 
	str_len = len(str); 
	return int(str_len * (str_len + 1) / 2); [/INST]assert number_of_substrings("abc") == 6
assert number_of_substrings("abcd") == 10
assert number_of_substrings("abcde") == 15</s>