Sometimes there is a situation when we want to check if the tested result is within the proper range. An example of such a situation would be a function that returns the PI number. Pi is an irrational number, which means it can’t be expressed as a simple fraction. Because of that, we are not sure with what accuracy the result will be returned. The proper approach is to test whether the function result is within the given range. In the case of Pi, the range will be from 3.1415 to 3.1416.
Firstly let's write a function like in the snipped below:
import math
def get_pi():
return math.pi
To test get_pi function correctness we will just check if the result is in the range of 3.1415 to 3.1416.
from sources.operations import get_pi
def test_get_pi():
assert 3.1415 <= get_pi() <= 3.1416
Test passed. As expected, the get_pi() method returns Pi value within a range from 3.1415 to 3.1416.