Time for action – writing a unit test
We will write tests for a simple factorial function. The tests will check for the so-called happy path and abnormal conditions.
Start by writing the factorial function:
import numpy as np import unittest def factorial(n): if n == 0: return 1 if n < 0: raise ValueError, "Unexpected negative value" return np.arange(1, n+1).cumprod()
The code uses the
arange()
andcumprod()
functions to create arrays and calculate the cumulative product, but we added a few checks for boundary conditions.Now we will write the unit test. Let's write a class that will contain the unit tests. It extends the
TestCase
class from theunittest
module, which is part of standard Python. Test for calling the factorial function with the following three attributes:a positive number, the happy path
boundary condition 0
negative numbers, which should result in an error
class FactorialTest(unittest.TestCase): def test_factorial(self): #Test for the factorial...