CODEWITHSUNDEEP
pythonunit-testing
J.D
J.D

Reputation: 45

Python Unittest: TypeError: __init__() missing

I am very new to Unit Testing in Python. I was writing a unit test for a very small method. The code implementation is a follows. But if I run the test script, I get an error saying :

TypeError: __init__() missing 4 required positional arguments: 'x ,'y','z','w' 

class get_result():
    def __init__(self,x,y,z,w):
        self.x=x
        self.y=y
        self.z=z
        self.w=w


    def generate_result(self):
        curr_x= 90
        dist= curr_x-self.x
        return dist


import unittest
from sample import get_result
result = get_result()

class Test(unittest.TestCase):

    def test_generate_result(self):
        self.assertEqual(somevalue, result.generate_result())

Upvotes: 1

Views: 1774

Answers (2)

Chen A.
Chen A.

Reputation: 11280

Your __init__ method requires 4 arguments, and when not provided raise an error.

If you want to to support optional position argument you can define init as follows: __init__(self, *args, **kwargs) and then handle them inside the function. Pay attention that if not provided, the object still gets created and if you don't validate the values exist you'll encounter the error at a later stage in your code. You can catch this exception and print more readable error:

>>> class GetResult():
    def __init__(self, *args, **kwargs):
        if len(args) < 4:
            raise Exception('one or more required parameters x, y, w, z is missing')
.. rest code here

>>> g = GetResult()

Traceback (most recent call last):
  File "<pyshell#87>", line 1, in <module>
    g = GetResult()
  File "<pyshell#86>", line 4, in __init__
    raise Exception('one or more required parameters x, y, w, z is missing')
Exception: one or more required parameters x, y, w, z is missing

Upvotes: 0

BHawk
BHawk

Reputation: 2462

result = get_result() should be result = get_result(xvalue,yvalue,zvalue,wvalue)

Where those values == some number. Or as PRMoureu suggests you can make them optional arguments in your declaration of your __init__() method.

Upvotes: 2

Related Questions