“ indirect fixture” error using pytest. What is wrong?

Question

 def fatorial(n):     if n <= 1:         return 1     else:         return n*fatorial(n - 1)   import pytest  @pytest.mark.parametrize("entrada","esperado",[     (0,1),     (1,1),     (2,2),     (3,6),     (4,24),     (5,120) ])  def testa_fatorial(entrada,esperado):     assert fatorial(entrada)  == esperado 

The error:

 ERROR collecting Fatorial_pytest.py ____________________________________________________________________ In testa_fatorial: indirect fixture '(0, 1)' doesn't exist 

I dont know why I got "indirect fixture”. Any idea? I am using python 3.7 and windows 10 64 bits.

Answer 1

TL;DR -
The problem is with the line

@pytest.mark.parametrize("entrada","esperado",[ ... ]) 

It should be written as a comma-separated string:

@pytest.mark.parametrize("entrada, esperado",[ ... ]) 

---

You got the indirect fixture because pytest couldn't unpack the given argvalues since it got a wrong argnames parameter. You need to make sure all parameters are written as one string.

Please see the documentation:

The builtin pytest.mark.parametrize decorator enables parametrization of arguments for a test function.

Parameters:
1. argnames – a comma-separated string denoting one or more argument names, or a list/tuple of argument strings.
2. argvalues – The list of argvalues determines how often a test is invoked with different argument values.

Meaning, you should write the arguments you want to parametrize as a single string and separate them using a comma. Therefore, your test should look like this:

@pytest.mark.parametrize("n, expected", [     (0, 1),     (1, 1),     (2, 2),     (3, 6),     (4, 24),     (5, 120) ]) def test_factorial(n, expected):     assert factorial(n) == expected