How can generate automatically test case number in unittest?

Question

how can I generate automatically the numbers of test cases in unittest? I mean something like test_01, test_02, test_{generate number}.

import unittest 

class TestSum(unittest.TestCase): 
    def test_01_sum(self): 
        self.assertEqual(sum([1, 2, 3]), 6, "Should be 6") 

    def test_02_sum_tuple(self): 
        self.assertEqual(sum((1, 2, 2)), 6, "Should be 6") 

if name == '__main__': 
   unittest.main()

Can you please add more details about what you're trying to achieve? Do you want to generate source code? How would your "before" and "after" look like? — gnvk, Oct 05 '19 at 07:21
@r4ch only that I need is instead of test_01_sum I need test_ {generate number}_sum — andrew_k, Oct 05 '19 at 07:26

gnvk · Accepted Answer · 2019-10-05T10:02:56.597

To achieve this at runtime, you can actually rename the test methods for your test class:

def generate_test_numbers(test_class):
    counter = 1
    for method_name in dir(test_class):
        if not method_name.startswith('test_N_'):
            continue
        method = getattr(test_class, method_name)
        if not callable(method):
            continue
        new_method_name = method_name.replace('_N_', '_{:02d}_'.format(counter))
        counter += 1
        setattr(test_class, new_method_name, method)
        delattr(test_class, method_name)
    return test_class

You can either simply call this function from main:

generate_test_numbers(TestSum)

or as @VPfB suggested it, use it as a class decorator:

@generate_test_numbers
class TestSum(unittest.TestCase): 
    def test_N_sum(self): 
        self.assertEqual(sum([1, 2, 3]), 6, "Should be 6") 

    def test_N_sum_tuple(self): 
        self.assertEqual(sum((1, 2, 2)), 6, "Should be 6")

Either will output (with -v)

test_01_sum (__main__.TestSum) ... ok
test_02_sum_tuple (__main__.TestSum) ... FAIL

======================================================================
FAIL: test_02_sum_tuple (__main__.TestSum)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "q.py", line 8, in test_N_sum_tuple
    self.assertEqual(sum((1, 2, 2)), 6, "Should be 6")
AssertionError: 5 != 6 : Should be 6

----------------------------------------------------------------------
Ran 2 tests in 0.001s

FAILED (failures=1)

thank you for your answer it's works perfect for me – andrew_k Oct 05 '19 at 08:53 — andrew_k, Oct 05 '19 at 08:53
that would be a nice class decorator – VPfB Oct 05 '19 at 09:51 — VPfB, Oct 05 '19 at 09:51
@VPfB added class decorator example to the answer – gnvk Oct 05 '19 at 10:03 — gnvk, Oct 05 '19 at 10:03

How can generate automatically test case number in unittest?

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