README.md

Pytest "integer is self" behavior

pip install pytest && pytest test_integers.py

Why do only some of the tests pass?

test_integers.py

import pytest

range1 = range(-10, 260)
range2 = range(-10, 260)
labels = map(str, range1)


@pytest.fixture(params=zip(range1, range2), ids=labels)
def integers(request):
    return request.param


def test_integer_is_itself(integers):
    a, b = integers
    assert a is b

zOUTPUT.md

============================= test session starts ==============================
platform darwin -- Python 3.7.0, pytest-4.0.1, py-1.6.0, pluggy-0.7.1
rootdir: /Users/thopper, inifile:
plugins: sugar-0.9.2
collected 270 items

test_integers.py FFFFF.................................................. [ 20%]
........................................................................ [ 47%]
........................................................................ [ 73%]
....................................................................FFF  [100%]

=================================== FAILURES ===================================
_________________________ test_integer_is_itself[-10] __________________________

integers = (-10, -10)

    def test_integer_is_itself(integers):
        a, b = integers
>       assert a is b
E       assert -10 is -10

test_integers.py:12: AssertionError
__________________________ test_integer_is_itself[-9] __________________________

integers = (-9, -9)

    def test_integer_is_itself(integers):
        a, b = integers
>       assert a is b
E       assert -9 is -9

test_integers.py:12: AssertionError
__________________________ test_integer_is_itself[-8] __________________________

integers = (-8, -8)

    def test_integer_is_itself(integers):
        a, b = integers
>       assert a is b
E       assert -8 is -8

test_integers.py:12: AssertionError
__________________________ test_integer_is_itself[-7] __________________________

integers = (-7, -7)

    def test_integer_is_itself(integers):
        a, b = integers
>       assert a is b
E       assert -7 is -7

test_integers.py:12: AssertionError
__________________________ test_integer_is_itself[-6] __________________________

integers = (-6, -6)

    def test_integer_is_itself(integers):
        a, b = integers
>       assert a is b
E       assert -6 is -6

test_integers.py:12: AssertionError
_________________________ test_integer_is_itself[257] __________________________

integers = (257, 257)

    def test_integer_is_itself(integers):
        a, b = integers
>       assert a is b
E       assert 257 is 257

test_integers.py:12: AssertionError
_________________________ test_integer_is_itself[258] __________________________

integers = (258, 258)

    def test_integer_is_itself(integers):
        a, b = integers
>       assert a is b
E       assert 258 is 258

test_integers.py:12: AssertionError
_________________________ test_integer_is_itself[259] __________________________

integers = (259, 259)

    def test_integer_is_itself(integers):
        a, b = integers
>       assert a is b
E       assert 259 is 259

test_integers.py:12: AssertionError
===================== 8 failed, 262 passed in 0.36 seconds =====================