Demo of Python failure reports with pytestΒΆ

Here is a nice run of several tens of failures and how pytest presents things (unfortunately not showing the nice colors here in the HTML that you get on the terminal - we are working on that):

assertion $ py.test failure_demo.py
=========================== test session starts ============================
platform linux2 -- Python 2.7.3 -- py-1.4.20 -- pytest-2.5.2
collected 39 items

failure_demo.py FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF

================================= FAILURES =================================
____________________________ test_generative[0] ____________________________

param1 = 3, param2 = 6

    def test_generative(param1, param2):
>       assert param1 * 2 < param2
E       assert (3 * 2) < 6

failure_demo.py:15: AssertionError
_________________________ TestFailing.test_simple __________________________

self = <failure_demo.TestFailing object at 0x29e5210>

    def test_simple(self):
        def f():
            return 42
        def g():
            return 43

>       assert f() == g()
E       assert 42 == 43
E        +  where 42 = <function f at 0x296a9b0>()
E        +  and   43 = <function g at 0x296aa28>()

failure_demo.py:28: AssertionError
____________________ TestFailing.test_simple_multiline _____________________

self = <failure_demo.TestFailing object at 0x29cef50>

    def test_simple_multiline(self):
        otherfunc_multi(
                  42,
>                 6*9)

failure_demo.py:33:
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

a = 42, b = 54

    def otherfunc_multi(a,b):
>       assert (a ==
                b)
E       assert 42 == 54

failure_demo.py:11: AssertionError
___________________________ TestFailing.test_not ___________________________

self = <failure_demo.TestFailing object at 0x29be250>

    def test_not(self):
        def f():
            return 42
>       assert not f()
E       assert not 42
E        +  where 42 = <function f at 0x296ac08>()

failure_demo.py:38: AssertionError
_________________ TestSpecialisedExplanations.test_eq_text _________________

self = <failure_demo.TestSpecialisedExplanations object at 0x29c3990>

    def test_eq_text(self):
>       assert 'spam' == 'eggs'
E       assert 'spam' == 'eggs'
E         - spam
E         + eggs

failure_demo.py:42: AssertionError
_____________ TestSpecialisedExplanations.test_eq_similar_text _____________

self = <failure_demo.TestSpecialisedExplanations object at 0x2acef90>

    def test_eq_similar_text(self):
>       assert 'foo 1 bar' == 'foo 2 bar'
E       assert 'foo 1 bar' == 'foo 2 bar'
E         - foo 1 bar
E         ?     ^
E         + foo 2 bar
E         ?     ^

failure_demo.py:45: AssertionError
____________ TestSpecialisedExplanations.test_eq_multiline_text ____________

self = <failure_demo.TestSpecialisedExplanations object at 0x29f1f50>

    def test_eq_multiline_text(self):
>       assert 'foo\nspam\nbar' == 'foo\neggs\nbar'
E       assert 'foo\nspam\nbar' == 'foo\neggs\nbar'
E           foo
E         - spam
E         + eggs
E           bar

failure_demo.py:48: AssertionError
______________ TestSpecialisedExplanations.test_eq_long_text _______________

self = <failure_demo.TestSpecialisedExplanations object at 0x29e58d0>

    def test_eq_long_text(self):
        a = '1'*100 + 'a' + '2'*100
        b = '1'*100 + 'b' + '2'*100
>       assert a == b
E       assert '111111111111...2222222222222' == '1111111111111...2222222222222'
E         Skipping 90 identical leading characters in diff, use -v to show
E         Skipping 91 identical trailing characters in diff, use -v to show
E         - 1111111111a222222222
E         ?           ^
E         + 1111111111b222222222
E         ?           ^

failure_demo.py:53: AssertionError
_________ TestSpecialisedExplanations.test_eq_long_text_multiline __________

self = <failure_demo.TestSpecialisedExplanations object at 0x29cee50>

    def test_eq_long_text_multiline(self):
        a = '1\n'*100 + 'a' + '2\n'*100
        b = '1\n'*100 + 'b' + '2\n'*100
>       assert a == b
E       assert '1\n1\n1\n1\n...n2\n2\n2\n2\n' == '1\n1\n1\n1\n1...n2\n2\n2\n2\n'
E         Skipping 190 identical leading characters in diff, use -v to show
E         Skipping 191 identical trailing characters in diff, use -v to show
E           1
E           1
E           1
E           1
E           1
E         - a2
E         + b2
E           2
E           2
E           2
E           2

failure_demo.py:58: AssertionError
_________________ TestSpecialisedExplanations.test_eq_list _________________

self = <failure_demo.TestSpecialisedExplanations object at 0x29c3810>

    def test_eq_list(self):
>       assert [0, 1, 2] == [0, 1, 3]
E       assert [0, 1, 2] == [0, 1, 3]
E         At index 2 diff: 2 != 3

failure_demo.py:61: AssertionError
______________ TestSpecialisedExplanations.test_eq_list_long _______________

self = <failure_demo.TestSpecialisedExplanations object at 0x29e50d0>

    def test_eq_list_long(self):
        a = [0]*100 + [1] + [3]*100
        b = [0]*100 + [2] + [3]*100
>       assert a == b
E       assert [0, 0, 0, 0, 0, 0, ...] == [0, 0, 0, 0, 0, 0, ...]
E         At index 100 diff: 1 != 2

failure_demo.py:66: AssertionError
_________________ TestSpecialisedExplanations.test_eq_dict _________________

self = <failure_demo.TestSpecialisedExplanations object at 0x29c5dd0>

    def test_eq_dict(self):
>       assert {'a': 0, 'b': 1, 'c': 0} == {'a': 0, 'b': 2, 'd': 0}
E       assert {'a': 0, 'b': 1, 'c': 0} == {'a': 0, 'b': 2, 'd': 0}
E         Omitting 1 identical items, use -v to show
E         Differing items:
E         {'b': 1} != {'b': 2}
E         Left contains more items:
E         {'c': 0}
E         Right contains more items:
E         {'d': 0}

failure_demo.py:69: AssertionError
_________________ TestSpecialisedExplanations.test_eq_set __________________

self = <failure_demo.TestSpecialisedExplanations object at 0x29e2690>

    def test_eq_set(self):
>       assert set([0, 10, 11, 12]) == set([0, 20, 21])
E       assert set([0, 10, 11, 12]) == set([0, 20, 21])
E         Extra items in the left set:
E         10
E         11
E         12
E         Extra items in the right set:
E         20
E         21

failure_demo.py:72: AssertionError
_____________ TestSpecialisedExplanations.test_eq_longer_list ______________

self = <failure_demo.TestSpecialisedExplanations object at 0x29ceb50>

    def test_eq_longer_list(self):
>       assert [1,2] == [1,2,3]
E       assert [1, 2] == [1, 2, 3]
E         Right contains more items, first extra item: 3

failure_demo.py:75: AssertionError
_________________ TestSpecialisedExplanations.test_in_list _________________

self = <failure_demo.TestSpecialisedExplanations object at 0x29c3050>

    def test_in_list(self):
>       assert 1 in [0, 2, 3, 4, 5]
E       assert 1 in [0, 2, 3, 4, 5]

failure_demo.py:78: AssertionError
__________ TestSpecialisedExplanations.test_not_in_text_multiline __________

self = <failure_demo.TestSpecialisedExplanations object at 0x29e5b10>

    def test_not_in_text_multiline(self):
        text = 'some multiline\ntext\nwhich\nincludes foo\nand a\ntail'
>       assert 'foo' not in text
E       assert 'foo' not in 'some multiline\ntext\nw...ncludes foo\nand a\ntail'
E         'foo' is contained here:
E           some multiline
E           text
E           which
E           includes foo
E         ?          +++
E           and a
E           tail

failure_demo.py:82: AssertionError
___________ TestSpecialisedExplanations.test_not_in_text_single ____________

self = <failure_demo.TestSpecialisedExplanations object at 0x29f1610>

    def test_not_in_text_single(self):
        text = 'single foo line'
>       assert 'foo' not in text
E       assert 'foo' not in 'single foo line'
E         'foo' is contained here:
E           single foo line
E         ?        +++

failure_demo.py:86: AssertionError
_________ TestSpecialisedExplanations.test_not_in_text_single_long _________

self = <failure_demo.TestSpecialisedExplanations object at 0x29cea50>

    def test_not_in_text_single_long(self):
        text = 'head ' * 50 + 'foo ' + 'tail ' * 20
>       assert 'foo' not in text
E       assert 'foo' not in 'head head head head hea...ail tail tail tail tail '
E         'foo' is contained here:
E           head head foo tail tail tail tail tail tail tail tail tail tail tail tail tail tail tail tail tail tail tail tail
E         ?           +++

failure_demo.py:90: AssertionError
______ TestSpecialisedExplanations.test_not_in_text_single_long_term _______

self = <failure_demo.TestSpecialisedExplanations object at 0x29e2a10>

    def test_not_in_text_single_long_term(self):
        text = 'head ' * 50 + 'f'*70 + 'tail ' * 20
>       assert 'f'*70 not in text
E       assert 'fffffffffff...ffffffffffff' not in 'head head he...l tail tail '
E         'ffffffffffffffffff...fffffffffffffffffff' is contained here:
E           head head fffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffftail tail tail tail tail tail tail tail tail tail tail tail tail tail tail tail tail tail tail tail
E         ?           ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

failure_demo.py:94: AssertionError
______________________________ test_attribute ______________________________

    def test_attribute():
        class Foo(object):
            b = 1
        i = Foo()
>       assert i.b == 2
E       assert 1 == 2
E        +  where 1 = <failure_demo.Foo object at 0x29c77d0>.b

failure_demo.py:101: AssertionError
_________________________ test_attribute_instance __________________________

    def test_attribute_instance():
        class Foo(object):
            b = 1
>       assert Foo().b == 2
E       assert 1 == 2
E        +  where 1 = <failure_demo.Foo object at 0x29e5f10>.b
E        +    where <failure_demo.Foo object at 0x29e5f10> = <class 'failure_demo.Foo'>()

failure_demo.py:107: AssertionError
__________________________ test_attribute_failure __________________________

    def test_attribute_failure():
        class Foo(object):
            def _get_b(self):
                raise Exception('Failed to get attrib')
            b = property(_get_b)
        i = Foo()
>       assert i.b == 2

failure_demo.py:116:
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

self = <failure_demo.Foo object at 0x29e6b10>

    def _get_b(self):
>       raise Exception('Failed to get attrib')
E       Exception: Failed to get attrib

failure_demo.py:113: Exception
_________________________ test_attribute_multiple __________________________

    def test_attribute_multiple():
        class Foo(object):
            b = 1
        class Bar(object):
            b = 2
>       assert Foo().b == Bar().b
E       assert 1 == 2
E        +  where 1 = <failure_demo.Foo object at 0x29c3b10>.b
E        +    where <failure_demo.Foo object at 0x29c3b10> = <class 'failure_demo.Foo'>()
E        +  and   2 = <failure_demo.Bar object at 0x29c3350>.b
E        +    where <failure_demo.Bar object at 0x29c3350> = <class 'failure_demo.Bar'>()

failure_demo.py:124: AssertionError
__________________________ TestRaises.test_raises __________________________

self = <failure_demo.TestRaises instance at 0x2aec878>

    def test_raises(self):
        s = 'qwe'
>       raises(TypeError, "int(s)")

failure_demo.py:133:
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

>   int(s)
E   ValueError: invalid literal for int() with base 10: 'qwe'

<0-codegen /home/hpk/p/pytest/.tox/regen/local/lib/python2.7/site-packages/_pytest/python.py:999>:1: ValueError
______________________ TestRaises.test_raises_doesnt _______________________

self = <failure_demo.TestRaises instance at 0x2aafef0>

    def test_raises_doesnt(self):
>       raises(IOError, "int('3')")
E       Failed: DID NOT RAISE

failure_demo.py:136: Failed
__________________________ TestRaises.test_raise ___________________________

self = <failure_demo.TestRaises instance at 0x2ae5758>

    def test_raise(self):
>       raise ValueError("demo error")
E       ValueError: demo error

failure_demo.py:139: ValueError
________________________ TestRaises.test_tupleerror ________________________

self = <failure_demo.TestRaises instance at 0x29cf4d0>

    def test_tupleerror(self):
>       a,b = [1]
E       ValueError: need more than 1 value to unpack

failure_demo.py:142: ValueError
______ TestRaises.test_reinterpret_fails_with_print_for_the_fun_of_it ______

self = <failure_demo.TestRaises instance at 0x29cf9e0>

    def test_reinterpret_fails_with_print_for_the_fun_of_it(self):
        l = [1,2,3]
        print ("l is %r" % l)
>       a,b = l.pop()
E       TypeError: 'int' object is not iterable

failure_demo.py:147: TypeError
----------------------------- Captured stdout ------------------------------
l is [1, 2, 3]
________________________ TestRaises.test_some_error ________________________

self = <failure_demo.TestRaises instance at 0x29d9ea8>

    def test_some_error(self):
>       if namenotexi:
E       NameError: global name 'namenotexi' is not defined

failure_demo.py:150: NameError
____________________ test_dynamic_compile_shows_nicely _____________________

    def test_dynamic_compile_shows_nicely():
        src = 'def foo():\n assert 1 == 0\n'
        name = 'abc-123'
        module = py.std.imp.new_module(name)
        code = py.code.compile(src, name, 'exec')
        py.builtin.exec_(code, module.__dict__)
        py.std.sys.modules[name] = module
>       module.foo()

failure_demo.py:165:
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

    def foo():
>    assert 1 == 0
E    assert 1 == 0

<2-codegen 'abc-123' /home/hpk/p/pytest/doc/en/example/assertion/failure_demo.py:162>:2: AssertionError
____________________ TestMoreErrors.test_complex_error _____________________

self = <failure_demo.TestMoreErrors instance at 0x29ca8c0>

    def test_complex_error(self):
        def f():
            return 44
        def g():
            return 43
>       somefunc(f(), g())

failure_demo.py:175:
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

x = 44, y = 43

    def somefunc(x,y):
>       otherfunc(x,y)

failure_demo.py:8:
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

a = 44, b = 43

    def otherfunc(a,b):
>       assert a==b
E       assert 44 == 43

failure_demo.py:5: AssertionError
___________________ TestMoreErrors.test_z1_unpack_error ____________________

self = <failure_demo.TestMoreErrors instance at 0x2ae2ea8>

    def test_z1_unpack_error(self):
        l = []
>       a,b  = l
E       ValueError: need more than 0 values to unpack

failure_demo.py:179: ValueError
____________________ TestMoreErrors.test_z2_type_error _____________________

self = <failure_demo.TestMoreErrors instance at 0x29da518>

    def test_z2_type_error(self):
        l = 3
>       a,b  = l
E       TypeError: 'int' object is not iterable

failure_demo.py:183: TypeError
______________________ TestMoreErrors.test_startswith ______________________

self = <failure_demo.TestMoreErrors instance at 0x29b8440>

    def test_startswith(self):
        s = "123"
        g = "456"
>       assert s.startswith(g)
E       assert <built-in method startswith of str object at 0x29ea328>('456')
E        +  where <built-in method startswith of str object at 0x29ea328> = '123'.startswith

failure_demo.py:188: AssertionError
__________________ TestMoreErrors.test_startswith_nested ___________________

self = <failure_demo.TestMoreErrors instance at 0x2ae4e18>

    def test_startswith_nested(self):
        def f():
            return "123"
        def g():
            return "456"
>       assert f().startswith(g())
E       assert <built-in method startswith of str object at 0x29ea328>('456')
E        +  where <built-in method startswith of str object at 0x29ea328> = '123'.startswith
E        +    where '123' = <function f at 0x29595f0>()
E        +  and   '456' = <function g at 0x2ab5320>()

failure_demo.py:195: AssertionError
_____________________ TestMoreErrors.test_global_func ______________________

self = <failure_demo.TestMoreErrors instance at 0x2abf320>

    def test_global_func(self):
>       assert isinstance(globf(42), float)
E       assert isinstance(43, float)
E        +  where 43 = globf(42)

failure_demo.py:198: AssertionError
_______________________ TestMoreErrors.test_instance _______________________

self = <failure_demo.TestMoreErrors instance at 0x2aaf050>

    def test_instance(self):
        self.x = 6*7
>       assert self.x != 42
E       assert 42 != 42
E        +  where 42 = <failure_demo.TestMoreErrors instance at 0x2aaf050>.x

failure_demo.py:202: AssertionError
_______________________ TestMoreErrors.test_compare ________________________

self = <failure_demo.TestMoreErrors instance at 0x2aedbd8>

    def test_compare(self):
>       assert globf(10) < 5
E       assert 11 < 5
E        +  where 11 = globf(10)

failure_demo.py:205: AssertionError
_____________________ TestMoreErrors.test_try_finally ______________________

self = <failure_demo.TestMoreErrors instance at 0x29f2098>

    def test_try_finally(self):
        x = 1
        try:
>           assert x == 0
E           assert 1 == 0

failure_demo.py:210: AssertionError
======================== 39 failed in 0.20 seconds =========================