bin:testing progprim$ ls -l
total 24
drwxr-xr-x  5 progprim  staff   170 29 Sep 11:43 __pycache__
-rw-r--r--  1 progprim  staff  1236 29 Sep 11:37 factorial.py
-rw-r--r--  1 progprim  staff  1045 20 Sep 08:56 mixstrings-pytest.py
-rw-r--r--  1 progprim  staff  1080 29 Sep 14:24 mixstrings.py
bin:testing progprim$ less mixstrings.py 
bin:testing progprim$ python mixstrings.py 
bin:testing progprim$ python mixstrings.py 
Traceback (most recent call last):
  File "mixstrings.py", line 39, in <module>
    test_mixstrings_basics()
  File "mixstrings.py", line 26, in test_mixstrings_basics
    assert mixstrings("hello", "world") == "hweolrllod"
AssertionError
bin:testing progprim$ py.test mixstrings.py 
============================= test session starts ==============================
platform darwin -- Python 3.5.2, pytest-2.9.2, py-1.4.31, pluggy-0.3.1
rootdir: /Users/progprim/Desktop/code/testing, inifile: 
collected 3 items 

mixstrings.py ...

=========================== 3 passed in 0.01 seconds ===========================
bin:testing progprim$ py.test -v mixstrings.py 
============================= test session starts ==============================
platform darwin -- Python 3.5.2, pytest-2.9.2, py-1.4.31, pluggy-0.3.1 -- /Users/progprim/anaconda/bin/python
cachedir: .cache
rootdir: /Users/progprim/Desktop/code/testing, inifile: 
collected 3 items 

mixstrings.py::test_mixstrings_basics PASSED
mixstrings.py::test_mixstrings_empty PASSED
mixstrings.py::test_mixstrings_different_length PASSED

=========================== 3 passed in 0.01 seconds ===========================
bin:testing progprim$ py.test -v mixstrings.py 
============================= test session starts ==============================
platform darwin -- Python 3.5.2, pytest-2.9.2, py-1.4.31, pluggy-0.3.1 -- /Users/progprim/anaconda/bin/python
cachedir: .cache
rootdir: /Users/progprim/Desktop/code/testing, inifile: 
collected 3 items 

mixstrings.py::test_mixstrings_basics FAILED
mixstrings.py::test_mixstrings_empty FAILED
mixstrings.py::test_mixstrings_different_length FAILED

=================================== FAILURES ===================================
____________________________ test_mixstrings_basics ____________________________

    def test_mixstrings_basics():
>       assert mixstrings("hello", "world") == "hweolrllod"
E       assert 'bhweolrllod' == 'hweolrllod'
E         - bhweolrllod
E         ? -
E         + hweolrllod

mixstrings.py:26: AssertionError
____________________________ test_mixstrings_empty _____________________________

    def test_mixstrings_empty():
>       assert mixstrings("", "") == ""
E       assert 'b' == ''
E         - b

mixstrings.py:31: AssertionError
_______________________ test_mixstrings_different_length _______________________

    def test_mixstrings_different_length():
>       assert mixstrings("12345", "123") == "112233"
E       assert 'b112233' == '112233'
E         - b112233
E         ? -
E         + 112233

mixstrings.py:35: AssertionError
=========================== 3 failed in 0.06 seconds ===========================
bin:testing progprim$ py.test -v mixstrings.py 
============================= test session starts ==============================
platform darwin -- Python 3.5.2, pytest-2.9.2, py-1.4.31, pluggy-0.3.1 -- /Users/progprim/anaconda/bin/python
cachedir: .cache
rootdir: /Users/progprim/Desktop/code/testing, inifile: 
collected 3 items 

mixstrings.py::test_mixstrings_basics PASSED
mixstrings.py::test_mixstrings_empty PASSED
mixstrings.py::test_mixstrings_different_length PASSED

=========================== 3 passed in 0.02 seconds ===========================
bin:testing progprim$ py.test -v mixstrings.py 
============================= test session starts ==============================
platform darwin -- Python 3.5.2, pytest-2.9.2, py-1.4.31, pluggy-0.3.1 -- /Users/progprim/anaconda/bin/python
cachedir: .cache
rootdir: /Users/progprim/Desktop/code/testing, inifile: 
collected 3 items 

mixstrings.py::test_mixstrings_basics PASSED
mixstrings.py::test_mixstrings_empty PASSED
mixstrings.py::test_mixstrings_different_length FAILED

=================================== FAILURES ===================================
_______________________ test_mixstrings_different_length _______________________

    def test_mixstrings_different_length():
        assert mixstrings("12345", "123") == "112233"
>       assert mixstrings("", "hello") == "hello"
E       assert '' == 'hello'
E         + hello

mixstrings.py:36: AssertionError
====================== 1 failed, 2 passed in 0.02 seconds ======================
bin:testing progprim$ python mixstrings.py 
============================= test session starts ==============================
platform darwin -- Python 3.5.2, pytest-2.9.2, py-1.4.31, pluggy-0.3.1 -- /Users/progprim/anaconda/bin/python
cachedir: .cache
rootdir: /Users/progprim/Desktop/code/testing, inifile: 
collected 3 items 

mixstrings.py::test_mixstrings_basics PASSED
mixstrings.py::test_mixstrings_empty PASSED
mixstrings.py::test_mixstrings_different_length PASSED

=========================== 3 passed in 0.01 seconds ===========================
bin:testing progprim$ py.test -v factorial.py 
============================= test session starts ==============================
platform darwin -- Python 3.5.2, pytest-2.9.2, py-1.4.31, pluggy-0.3.1 -- /Users/progprim/anaconda/bin/python
cachedir: .cache
rootdir: /Users/progprim/Desktop/code/testing, inifile: 
collected 4 items 

factorial.py::test_basics PASSED
factorial.py::test_against_standard_lib PASSED
factorial.py::test_negative_number_raises_error PASSED
factorial.py::test_noninteger_number_raises_error PASSED

=========================== 4 passed in 0.01 seconds ===========================
bin:testing progprim$ py.test -v factorial.py 
============================= test session starts ==============================
platform darwin -- Python 3.5.2, pytest-2.9.2, py-1.4.31, pluggy-0.3.1 -- /Users/progprim/anaconda/bin/python
cachedir: .cache
rootdir: /Users/progprim/Desktop/code/testing, inifile: 
collected 4 items 

factorial.py::test_basics PASSED
factorial.py::test_against_standard_lib PASSED
factorial.py::test_negative_number_raises_error PASSED
factorial.py::test_noninteger_number_raises_error FAILED

=================================== FAILURES ===================================
_____________________ test_noninteger_number_raises_error ______________________

    def test_noninteger_number_raises_error():
        with pytest.raises(ValueError):
            # factorial(0.5)
>           pass
E           Failed: DID NOT RAISE

factorial.py:51: Failed
====================== 1 failed, 3 passed in 0.01 seconds ======================
bin:testing progprim$ ls 
__pycache__		mixstrings-pytest.py
factorial.py		mixstrings.py
bin:testing progprim$ py.test -v factorial.py mixstrings.py 
============================= test session starts ==============================
platform darwin -- Python 3.5.2, pytest-2.9.2, py-1.4.31, pluggy-0.3.1 -- /Users/progprim/anaconda/bin/python
cachedir: .cache
rootdir: /Users/progprim/Desktop/code/testing, inifile: 
collected 7 items 

factorial.py::test_basics PASSED
factorial.py::test_against_standard_lib PASSED
factorial.py::test_negative_number_raises_error PASSED
factorial.py::test_noninteger_number_raises_error FAILED
mixstrings.py::test_mixstrings_basics PASSED
mixstrings.py::test_mixstrings_empty PASSED
mixstrings.py::test_mixstrings_different_length PASSED

=================================== FAILURES ===================================
_____________________ test_noninteger_number_raises_error ______________________

    def test_noninteger_number_raises_error():
        with pytest.raises(ValueError):
            # factorial(0.5)
>           pass
E           Failed: DID NOT RAISE

factorial.py:51: Failed
====================== 1 failed, 6 passed in 0.01 seconds ======================
bin:testing progprim$ py.test -v factorial.py mixstrings.py 
============================= test session starts ==============================
platform darwin -- Python 3.5.2, pytest-2.9.2, py-1.4.31, pluggy-0.3.1 -- /Users/progprim/anaconda/bin/python
cachedir: .cache
rootdir: /Users/progprim/Desktop/code/testing, inifile: 
collected 7 items 

factorial.py::test_basics PASSED
factorial.py::test_against_standard_lib PASSED
factorial.py::test_negative_number_raises_error PASSED
factorial.py::test_noninteger_number_raises_error PASSED
mixstrings.py::test_mixstrings_basics PASSED
mixstrings.py::test_mixstrings_empty PASSED
mixstrings.py::test_mixstrings_different_length PASSED

=========================== 7 passed in 0.02 seconds ===========================
bin:testing progprim$ ls -l
total 32
drwxr-xr-x  5 progprim  staff   170 29 Sep 14:39 __pycache__
-rw-r--r--  1 progprim  staff   675 29 Sep 14:40 factorial.py
-rw-r--r--  1 progprim  staff  1045 20 Sep 08:56 mixstrings-pytest.py
-rw-r--r--  1 progprim  staff  1136 29 Sep 14:31 mixstrings.py
-rw-r--r--  1 progprim  staff   719 29 Sep 14:40 test_factorial.py
bin:testing progprim$ py.test -v .
============================= test session starts ==============================
platform darwin -- Python 3.5.2, pytest-2.9.2, py-1.4.31, pluggy-0.3.1 -- /Users/progprim/anaconda/bin/python
cachedir: .cache
rootdir: /Users/progprim/Desktop/code/testing, inifile: 
collected 4 items 

test_factorial.py::test_basics PASSED
test_factorial.py::test_against_standard_lib FAILED
test_factorial.py::test_negative_number_raises_error FAILED
test_factorial.py::test_noninteger_number_raises_error FAILED

=================================== FAILURES ===================================
__________________________ test_against_standard_lib ___________________________

    def test_against_standard_lib():
        for i in range(20):
>           assert math.factorial(i) == factorial(i)
E           NameError: name 'math' is not defined

test_factorial.py:17: NameError
______________________ test_negative_number_raises_error _______________________

    def test_negative_number_raises_error():
>       with pytest.raises(ValueError):    # this will pass if
E       NameError: name 'pytest' is not defined

test_factorial.py:21: NameError
_____________________ test_noninteger_number_raises_error ______________________

    def test_noninteger_number_raises_error():
>       with pytest.raises(ValueError):
E       NameError: name 'pytest' is not defined

test_factorial.py:26: NameError
====================== 3 failed, 1 passed in 0.02 seconds ======================
bin:testing progprim$ py.test -v .
============================= test session starts ==============================
platform darwin -- Python 3.5.2, pytest-2.9.2, py-1.4.31, pluggy-0.3.1 -- /Users/progprim/anaconda/bin/python
cachedir: .cache
rootdir: /Users/progprim/Desktop/code/testing, inifile: 
collected 4 items 

test_factorial.py::test_basics PASSED
test_factorial.py::test_against_standard_lib PASSED
test_factorial.py::test_negative_number_raises_error PASSED
test_factorial.py::test_noninteger_number_raises_error PASSED

=========================== 4 passed in 0.01 seconds ===========================
bin:testing progprim$ dir
-bash: dir: command not found
bin:testing progprim$ ls 
__pycache__		mixstrings-pytest.py	test_factorial.py
factorial.py		mixstrings.py
bin:testing progprim$ py.test -v test_factorial.py 
============================= test session starts ==============================
platform darwin -- Python 3.5.2, pytest-2.9.2, py-1.4.31, pluggy-0.3.1 -- /Users/progprim/anaconda/bin/python
cachedir: .cache
rootdir: /Users/progprim/Desktop/code/testing, inifile: 
collected 4 items 

test_factorial.py::test_basics PASSED
test_factorial.py::test_against_standard_lib PASSED
test_factorial.py::test_negative_number_raises_error PASSED
test_factorial.py::test_noninteger_number_raises_error xfail

===================== 3 passed, 1 xfailed in 0.02 seconds ======================
bin:testing progprim$ py.test -v test_factorial.py 
============================= test session starts ==============================
platform darwin -- Python 3.5.2, pytest-2.9.2, py-1.4.31, pluggy-0.3.1 -- /Users/progprim/anaconda/bin/python
cachedir: .cache
rootdir: /Users/progprim/Desktop/code/testing, inifile: 
collected 4 items 

test_factorial.py::test_basics PASSED
test_factorial.py::test_against_standard_lib PASSED
test_factorial.py::test_negative_number_raises_error PASSED
test_factorial.py::test_noninteger_number_raises_error XPASS

===================== 3 passed, 1 xpassed in 0.01 seconds ======================
bin:testing progprim$