Python Unit Test Automation

Listing 4-7.  test_module05.py
from nose.tools import assert_equals
def test_case01():
    print("In test_case01()...")
    assert 2+2 == 5
def test_case02():
    print("In test_case02()...")
    assert_equals(2+2, 5)
Run the code in Listing 
4-7
. The following shows the output:
In setUpPackage()...
test.test_module05.test_case01 ... In test_case01()...
FAIL
test.test_module05.test_case02 ... In test_case02()...
FAIL
In tearDownPackage()...
======================================================================
FAIL: test.test_module05.test_case01
----------------------------------------------------------------------
Traceback (most recent call last):
   File "/usr/local/lib/python3.4/dist-packages/nose/case.py", line 198,  
in runTest
    self.test(*self.arg)
   File "/home/pi/book/code/chapter04/test/test_module05.py", line 6,  
in test_case01
    assert 2+2 == 5
AssertionError
======================================================================
FAIL: test.test_module05.test_case02
----------------------------------------------------------------------
Traceback (most recent call last):
   File "/usr/local/lib/python3.4/dist-packages/nose/case.py", line 198,  
in runTest
    self.test(*self.arg)
   File "/home/pi/book/code/chapter04/test/test_module05.py", line 11,  
in test_case02
    assert_equals(2+2, 5)
AssertionError: 4 != 5
----------------------------------------------------------------------
Ran 2 tests in 0.013s
FAILED (failures=2)

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Chapter 4 
■
 nose and nose2
77
Both the test cases failed due to incorrect test inputs. Note the difference between the logs 
printed by these test methods. In test_case02(), you get more information about the 
cause of the failure, as you are using nose’s assert_equals() method.
Testing Tools
nose.tools has a few methods and decorators that come in very handy while you’re 
automating tests.
This section looks at a few of those testing tools.
ok_ and eq_
ok_ and eq_ are shorthand for assert and assert_equals(), respectively. They also come 
with a parameter for an error message when the test case fails. The code in Listing 
4-8
 
demonstrates this.