Python Unit Test Automation

Listing 4-9.  test_module07.py
from nose.tools import raises
@raises(TypeError, ValueError)
def test_case01():
    raise TypeError("This test passes")
@raises(Exception)
def test_case02():
    pass

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Chapter 4 
■
 nose and nose2
79
The output is as follows:
In setUpPackage()...
test.test_module07.test_case01 ... ok
test.test_module07.test_case02 ... FAIL
In tearDownPackage()...
======================================================================
FAIL: test.test_module07.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 "/usr/local/lib/python3.4/dist-packages/nose/tools/nontrivial.py", 
line 67, in newfunc
    raise AssertionError(message)
AssertionError: test_case02() did not raise Exception
----------------------------------------------------------------------
Ran 2 tests in 0.012s
FAILED (failures=1)
As you can see, test_case02() fails as it does not raise a exception when it is 
supposed to. You can cleverly use this to write negative test cases.
The @timed() decorator
If you are using a timed decorator with the test, then the test must finish within the time 
mentioned in the @timed() decorator to pass. The code in Listing 
4-10
 demonstrates that idea.