Python Unit Test Automation

Listing 3-18.  test_module12.py
import sys
import unittest
class TestClass13(unittest.TestCase):
    @unittest.skip("demonstrating unconditional skipping")
    def test_case01(self):
        self.fail("FATAL")
    @unittest.skipUnless(sys.platform.startswith("win"), "requires Windows")
    def test_case02(self):
        # Windows specific testing code
        pass
    @unittest.skipUnless(sys.platform.startswith("linux"), "requires Linux")
    def test_case03(self):
        # Linux specific testing code
        pass
When you run the code in Listing 
3-18
 on the Linux platform, the output is as 
follows:
test_case01 (test_module12.TestClass13) ... skipped 'demonstrating 
unconditional skipping'
test_case02 (test_module12.TestClass13) ... skipped 'requires Windows'
test_case03 (test_module12.TestClass13) ... ok
----------------------------------------------------------------------
Ran 3 tests in 0.003s
OK (skipped=2)
When you run the code in Listing 
3-18
 on the Windows platform, the output is as 
follows:
test_case01 (test_module12.TestClass13) ... skipped 'demonstrating 
unconditional skipping'

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Chapter 3 
■
 Unittest
59
test_case02 (test_module12.TestClass13) ... ok
test_case03 (test_module12.TestClass13) ... skipped 
'requires Linux'
----------------------------------------------------------------------
Ran 3 tests in 0.003s
OK (skipped=2)
As you can see, the code skips the test cases based on the OS where it runs. This trick 
is very useful for running platform-specific test cases.
You can also skip entire test classes in a test module using the unittest.
skip(reason) decorator.
Exceptions in the Test Case
When an exception is raised in a test case, the test case fails. The code shown in Listing 
3-19
 
will raise an exception explicitly.