96 lines
2.7 KiB
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96 lines
2.7 KiB
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=====================================
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OpenStack Nova Testing Infrastructure
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=====================================
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This README file attempts to provide current and prospective contributors with
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everything they need to know in order to start creating unit tests for nova.
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Note: the content for the rest of this file will be added as the work items in
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the following blueprint are completed:
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https://blueprints.launchpad.net/nova/+spec/consolidate-testing-infrastructure
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Test Types: Unit vs. Functional vs. Integration
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-----------------------------------------------
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TBD
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Writing Unit Tests
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------------------
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TBD
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Using Fakes
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~~~~~~~~~~~
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TBD
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test.TestCase
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-------------
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The TestCase class from nova.test (generally imported as test) will
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automatically manage self.stubs using the stubout module and self.mox
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using the mox module during the setUp step. They will automatically
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verify and clean up during the tearDown step.
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If using test.TestCase, calling the super class setUp is required and
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calling the super class tearDown is required to be last if tearDown
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is overridden.
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Writing Functional Tests
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------------------------
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TBD
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Writing Integration Tests
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-------------------------
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TBD
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Tests and Exceptions
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--------------------
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A properly written test asserts that particular behavior occurs. This can
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be a success condition or a failure condition, including an exception.
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When asserting that a particular exception is raised, the most specific
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exception possible should be used.
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In particular, testing for Exception being raised is almost always a
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mistake since it will match (almost) every exception, even those
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unrelated to the exception intended to be tested.
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This applies to catching exceptions manually with a try/except block,
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or using assertRaises().
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Example::
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self.assertRaises(exception.InstanceNotFound, db.instance_get_by_uuid,
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elevated, instance_uuid)
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If a stubbed function/method needs a generic exception for testing
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purposes, test.TestingException is available.
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Example::
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def stubbed_method(self):
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raise test.TestingException()
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self.stubs.Set(cls, 'inner_method', stubbed_method)
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obj = cls()
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self.assertRaises(test.TestingException, obj.outer_method)
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Stubbing and Mocking
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--------------------
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Whenever possible, tests SHOULD NOT stub and mock out the same function.
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If it's unavoidable, tests SHOULD define stubs before mocks since the
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`TestCase` cleanup routine will un-mock before un-stubbing. Doing otherwise
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results in a test that leaks stubbed functions, causing hard-to-debug
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interference between tests [1]_.
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If a mock must take place before a stub, any stubs after the mock call MUST be
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manually unset using `self.cleanUp` calls within the test.
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.. [1] https://bugs.launchpad.net/nova/+bug/1180671
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