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10236.5.1
by Jeroen Vermeulen
Adding FakeMethod helper. |
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# Copyright 2010 Canonical Ltd. This software is licensed under the
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# GNU Affero General Public License version 3 (see the file LICENSE).
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11403.1.4
by Henning Eggers
Reformatted imports using format-imports script r32. |
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from unittest import ( |
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TestCase, |
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TestLoader, |
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)
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10236.5.1
by Jeroen Vermeulen
Adding FakeMethod helper. |
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from lp.testing.fakemethod import FakeMethod |
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class RealActualClass: |
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"""A class that's hard to test."""
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doing_impossible_stuff = False |
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doing_possible_stuff = False |
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def impossibleMethod(self): |
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"""A method that you can't afford to invoke in your test.
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This is the method you're going to want to avoid calling. The
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way to do that is to replace this method with a fake method.
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"""
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self.doing_impossible_stuff = True |
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10236.5.3
by Jeroen Vermeulen
Lint. |
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raise AssertionError("Trying to do impossible stuff.") |
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10236.5.1
by Jeroen Vermeulen
Adding FakeMethod helper. |
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def testableMethod(self): |
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"""This part of the class logic that you do want to exercise."""
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self.doing_possible_stuff = True |
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def doComplicatedThings(self, argument): |
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"""This is the top-level method you want to test.
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Unfortunately this invokes impossibleMethod, making it hard.
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"""
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self.impossibleMethod() |
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self.testableMethod() |
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return argument |
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class CustomException(Exception): |
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"""Some specific error that you want raised."""
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class TestFakeMethod(TestCase): |
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def test_fakeMethod(self): |
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# A class that you're testing can continue normally despite some
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# of its methods being stubbed.
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thing = RealActualClass() |
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thing.impossibleMethod = FakeMethod() |
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result = thing.doComplicatedThings(99) |
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self.assertEqual(99, result) |
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self.assertFalse(thing.doing_impossible_stuff) |
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self.assertTrue(thing.doing_possible_stuff) |
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def test_raiseFailure(self): |
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# A FakeMethod can raise an exception you specify.
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ouch = CustomException("Ouch!") |
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func = FakeMethod(failure=ouch) |
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self.assertRaises(CustomException, func) |
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def test_returnResult(self): |
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# A FakeMethod can return a value you specify.
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value = "Fixed return value." |
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func = FakeMethod(result=value) |
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self.assertEqual(value, func()) |
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def test_countCalls(self): |
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# A FakeMethod counts the number of times it's been invoked.
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func = FakeMethod() |
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for count in xrange(3): |
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self.assertEqual(count, func.call_count) |
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func() |
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self.assertEqual(count + 1, func.call_count) |
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def test_takeArguments(self): |
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# A FakeMethod invocation accepts any arguments it gets.
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func = FakeMethod() |
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func() |
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func(1) |
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func(2, kwarg=3) |
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self.assertEqual(3, func.call_count) |
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def test_suite(): |
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return TestLoader().loadTestsFromName(__name__) |