40 lines
1.3 KiB
Plaintext
40 lines
1.3 KiB
Plaintext
Calling ``unittest`` methods ``assertEqual``, ``assertNotEqual``, ``assertIs`` or ``assertIsNot`` on objects of incompatible types will always fail or always succeed.
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For methods ``assertEqual`` and ``assertNotEqual``, arguments' types are incompatible if:
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they are unrelated builtin types such as string and integer.
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they are instances of unrelated classes which do not implement ``\_\_eq\_\_`` or ``\_\_ne\_\_`` (if a class implements one of these methods it could compare to any other type it wants).
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As for methods ``assertIs`` and ``assertIsNot``, if arguments' types are different it is not possible for them to point to the same object, thus ``assertIs`` will always fail and ``assertIsNot`` will always succeed.
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== Noncompliant Code Example
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----
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import unittest
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class A(): ...
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class MyTest(unittest.TestCase):
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def test_something(self):
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a = A()
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mydict = {"x": a}
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self.assertEqual(a, "x") # Noncompliant
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self.assertIs(a, "x") # Noncompliant
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----
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== Compliant Solution
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----
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import unittest
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class A(): ...
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class MyTest(unittest.TestCase):
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def test_something(self):
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a = A()
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mydict = {"x": a}
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self.assertEqual(a, mydict["x"]) # OK
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self.assertIs(a, mydict["x"]) # OK
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----
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== See
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* S2159 Silly equality checks should not be made
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* S3403 Identity operators should not be used with dissimilar types
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