rspec/rules/S5845/python/rule.adoc

Calling ``unittest`` methods ``assertEqual``, ``assertNotEqual``, ``assertIs`` or ``assertIsNot`` on objects of incompatible types will always fail or always succeed.

For methods ``assertEqual`` and ``assertNotEqual``, arguments' types are incompatible if:

    they are unrelated builtin types such as string and integer.
    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).

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.

== Noncompliant Code Example

----
import unittest
class A(): ...
class MyTest(unittest.TestCase):
  def test_something(self):
    a = A()
    mydict = {"x": a}
    self.assertEqual(a, "x")  # Noncompliant
    self.assertIs(a, "x")  # Noncompliant
----

== Compliant Solution

----
import unittest
class A(): ...
class MyTest(unittest.TestCase):
  def test_something(self):
    a = A()
    mydict = {"x": a}
    self.assertEqual(a, mydict["x"])  # OK
    self.assertIs(a, mydict["x"])  # OK
----

== See

* S2159 Silly equality checks should not be made
* S3403 Identity operators should not be used with dissimilar types