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Python unittest Assert Methods

02 Jan 2020 | programming

This post contains the assert methods listed in the documentation for Python unittest module. It’s a quick reference so I don’t have to scroll through the docs to find a specific statement.

Commonly Used

Method Checks that
assertEqual(a, b) a == b
assertNotEqual(a, b) a != b
assertTrue(x) bool(x) is True
assertFalse(x) bool(x) is False
assertIs(a, b) a is b
assertIsNot(a, b) a is not b
assertIsNone(x) x is None
assertIsNotNone(x) x is not None
assertIn(a, b) a in b
assertNotIn(a, b) a not in b
assertIsInstance(a, b) isinstance(a, b)
assertNotIsInstance(a, b) not isinstance(a, b)

Exceptions, Warnings, and Logs

Method Checks that
assertRaises(exc, fun, *args, **kwds) fun(*args, **kwds) raises exc
assertRaisesRegex(exc, r, fun, *args, **kwds) fun(*args, **kwds) raises exc
and the message matches regex r
assertWarns(warn, fun, *args, **kwds) fun(*args, **kwds) raises warn
assertWarnsRegex(warn, r, fun, *args, **kwds) fun(*args, **kwds) raises warn
and the message matches regex r
assertLogs(logger, level) The with block logs on logger with
minimum level

Specific Checks

Method Checks that
assertAlmostEqual(a, b) round(a-b, 7) == 0
assertNotAlmostEqual(a, b) round(a-b, 7) != 0
assertGreater(a, b) a > b
assertGreaterEqual(a, b) a >= b
assertLess(a, b) a < b
assertLessEqual(a, b) a <= b
assertRegex(s, r) r.search(s)
assertNotRegex(s, r) not r.search(s)
assertCountEqual(a, b) a and b have the same elements in the
same number, regardless of their order

Type-Specific

Method Used to Compare
assertMultiLineEqual(a, b) strings
assertSequenceEqual(a, b) sequences
assertListEqual(a, b) lists
assertTupleEqual(a, b) tuples
assertSetEqual(a, b) sets or frozensets
assertDictEqual(a, b) dicts

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