{"id":3629,"date":"2022-07-04T00:18:34","date_gmt":"2022-07-04T00:18:34","guid":{"rendered":"https:\/\/www.pythontutorial.net\/?page_id=3629"},"modified":"2022-07-09T07:31:33","modified_gmt":"2022-07-09T07:31:33","slug":"python-unittest-assert","status":"publish","type":"page","link":"https:\/\/www.pythontutorial.net\/python-unit-testing\/python-unittest-assert\/","title":{"rendered":"Python Unittest Assert Methods"},"content":{"rendered":"\n

Summary<\/strong>: in this tutorial, you’ll learn the overview of the Python unittest<\/code> assert methods to perform unit testing.<\/p>\n\n\n\n

Introduction to Python unittest assert methods #<\/a><\/h2>\n\n\n\n

The TestCase<\/code> class of the unittest<\/a> module provides you with a large number of assert methods to test. The following table shows the most commonly used assert methods:<\/p>\n\n\n\n

Method<\/th>Checks that<\/th><\/tr><\/thead>
assertEqual(x,\u00a0y, msg=None)<\/a><\/code><\/td>x == y<\/code><\/td><\/tr>
assertNotEqual(x,y,msg=None)<\/a><\/code><\/td>x != y<\/code><\/td><\/tr>
assertTrue(x, msg=None)<\/a><\/code><\/td>bool(x) is True<\/code><\/td><\/tr>
assertFalse(x, msg=None)<\/a><\/code><\/td>bool(x) is False<\/code><\/td><\/tr>
assertIs(x,\u00a0y , msg=None)<\/a><\/code><\/td>x is y<\/code><\/td><\/tr>
assertIsNot(x,\u00a0y, msg=None)<\/a><\/code><\/td>x is not <\/code>y<\/td><\/tr>
assertIsNone(x, msg=None)<\/a><\/code><\/td>x is None<\/code><\/td><\/tr>
assertIsNotNone(x , msg=None)<\/a><\/code><\/td>x is not None<\/code><\/td><\/tr>
assertIn(x,\u00a0y, msg=None)<\/a><\/code><\/td>x in <\/code>y<\/td><\/tr>
assertNotIn(x,\u00a0y, msg=None)<\/a><\/code><\/td>x not in <\/code>y<\/td><\/tr>
assertIsInstance(x,\u00a0y, msg=None)<\/a><\/code><\/td>isinstance(x, y)<\/code><\/td><\/tr>
assertNotIsInstance(x,\u00a0y, msg=None)<\/a><\/code><\/td>not isinstance(x, y)<\/code><\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n

All of these methods have an optional msg<\/code> parameter whose type is a string. The msg<\/code> will be displayed in the test result if the test fails.<\/p>\n\n\n\n

The following assert methods check the exceptions, warnings, and log messages:<\/p>\n\n\n\n

Method<\/th>Checks that<\/th><\/tr><\/thead>
assertRaises(exc, fun, *args, **kwds)<\/code><\/td>fun(*args, **kwds)<\/code> raises exc<\/em><\/td><\/tr>
assertRaisesRegex(exc, r, fun, *args, **kwds)<\/code><\/td>fun(*args, **kwds)<\/code> raises exc<\/em> and the message matches regex r<\/em><\/td><\/tr>
assertWarns(warn, fun, *args, **kwds)<\/code><\/td>fun(*args, **kwds)<\/code> raises warn<\/em><\/td><\/tr>
assertWarnsRegex(warn, r, fun, *args, **kwds)<\/code><\/td>fun(*args, **kwds)<\/code> raises warn<\/em> and the message matches regex r<\/em><\/td><\/tr>
assertLogs(logger, level)<\/code><\/td>The with<\/code> block logs on logger<\/em> with a minimum level<\/em><\/td><\/tr>
assertNoLogs(logger, level)<\/code><\/td>The with<\/code> block does not log on logger<\/em> with a minimum level<\/em><\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n

The following table shows the assert methods that perform more specific checks:<\/p>\n\n\n\n

Method<\/th>Checks that<\/th><\/tr><\/thead>
assertAlmostEqual(x, y)<\/a><\/code><\/td>round(x-y, 7) == 0<\/code><\/td><\/tr>
assertNotAlmostEqual(x, y)<\/a><\/code><\/td>round(x-y, 7) != 0<\/code><\/td><\/tr>
assertGreater(x, y)<\/code><\/td>x > y<\/code><\/td><\/tr>
assertGreaterEqual(x, y)<\/code><\/td>x >= y<\/code><\/td><\/tr>
assertLess(x, y)<\/code><\/td>x < <\/code>y<\/td><\/tr>
assertLessEqual(x, y)<\/code><\/td>x <= <\/code>y<\/td><\/tr>
assertRegex(s, r)<\/code><\/td>r.search(s)<\/code><\/td><\/tr>
assertNotRegex(s, r)<\/code><\/td>not r.search(s)<\/code><\/td><\/tr>
assertCountEqual(x, y)<\/code><\/td>x<\/em> and y<\/em> have the same number of elements in the same number.<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n

In the next tutorials, you’ll learn about the unittest<\/code> assert methods in more detail and how to use them effectively.<\/p>\n

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