Changed in version 3.1: Added the ability to use assertRaises() as a context manager.

November 16, 2016 - import unittest def func(): raise Exception('lets see if this works') class ExampleTest(unittest.TestCase): def test_error(self): self.assertRaises(Exception, lambda:func()) if __name__=='__main__': unittest.main() But lambda is a whole new monster on its own. It doesn't seem to be the right tool to use just as a wrapper for the function. This is a much more appropriate and pythonic way of using assertRaises.

In Python’s unittest framework, the assertRaises TestCase method is used to test that a specific exception is raised.

July 15, 2025 - assertRaises(exception) Make a function call that should raise the exception with a context. The context manager will caught an exception and store it in the object in its exception attribute.

May 16, 2026 - import dum_function as df # import function module import unittest class Test(unittest.TestCase): """ The class inherits from unittest """ def setUp(self): """ This method is called before each test """ self.false_int = "A" def tearDown(self): """ This method is called after each test """ pass #--- ## TESTS def test_square_value(self): # assertRaises(excClass, callableObj) prototype self.assertRaises(TypeError, df.square_value(self.false_int)) if name == "main": unittest.main()

April 29, 2024 - Language: Python Filename: test_game.py · import unittest from game import rock_paper_scissors class TestRockPaperScissors(unittest.TestCase): def test_out_of_range(self): with self.assertRaises(ValueError): rock_paper_scissors(42) def test_rock(self): self.assertEqual(rock_paper_scissors(0), "rock") def test_paper(self): self.assertEqual(rock_paper_scissors(1), "paper") def test_scissors(self): self.assertEqual(rock_paper_scissors(2), "scissors") if __name__ == "__main__": unittest.main() The first test provides a way to check whether the function validates the input argument, which must be a number between 0 and 2.

with self.assertRaises(SomeException) as cm: do_something() the_exception = cm.exception self.assertEqual(the_exception.error_code, 3)

October 24, 2018 - Then, we define three methods, the names for which begin with ‘test’: ... assertRaises()- Tests that Python raises an exception when we call the callable with positional/ keyword arguments we also passed to this method.

assertRaises(exception, callable, *args, **kwds) Test that an exception is raised when callable is called with any positional or keyword arguments that are also passed to assertRaises().

pytest allows you to use the standard Python assert for verifying expectations and values in Python tests.

March 9, 2025 - There are two helpers in unittest.TestCase for asserting that exceptions are raised and properties of them: assertRaises checks that an exception is raised and asserts its type assertRaisesRegex checks that an exception is raised and matches ...

July 15, 2025 - assertTrue() in Python is a unittest library function that is used in unit testing to compare test value with true. This function will take two parameters as input and return a boolean value depending upon the assert condition.

Python testing framework uses Python's built-in assert() function which tests a particular condition. If the assertion fails, an AssertionError will be raised. The testing framework will then identify the test as Failure.

Code Review Doctor suggests a fix if your code does not follows Python testing best practices.

Test that an exception is raised when callable is called with any positional or keyword arguments that are also passed to assertRaises(). The test passes if exception is raised, is an error if another exception is raised, or fails if no exception is raised.

August 25, 2026 - Python’s unittest framework provides dedicated assertion methods instead of relying only on the assert statement. import unittest class TestMath(unittest.TestCase): def test_multiply(self): self.assertEqual(2 * 3, 6) self.assertGreater(10, 5) self.assertIsNone(None) Output – · Methods such as assertEqual(), assertTrue(), assertIn(), and assertRaises() make the expected relationship explicit and provide failure information when a test does not pass.

Python has built-in assert statement to use assertion condition in the program. assert statement has a condition or expression which is supposed to be always true.

Python unittest Assertions cheat sheet. GitHub Gist: instantly share code, notes, and snippets.

All the assert methods except assertRaises() and assertRaisesRegexp() accept a msg argument that, if specified, is used as the error message on failure.