Testing

The Mojo CLI has a built-in test runner that can be used to test Mojo programs. The mojo test command recursively searches the test directory for any files with test in the filename. For example, given the following directory structure:

test/
  test_users_controller.mojo
  factories.mojo
  models/
    user_model_tests.mojo

The mojo CLI will search test_users_controller.mojo and user_model_tests.mojo for tests, but not factories.mojo.

Test functions

Test functions must be named test_* and take no arguments. Use def notation rather than fn notation. By definition, every test function should be capable of raising an error. So:

from testing import assert_equal


def test_foo():
    assert_equal(1, 1)

Not:

fn test_foo() raises:
    assert_equal(1, 1)

The testing module defines a set of test-related utilities.