19 Matching Annotations
  1. Nov 2020
    1. Comparison between pytest and unittes test frameworks

      Detailed comparison table of pytest vs unittest modules (check below)

  2. Apr 2020
    1. For example, the test_decrement functions given earlier are failing because the assertion itself is faulty.

      Debugging tests themselves

      1. Set a breakpoint on the first line of the failing function (e.g. test_decrement)
      2. Click the "Debug Test" option above the function
      3. Open Debug Console and type: inc_dec.decrement(3) to see what is the actual output when we use x=3
      4. Stop the debugger and correct the tests
      5. Save the test file and run the tests again to look for a positive result
    2. Once VS Code recognizes tests, it provides several ways to run those tests

      After discovering tests, we can run them, for example, using CodeLens:

    3. You can trigger test discovery at any time using the Python: Discover Tests command.

      After using python.testing.autoTestDiscoverOnSaveEnabled, it'll be set to true and discovering tests whenever a test file is saved.

      If discovery succeeds, the status bar shows Run Tests instead:

    4. Testing in Python is disabled by default. To enable testing, use the Python: Configure Tests command on the Command Palette.

      Start testing in VS Code by using Python: Configure Tests (it automatically chooses one testing framework and disables the rest).

      Otherwise, you can configure tests manually by setting only one of the following to True:

      • python.testing.unittestEnabled
      • python.testing.pytestEnabled
      • python.testing.nosetestsEnabled
    5. python.testing.unittestArgs: Looks for any Python (.py) file with "test" in the name in the top-level project folder.

      Default behaviour of test discovery by unittest framework

    6. Create a file named test_unittest.py that contains a test class with two test methods

      Sample test file using unittest framework. inc_dec is the file that's being tested:

      import inc_dec    # The code to test
      import unittest   # The test framework
      class Test_TestIncrementDecrement(unittest.TestCase):
          def test_increment(self):
              self.assertEqual(inc_dec.increment(3), 4) # checks if the results is 4 when x = 3
          def test_decrement(self):
              self.assertEqual(inc_dec.decrement(3), 4)
      if __name__ == '__main__':
    7. Each test framework has its own conventions for naming test files and structuring the tests within, as described in the following sections. Each case includes two test methods, one of which is intentionally set to fail for the purposes of demonstration.
      • each testing framework has own naming conventions
      • each case includes two test methods (one of which fails)
    8. Nose2, the successor to Nose, is just unittest with plugins

      Nose2 testing

    9. Python tests are Python classes that reside in separate files from the code being tested.
    10. general background on unit testing, see Unit Testing on Wikipedia. For a variety of useful unit test examples, see https://github.com/gwtw/py-sorting
    11. Running the unit test early and often means that you quickly catch regressions, which are unexpected changes in the behavior of code that previously passed all its unit tests.


    12. Developers typically run unit tests even before committing code to a repository; gated check-in systems can also run unit tests before merging a commit.

      When to run unit tests:

      • before committing
      • ideally before merging
      • many CI systems run it after every build
    13. in unit testing you avoid external dependencies and use mock data or otherwise simulated inputs

      Unit tests are small, isolated piece of code making them quick and inexpensive to run

    14. The practice of test-driven development is where you actually write the tests first, then write the code to pass more and more tests until all of them pass.

      Essence of TDD

    15. The combined results of all the tests is your test report

      test report

    16. each test is very simple: invoke the function with an argument and assert the expected return value.

      e.g. test of an exact number entry:

          def test_validator_valid_string():
              # The exact assertion call depends on the framework as well
              assert(validate_account_number_format("1234567890"), true)
    17. Unit tests are concerned only with the unit's interface—its arguments and return values—not with its implementation
    18. unit is a specific piece of code to be tested, such as a function or a class. Unit tests are then other pieces of code that specifically exercise the code unit with a full range of different inputs, including boundary and edge cases.

      Essence of unit testing