Safeguard your code with unit tests¶

Important

This tutorial is an extension of the Getting started tutorial. Make sure you have completed it and use the estate module you have built as a base for the exercises in this tutorial. Fetch the branch 3.0-core from the technical-training-solutions repository if you want to start from a clean base.

Reference: Flectra’s Test Framework: Learn Best Practices (Flectra Experience 2020) on YouTube.

Writing tests is a necessity for multiple reasons. Here is a non-exhaustive list:

Ensure code will not be broken in the future
Define the scope of your code
Give examples of use cases
It is one way to technically document the code
Help your coding by defining your goal before working towards it

Running Tests¶

Before knowing how to write tests, we need to know how to run them.

$ flectra-bin -h
Usage: flectra-bin [options]

Options:
--version             show program's version number and exit
-h, --help            show this help message and exit

[...]

Testing Configuration:
  --test-file=TEST_FILE
                      Launch a python test file.
  --test-enable       Enable unit tests.
  --test-tags=TEST_TAGS
                      Comma-separated list of specs to filter which tests to
                      execute. Enable unit tests if set. A filter spec has
                      the format: [-][tag][/module][:class][.method] The '-'
                      specifies if we want to include or exclude tests
                      matching this spec. The tag will match tags added on a
                      class with a @tagged decorator (all Test classes have
                      'standard' and 'at_install' tags until explicitly
                      removed, see the decorator documentation). '*' will
                      match all tags. If tag is omitted on include mode, its
                      value is 'standard'. If tag is omitted on exclude
                      mode, its value is '*'. The module, class, and method
                      will respectively match the module name, test class
                      name and test method name. Example: --test-tags
                      :TestClass.test_func,/test_module,external  Filtering
                      and executing the tests happens twice: right after
                      each module installation/update and at the end of the
                      modules loading. At each stage tests are filtered by
                      --test-tags specs and additionally by dynamic specs
                      'at_install' and 'post_install' correspondingly.
  --screencasts=DIR   Screencasts will go in DIR/{db_name}/screencasts.
  --screenshots=DIR   Screenshots will go in DIR/{db_name}/screenshots.
                      Defaults to /tmp/flectra_tests.

$ # run all the tests of account, and modules installed by account
$ # the dependencies already installed are not tested
$ # this takes some time because you need to install the modules, but at_install
$ # and post_install are respected
$ flectra-bin -i account --test-enable
$ # run all the tests in this file
$ flectra-bin --test-file=addons/account/tests/test_account_move_entry.py
$ # test tags can help you filter quite easily
$ flectra-bin --test-tags=/account:TestAccountMove.test_custom_currency_on_account_1

Integration Bots¶

Note

This section is only for Flectra employees and people that are contributing to github.com/flectra. We highly recommend having your own CI otherwise.

When a test is written, it is important to make sure it always passes when modifications are applied to the source code. To automate this task, we use a development practice called Continuous Integration (CI). This is why we have some bots running all the tests at different moments. Whether you are working at Flectra or not, if you are trying to merge something inside flectra/flectra, flectra/professional, flectra/upgrade or on flectra.sh, you will have to go through the CI. If you are working on another project, you should think of adding your own CI.

Runbot¶

Reference: the documentation related to this topic can be found in Runbot FAQ.

Most of the tests are run on Runbot every time a commit is pushed on GitHub.

You can see the state of a commit/branch by filtering on the runbot dashboard.

A bundle is created for each branch. A bundle consists of a configuration and batches.

A batch is a set of builds, depending on the parameters of the bundle. A batch is green (i.e. passes the tests) if all the builds are green.

A build is when we launch a server. It can be divided in sub-builds. Usually there are builds for the community version, the professional version (only if there is an professional branch but you can force the build), and the migration of the branch. A build is green if every sub-build is green.

A sub-build only does some parts of what a full build does. It is used to speed up the CI process. Generally it is used to split the post install tests in 4 parallel instances. A sub-build is green if all the tests are passing and there are no errors/warnings logged.

Note

All tests are run regardless of the modifications done. Correcting a typo in an error message or refactoring a whole module triggers the same tests. All modules will be installed as well. This means something might not work even if the Runbot is green, i.e. your changes depend on a module that the module the changes are in doesn’t depend on.
The localization modules (i.e. country-specific modules) are not installed on Runbot (except the generic one). Some modules with external dependencies can also be excluded.
There is a nightly build running additional tests: module operations, localization, single module installs, multi-builds for nondeterministic bugs, etc. These are not kept in the standard CI to shorten the time of execution.

You can also login to a build built by Runbot. There are 3 users usable: admin, demo and portal. The password is the same as the login. This is useful to quickly test things on different versions without having to build it locally. The full logs are also available; these are used for monitoring.

Robflectra¶

You will most likely have to gain a little bit more experience before having the rights to summon robflectra, but here are a few remarks anyways.

Robflectra is the guy spamming the CI status as tags on your PRs, but he is also the guy that kindly integrates your commits into the main repositories.

When the last batch is green, the reviewer can ask robflectra to merge your PR (it is more a rebase than a merge). It will then go to the mergebot.

Mergebot¶

Mergebot is the last testing phase before merging a PR.

It will take the commits in your branch not yet present on the target, stage it and rerun the tests one more time, including the professional version even if you are only changing something in community.

This step can fail with a Staging failed error message. This could be due to

a nondeterministic bug that is already on the target. If you are an Flectra employee, you can check those here: https://runbot.flectra.com/runbot/errors
a nondeterministic bug that you introduced but wasn’t detected in the CI before
an incompatibility with another commit merged right before and what you are trying to merge
an incompatibility with the professional repository if you only did changes in the community repo

Always check that the issue does not come from you before asking the merge bot to retry: rebase your branch on the target and rerun the tests locally.

Modules¶

Because Flectra is modular, the tests need to be also modular. This means tests are defined in the module that adds the functionality you are adding in, and tests cannot depend on functionality coming from modules your module doesn’t depend on.

Reference: the documentation related to this topic can be found in Special Tags.

from flectra.tests.common import TransactionCase
from flectra.tests import tagged

# The CI will run these tests after all the modules are installed,
# not right after installing the one defining it.
@tagged('post_install', '-at_install')  # add `post_install` and remove `at_install`
class PostInstallTestCase(TransactionCase):
    def test_01(self):
        ...

@tagged('at_install')  # this is the default
class AtInstallTestCase(TransactionCase):
    def test_01(self):
        ...

If the behavior you want to test can be changed by the installation of another module, you need to ensure that the tag at_install is set; otherwise, you can use the tag post_install to speed up the CI and ensure it is not changed if it shouldn’t.

Writing a test¶

Reference: the documentation related to this topic can be found in Python unittest and Testing Flectra.

Here are a few things to take into consideration before writing a test

The tests should be independent of the data currently in the database (including demo data)
Tests should not impact the database by leaving/changing residual data. This is usually done by the test framework by doing a rollback. Therefore, you must never call cr.commit in a test (nor anywhere else in the business code).
For a bug fix, the test should fail before applying the fix and pass after.
Don’t test something that is already tested elsewhere; you can trust the ORM. Most of the tests in business modules should only test the business flows.
You shouldn’t need to flush data into the database.

Note

Remember that onchange only applies in the Form views, not by changing the attributes in python. This also applies in the tests. If you want to emulate a Form view, you can use flectra.tests.common.Form.

The tests should be in a tests folder at the root of your module. Each test file name should start with test_ and be imported in the __init__.py of the test folder. You shouldn’t import the test folder/module in the __init__.py of the module.

estate
├── models
│   ├── *.py
│   └── __init__.py
├── tests
│   ├── test_*.py
│   └── __init__.py
├── __init__.py
└── __manifest__.py

All the tests should extend flectra.tests.common.TransactionCase. You usually define a setUpClass and the tests. After writing the setUpClass, you have an env available in the class and can start interacting with the ORM.

These test classes are built on top of the unittest python module.

from flectra.tests.common import TransactionCase
from flectra.exceptions import UserError
from flectra.tests import tagged

# The CI will run these tests after all the modules are installed,
# not right after installing the one defining it.
@tagged('post_install', '-at_install')
class EstateTestCase(TransactionCase):

    @classmethod
    def setUpClass(cls):
        # add env on cls and many other things
        super(EstateTestCase, cls).setUpClass()

        # create the data for each tests. By doing it in the setUpClass instead
        # of in a setUp or in each test case, we reduce the testing time and
        # the duplication of code.
        cls.properties = cls.env['estate.property'].create([...])

    def test_creation_area(self):
        """Test that the total_area is computed like it should."""
        self.properties.living_area = 20
        self.assertRecordValues(self.properties, [
           {'name': ..., 'total_area': ...},
           {'name': ..., 'total_area': ...},
        ])


    def test_action_sell(self):
        """Test that everything behaves like it should when selling a property."""
        self.properties.action_sold()
        self.assertRecordValues(self.properties, [
           {'name': ..., 'state': ...},
           {'name': ..., 'state': ...},
        ])

        with self.assertRaises(UserError):
            self.properties.forbidden_action_on_sold_property()

Note

For better readability, split your tests into multiple files depending on the scope of the tests. You can also have a Common class that most of the tests should inherit from; this common class can define the whole setup for the module. For instance, in account.

Exercise

Update the code so no one can:

Create an offer for a sold property
Sell a property with no accepted offers on it

and create tests for both of these cases. Additionally check that selling a property that can be sold is correctly marked as sold after selling it.

Exercise

Someone keeps breaking the reset of Garden Area and Orientation when you uncheck the Garden checkbox. Make sure it doesn’t happen again.

Tip

Tip: remember the note about Form a little bit above.

Edit on GitHub