Advanced E: Python Unit Tests

Reference: Odoo’s Test Framework: Learn Best Practices (Odoo 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.

$ odoo-bin -h
Usage: odoo-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/odoo_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
$ odoo-bin -i account --test-enable
$ # run all the tests in this file
$ odoo-bin --test-file=addons/account/tests/test_account_move_entry.py
$ # test tags can help you filter quite easily
$ odoo-bin --test-tags=/account:TestAccountMove.test_custom_currency_on_account_1

Integration Bots

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 Odoo or not, if you are trying to merge something inside odoo/odoo, odoo/enterprise, odoo/upgrade or on odoo.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 enterprise version (only if there is an enterprise 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.

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.

Robodoo

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

Robodoo 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 robodoo 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 enterprise 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 Odoo employee, you can check those here: https://runbot.odoo.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 enterprise 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 Odoo 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 odoo.tests.common import TransactionCase
from odoo.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 Odoo.

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

• The tests should be independent from 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. This is why 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.

The tests should be located in a tests folder in 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 odoo.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 odoo.tests.common import TransactionCase
from odoo.exceptions import UserError
from odoo.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()