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Pack Testing

This section includes information on pack testing - where to put the tests, how to write the tests, mock classes which can be used to make testing easier, etc.

Test File Locations and Names

All the test files should go into <pack name>/tests/ directory. If tests include any fixtures, they should be put in the <pack name>/tests/fixtures/ directory.

Test files should follow the following naming conventions:

  • test_action_<action name>.py for action tests. For example, if the action is named parse_xml, the file should be named
  • test_sensor_<sensor name>.py for sensor tests. For example, if the sensor is named GithubEvents, the file should be named
  • for all the action aliases tests.

General Testing Conventions

Most of the EWC packs interact with a third party API or tool. Writing full-blown integration and end-to-end tests would be very time consuming and hard, so the convention is to write unit tests and mock the responses and method calls where necessary.

Base Test Classes and Mock Classes

To make testing easier, EWC provides some base test and mock classes you can use in the tests.

Base Test Classes

  • st2tests.base.BaseSensorTestCase - Base class for all the sensor test cases. This class provides utility methods for making sensor testing easier, such as returning a sensor class instance with sensor_service correctly populated, a method for asserting that trigger has been dispatched (assertTriggerDispatched) and more.
  • st2tests.base.BaseActionTestCase - Base class for all the action test cases. This class provides utility methods for making action testing easier such as returning an action class with action_service correctly populated, etc.
  • st2tests.BaseActionAliasTestCase - Base class for all the action aliases test cases. This class provides utility functions for testing the action alias.

Mock Classes

  • st2tests.mocks.runner.MockActionRunner - Mock action runner class which allows you to specify a mock status, result and context which is returned from the run method.
  • st2tests.mocks.sensor.MockSensorWrapper - Mock SensorWrapper class.
  • st2tests.mocks.sensor.MockSensorService - Mock SensorService class. This class mocks methods which operate on the datastore items (get_logger, list_values, get_value, set_value, delete_value).
  • st2tests.mocks.action.MockActionWrapper - Mock PythonActionWrapper class.
  • st2tests.mocks.action.MockActionService - Mock ActionService class. This class mocks methods which operate on the datastore items (list_values, get_value, set_value, delete_value).


In addition to the EWC and pack dependencies listed in requirements.txt and requirements-tests.txt, the following libraries are also available by default inside the tests:

  • unittest2
  • mock

The sensors (<pack name>/sensors/) and actions (<pack name>/actions/) directory is added to PYTHONPATH meaning you can import sensor and action modules directly in your code.

For example, if you have an action file named actions/ you can do the following inside your test module:

import parse_xml

Keep in mind that both sensor and action modules are not namespaced which means sensor and action module names need to be unique to avoid conflicts.


All the fixture data such as raw HTTP responses and similar, should be stored in files in the <pack path>/tests/fixtures directory (e.g. libcloud/tests/fixtures/list_zones.json).

To retrieve raw content of the fixture file you can use the get_fixture_content method available on the test class.

Instantiating and obtaining class instances

When obtaining a sensor or an action class instance you should use get_sensor_instance and get_action_instance methods provided on the base test class instead of directly instantiating the sensor/action class yourself.

This is important because those two methods mimic the class initialization process which is otherwise performed inside the action/sensor wrapper.

Sensor tests:

class MySensorSensorTestCase(BaseSensorTestCase):
    sensor_cls = MySensor

    def test_method(self):
        sensor = self.get_sensor_instance(config={'foo': 'bar'})
        # ...

Action tests:

class MyActionActionTestCase(BaseActionTestCase):
    action_cls = MyAction

    def test_method(self):
        action = self.get_action_instance(config={'foo': 'bar'})
        result =
        # ...

Action alias tests:

class MyActionAliasTestCase(BaseActionTestCase):
    action_alias_name = 'my_alias'

    def test_method(self):
        action_alias_db = self.action_alias_db

As you can see, when testing aliases you need to specify the name of the alias which is to be tested. This alias is automatically retrieved from disk and available via self.action_alias_db instance variable.

Sample Tests

Here’s some example tests:

Running Tests


For this script to work correctly, all the StackStorm components need to be in PYTHONPATH. This is already the case when using st2vagrant Vagrant image or when StackStorm is installed on a system using deb/rpm packages.

If that is not the case, you need to set ST2_REPO_PATH environment variable to point to the git checkout of the StackStorm st2 repository as shown below:

git clone /tmp/st2
ST2_REPO_PATH=/tmp/st2 st2-run-pack-tests -p <pack path>

To run all the tests in a particular pack you can use the st2-run-pack-tests script (st2common/bin/st2-run-pack-tests) from the st2 repository:

st2-run-pack-tests -p <pack path>

For example:

st2-run-pack-tests -p /data/packs/docker/

By default, this script will create and use a new temporary virtual environment for each pack test run and install all the dependencies which are required to run the tests inside this virtual environment.

If you want to avoid virtual environment creation (e.g. the virtual environment already exists or you have created one manually), you can pass the -x flag to the script. This flag will tell it to skip virtual environment creation, but all the necessary dependencies will still be installed.

If you are running this script inside a development VM (st2vagrant), you can safely pass the -x flag to the script since a virtual environment should already be created and all the necessary EWC dependencies should be available in PYTHONPATH.

In addition to that, if all the pack dependencies are already installed and you want to skip installing and updating the dependencies, you can pass the -j flag to the script (this will cause the script to just run the pack tests directly):

For example:

st2-run-pack-tests -p /data/packs/docker/ -x -j

Alternatively, if a virtual environment for tests has already been created during previous tool invocation, you can skip updating of the virtual environment and just run the tests by using the -j flag (this will speed things up because the virtual environment will be used as-is and only tests will run):

# First run - create tests virtual environment and run the tests
st2-run-pack-tests -p /data/packs/docker/

# Second (and subsequent) runs - just run the tests and re-use the existing
# virtual environment which has been created during the previous script
# invocation.
st2-run-pack-tests -p /data/packs/docker/ -j

As more tests are developed it is always a good idea to determine how much code has been covered by the tests and how much remains un-tested. Calculated test coverage can be printed out using the -c option.

st2-run-pack-tests -c -p /data/packs/docker/

The command will print out test coverage to stdout along with generating a coverage report in cover/index.html. This can be opened with any modern browser. The directory cover will be created in the current working directory when the command st2-run-pack-tests is invoked.

Understanding how long a test takes to run is sometimes important. Timing metrics can be enabled via the -t option.

st2-run-pack-tests -t -p /data/packs/docker/

Lint Tools and Scripts

In addition to tests, the st2sdk repository and package also ships with various other tools and lint scripts which allow you to catch common errors and typos automatically and early.

For more information on those scripts and how to use them, please refer to the README in the st2sdk repository.

Continuous Integration

By default, the lint scripts mentioned above and tests for all the packs run on every commit to st2 and StackStorm-Exchange.