How to Contribute


This section will provide details on how to contribute changes to the project covering both the mechanics of how to contribute new code as well as how to adhere to the code quality and coding practices of the project.


As this project is part of the overall ONAP project, there are some common guidelines and activities you will need to adhere to:

Other useful links:

  • All work is documented and tracked via the VVP Project in the ONAP JIRA instance. Login is via your Linux Foundation ID
  • Proposals for new features, general information about the projects, meeting minutes, and ONAP process information is located on the ONAP Wiki
  • The VVP project hosts a weekly meeting to plan upcoming work, discuss open issues, and align on priorities. Please consider attending if possible if you intend to contribute to the project. Refer to the ONAP Calendar for scheduling details


The primary focus of VVP is ensuring that a VNF that is described using Openstack Heat complies with the ONAP Heat requirements specified in the VNF Requirements (VNFRQTS) project. If a VNF does not comply with these rules, then it may not successfully be modeled in SDC, fail to instantiate, be improperly inventoried in A&AI, or fail orchestration.

The project aims to validate every mandatory requirement in the VNF Requirements related to Heat (i.e. all requirements with a MUST or MUST NOT keyword)

Heat templates are validated using tests written in pytest. Each test will validate one or more requirements. Typically we strive to have 1 test per requirement, but there are situations where it is easiest and clearest to validate multiple, tightly related requirements with a single test.

Every test MUST have a corresponding requirement in the ONAP VNF Requirements project. If your contribution is a test and there is not an appropriate requirement, then please consider making a contribution to that project first.

Writing Tests

Coding Conventions

  • Follow PEP-8 conventions
    • NOTE: The only variation is that the line-length can be 88 characters vs. 80
  • All code must be formatted using the Black code formatter. VVP uses the pre-commit library to automatically format code at check-in. After running pip install, run pre-commit install to initialize the git hook.

  • Familiarize yourself with the utilities that exist in the following utility modules and leverage them to avoid duplication.

    • ice_validator/tests/
    • ice_validator/tests/
    • ice_validator/tests/utils/**
  • Ensure all source files include the standard Apache License 2.0 text and appropriate copyright statement (see other source files for example)

  • All code must pass standard quality checks prior to submission which can be executed via tox or by running

  • When parsing YAML, always use the tests/cached_yaml module versus the default yaml module. This will greatly improve performance due to the large number of yaml files that must be parsed.

  • In an effort to keep the number of dependencies down, please favor using the Python standard library unless using an external library significantly improves or reduces the needed code to implement the functionality.

  • For security purposes the following hardening activities are used:

    • Avoid usage of yaml.load and always use yaml.safe_load (Note: if you use cached_yaml as instructed above, then this is covered automatically)
    • Docker containers must not be run as root (see current Dockerfile for an example)
    • Inspect and resolve all findings by the bandit scans

File Name

Test files are written in Python, and should go into the /validation-scripts/ice_validator/tests/ directory. They should be prefixed with test_. If not, pytest will not discover your test. The file name should reflect what is being tested.

Test Name

Tests are functions defined in the test file, and also must be prefixed with test_. If not, pytest will not collect them during execution. For example:

def test_my_new_requirement():

Requirement Decorator

Each test function must be decorated with a requirement ID from the VNF Requirements project. The following is required to be imported at the top of the test file:

from tests.helpers import validates

Then, your test function should be decorated like this:

           "R-123457") # these requirement IDs should come from the VNFRQTS project
def test_my_new_requirement():

This decorator is used at the end of the test suite execution to generate a report that includes the requirements that were violated. If a test is not decorated it is unclear what the reason for a failure is, and the implication is that the test is not needed.

The validation reports will show the requirement text that was violated and it will be pulled from the heat_requirements.json file. This file is published by the VNFRQTS project, and VVP maintains a copy of the file. Your requirement should be present in this file. The command can be used to re-synchronize the VVP copy with VNFRQTS master.

Test Parameters

There are several dynamic fixtures that can be injected into a test based on what the test is attempting to validate. Each test should be parameterized based on what artifact is being validated.

Available parameters are enumerated in /validation-scripts/ice_validator/tests/ Below is a description of the most commonly used:

  • heat_template: parameter is the full path name for a file with the extenstion .yaml or .yml, if the file also has a corresponding file with the same name but extension .env.
  • yaml_file: parameter is the full path name for a file with the extenstion .yaml or .yml
  • yaml_files: parameter is a list of all files with the extenstion .yaml or .yml.
  • volume_template: parameter is the full path name for a file name that ends with _volume and the extension .yaml or .yml.

There are many others that can also be used, check for the full list.

The parameter that you decide to use determines how many times a test is executed, and what data is available to validate. For example, if the test suite is executed against a directory with 10 .yaml files, and a test is using the parameter yaml_file, the test will be executed once for each file, for a total of 10 executions. If the parameter yaml_files (note the plural) is used instead, the test will only execute once.

Here’s an example for how to parameterize a test:

def test_my_new_requirement(yaml_file): # this test will execute for each .yaml or .yml

Collecting Failures

To raise a violation to pytest to be collected and included on the final violation report, use the assert statement. Example:

def test_my_new_requirement(yaml_file):
  my test logic

  assert not failure_condition, error_message

As one of the VVP priorities is User Comprehension, the error_message should be readable and include helpful information for triaging the failure, such as the yaml_file, the parameter the test was checking, etc…

If the assert statement fails, the failure is collected by pytest, and the decorated requirements and error_message are included in the final report.

Optional: Pytest Markers and Validation Categories

The VVP test suite has the concept of a base test. These are used as sanity tests and are executed before the other tests, and if they fail the test suite execution is halted. A test should be annotated with base if the failure is likely to generate many subsequent failures (ex: improperly formatted YAML). If you are writing a base test, mark your test like this:

import pytest

@pytest.mark.base # this is the base test marker
def test_my_new_requirement():

The VVP test suite also has the concept of a category to define what additional set of optional tests to execute when requested by the end user. The way it works is by applying the categories decorator to the test.

By default, all base tests and tests with no category are executed. If you want an additional category to run, pass the command line argument:


This will extend the default set of tests to also include tests marked with the requested category like the following:

import pytest

@categories("<category>") # substitue <category> with the category name
def test_my_new_requirement():

This should be used sparingly, and in practice consider reviewing a requirement with the VNF Requirements team before adding a test to a category.

Testing your Test

Every Heat validation test must have a unit test that validates the test is working as expected. This is handled by creating a one or more “fixtures” that will exercise the test and validate the expected result.

The fixtures are stored in the ice_validator/tests/fixtures directory under a directory that matches the test file name exactly.

For example, if your test is named, then the test fixtures must be in the ice_validator/tests/fixtures/test_neutron_ports/ directory.

At minimum, each test must have one example of heat templates/files that pass (stored in the pass subdirectory), and one example that fails ( stored in the fail subdirectory). These templates do not need to be complete, valid Heat template - they only need to include the minimum content to validate the test.

If you need to test multiple conditions or branches of your test, then you can nest other directories under your test’s fixture directory. Each nested directory, must in turn have a pass and fail subdirectory.

To execute all tests for the entire suite, issue the following commmand from the ice_validator directory:

pytest --self-test

If you wish to selectively execute your test against one of the fixtures, then issue the following command from the ice_validator directory:

pytest tests/<test_file>.py --template-directory=tests/fixtures/<test_file>/<scenario>

If you have contributed code outside of a tests_*.py file, then you should create suitable tests for that functionality in the app_tests directory. The tests should be compatible with pytest, but these tests do not use the fixtures mechanism.

Submitting Your Changes For Review

Once you have completed your changes and tested they work as expected, then the next step is to validate they are ready for submission. The module in the root directory contains are variety of code quality checks that the build server will execute. These can be executed locally using tox or simply running

At the time of this writing, the following checks will be performed:

  • Executing the full test suite (app_tests and --self-test)
  • flake8 code style validation
  • Ensuring the heat_requirements.json file is up-to-date with VNFRQTS (run if this check fails)
  • Ensures all mandatory tests from VNFRQTS have tests in VVP
  • Security checks via bandit

Once all tests are passed, then refer to Pushing Changes Using Git for details on how to submit your change.

Once your change has been submitted, please add the following individuals as reviewers at minimum:

  • Steven Stark
  • Trevor Lovett
  • Steven Wright