The objective for the VVP test suite is for each test to directly correlate with at least one requirement in the VNF Requirements project in ONAP. If the test you intend to write doesn’t have a corresponding requirement in the VNF Requirements project, consider making a contribution to that project first.

Convenience vs Convention

There are a lot of ways to write tests. Priorities for the VVP test suite are

  • Accuracy
  • User Comprehension

The test suite is often used by people who don’t write code, or people who aren’t devoted to writing python validation tests.

The output of failed validation tests can be difficult to read, so keep that in mind when you are deciding whether to create another level of abstraction vs having some code duplication or verbose tests.

Writing Tests

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.

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 should 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 .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.

Test Parameters

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. 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. The way it works is by using categories decorator.

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 execute all base tests, non-marked tests, and tests marked 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.