tempest/doc/source/microversion_testing.rst

How To Implement Microversion Tests

Tempest provides stable interfaces to test API Microversion. For Details, see: API Microversion testing Framework This document explains how to implement Microversion tests using those interfaces.

Configuration options for Microversion

• Add configuration options for specifying test target Microversions. We need to specify test target Microversions because the supported Microversions may be different between OpenStack clouds. For operating multiple Microversion tests in a single Tempest operation, configuration options should represent the range of test target Microversions. New configuration options are:

  • min_microversion
  • max_microversion

  Those should be defined under respective section of each service. For example:

  [compute]
  min_microversion = None
  max_microversion = latest

How To Implement Microversion Tests

Step1: Add skip logic based on configured Microversion range

Add logic to skip the tests based on Tests class and configured Microversion range. api_version_utils.check_skip_with_microversion function can be used to automatically skip the tests which do not fall under configured Microversion range. For example:

class BaseTestCase1(api_version_utils.BaseMicroversionTest):

    [..]
@classmethod
def skip_checks(cls):
    super(BaseTestCase1, cls).skip_checks()
    api_version_utils.check_skip_with_microversion(cls.min_microversion,
                                                   cls.max_microversion,
                                                   CONF.compute.min_microversion,
                                                   CONF.compute.max_microversion)

Skip logic can be added in tests base class or any specific test class depends on tests class structure.

Step2: Selected API request microversion

Select appropriate Microversion which needs to be used to send with API request. api_version_utils.select_request_microversion function can be used to select the appropriate Microversion which will be used for API request. For example:

@classmethod
def resource_setup(cls):
    super(BaseTestCase1, cls).resource_setup()
    cls.request_microversion = (
        api_version_utils.select_request_microversion(
            cls.min_microversion,
            CONF.compute.min_microversion))

Step3: Set Microversion on Service Clients

Microversion selected by Test Class in previous step needs to be set on service clients so that APIs can be requested with selected Microversion.

Microversion can be defined as global variable on service clients which can be set using fixture. Also Microversion header name needs to be defined on service clients which should be constant because it is not supposed to be changed by project as per API contract. For example:

COMPUTE_MICROVERSION = None

class BaseClient1(rest_client.RestClient):
    api_microversion_header_name = 'X-OpenStack-Nova-API-Version'

Now test class can set the selected Microversion on required service clients using fixture which can take care of resetting the same once tests is completed. For example:

def setUp(self):
    super(BaseTestCase1, self).setUp()
    self.useFixture(api_microversion_fixture.APIMicroversionFixture(
        self.request_microversion))

Service clients needs to add set Microversion in API request header which can be done by overriding the get_headers() method of rest_client. For example:

COMPUTE_MICROVERSION = None

class BaseClient1(rest_client.RestClient):
    api_microversion_header_name = 'X-OpenStack-Nova-API-Version'

    def get_headers(self):
        headers = super(BaseClient1, self).get_headers()
        if COMPUTE_MICROVERSION:
            headers[self.api_microversion_header_name] = COMPUTE_MICROVERSION
        return headers

Step4: Separate Test classes for each Microversion

This is last step to implement Microversion test class.

For any Microversion tests, basically we need to implement a separate test class. In addition, each test class defines its Microversion range with class variable like min_microversion and max_microversion. Tests will be valid for that defined range. If that range is out of configured Microversion range then, test will be skipped.

NOTE: Microversion testing is supported at test class level not at individual test case level. For example:

Below test is applicable for Microversion from 2.2 till 2.9:

class BaseTestCase1(api_version_utils.BaseMicroversionTest,
                    tempest.test.BaseTestCase):

    [..]


class Test1(BaseTestCase1):
    min_microversion = '2.2'
    max_microversion = '2.9'

    [..]

Below test is applicable for Microversion from 2.10 till latest:

class Test2(BaseTestCase1):
    min_microversion = '2.10'
    max_microversion = 'latest'

    [..]

Notes about Compute Microversion Tests

Some of the compute Microversion tests have been already implemented with the Microversion testing framework. So for further tests only step 4 is needed.

Along with that JSON response schema might need versioning if needed.

Compute service clients strictly validate the response against defined JSON schema and does not allow additional elements in response. So if that Microversion changed the API response then schema needs to be versioned. New JSON schema file needs to be defined with new response attributes and service client methods will select the schema based on requested microversion.

If Microversion tests are implemented randomly meaning not in sequence order(v2.20 tests added and previous Microversion tests are not yet added) then, still schema might need to be version for older Microversion if they changed the response. This is because Nova Microversion includes all the previous Microversions behavior.

For Example:

Implementing the v2.20 Microversion tests before v2.9 and 2.19-v2.20 API request will respond as latest behavior of Nova till v2.20, and in v2.9 and 2.19, server response has been changed so response schema needs to be versioned accordingly.

That can be done by using the get_schema method in below module:

The base_compute_client module

tempest.lib.services.compute.base_compute_client

Microversion tests implemented in Tempest

• Compute

• 2.1

• 2.2

• 2.10