test_serializers: Refactor using pytest
Kept the data as is. Change from unittest form to pytest one.
Related to !149 (closed)
Test Plan
tox
Migrated from D3461 (view on Phabricator)
Kept the data as is. Change from unittest form to pytest one.
Related to !149 (closed)
tox
Migrated from D3461 (view on Phabricator)