pytest migration: models: switch to standard assert statements Use unittest2pytest to replace unittest-style assert statements (e.g. assertEqual) with standard Python assert statements to benefit from pytest's improved reporting on assert failures. The conversion by unittest2pytest was correct except for: - 'import pytest' is not automatically added when needed - line wrapping in string formatting caused a syntax error in the transformed code. Reported upstream at https://github.com/pytest-dev/unittest2pytest/issues/3 . - in assertRaises with a lambda, the lambda needs to be removed