fix(schema): Allow for locale: false in schema add tests

[blackboxsw]

Proposed Commit Message

fix(schema): Allow for locale: false in schema add tests


Also refactor and pytestify tests dropping use of
FilesystemMockingTestCase.

Additional Context

Test Steps

Merge type

• Squash merge using "Proposed Commit Message"
• Rebase and merge unique commits. Requires commit messages per-commit each referencing the pull request number (#<PR_NUM>)

[holmanb]

@blackboxsw it looks like this is still failing tests

[holmanb]

LGTM, thanks for the test cleanups!