Better success_result_of() implementation.
Docs for PersistenceHelper.
Merge branch 'develop' into feature/issue-707-test-helper-tests-and-docs-2
Better patching mechanism for PersistenceHelper and a bunch of tests.
Tests for import_skip().
More PersistenceHelper tests.
Tests for PersistenceHelper cleanup.
Minor fixes to test helper docs and tests.
Test patched manager constructors.
Merge branch 'feature/issue-707-test-helper-tests-and-docs-2' into develop