Add unit tests for models

**Feature request**
It would be great to have compression for parsers.

**Use case**
Many users need this functionality for production deployments.

**Implementation idea**
Add a new config option `enable_compression` with default `false`.

No files, tests, or entry points are named. Start by locating the parser, model, and configuration code, then identify the existing unit-test patterns; done means coverage for the new enable_compression option and confirmation that its default is false.

Written by the indexing model from the issue text.