Add unit tests for parsers

**Feature request**
It would be great to have retry for handlers.

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

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

First reconcile the title, which asks for parser unit tests, with the body, which requests retry support for handlers. Locate the parser, handler, and configuration entry points, then check how existing tests are organized. Done should include an `enable_retry` option defaulting to `false` and tests covering the requested retry behavior.

Written by the indexing model from the issue text.