Fix/batching and skip index tests

[mdbenito]

Description

This PR fixes recurrent issues with a test for sampled batches.

Changes

• Instead of using a valuation, reduce the scope of the test to the actual batching
• Also test skip_indices with batches (and add support for a couple of methods which was already there)

Checklist

• Wrote Unit tests (if necessary)
• Updated Documentation (if necessary)
• Updated Changelog
• If notebooks were added/changed, added boilerplate cells are tagged with "tags": ["hide"] or "tags": ["hide-input"]