Context

The Goal of this MR is to start the refactoring of the mempool integrations test (#1657).

The MR aims to be a smaller part of !3418 (closed). More (smaller) MR will follow for other tests

Manually testing the MR

This MR does not adds any test. Current tests can be run with the following command :

dune exec tezt/tests/main.exe -- mempool -v

Document the interface of any function added or modified (see the coding guidelines)
n/a Document any change to the user interface, including configuration parameters (see node configuration)
Provide automatic testing (see the testing guide).
n/a For new features and bug fixes, add an item in the appropriate changelog (docs/protocols/alpha.rst for the protocol and the environment, the Development Version section of CHANGES.md for everything else).
Select suitable reviewers using the Reviewers field below.
Select as Assignee the next person who should take action on that MR

Edited Oct 13, 2021 by Albin Coquereau