For getFullComputerInformation extend test with Slave Instance, and modify
original. Those test shall check complex computer, and having Slave Instance
follows the idea of computer complexity.

In case of other methods add _withSlave variants. Those tests are checking
specific access, and shall be separated from its non-Slave variants.

After requesting destruction and running simulateSlapgridUR the partitions are
free.

The user which request instance on public computer was able to read its
connection parameters and they were correctly set during simulateSlapgridCP run.

Interaction workflow are required to automate recalculation.

In case of non live test rely on ERP5TypeTestCase to play with MailHost.

In case of live test do not use _setUpDummyMailHost and _restoreMailHost,
which are class based changes, but directly add and remove the object.

Permissions are not checked as it is part of erp5 bt5.

reference of Software Instance does not impact its role's calculation.

Such assertion is already provided by
slapos_assert_hosting_subscription_predecessor alarm.

The category table does not index any non strict link to the computer. It is
not possible in such case to directly use the uid value.