Also avoid overriding variables, as they are used for assertions.

Make same trade date on accounting path and trade model path.

Store causality on documents.

Also move invoice directly to delivered state.

Avoid rounding, as this solves UI problems which shall be addressed in
different way.

Avoid manual hack, as they can be addressed by builder and rule configuration.

Store dates on delivery and avoid delivery update.

epr5_invoicing is pure base for invoicing, erp5_simplified_invoicing enables
default invoices with Invoice Lines directly in them.

Simplify the logic to find which Hosting Subscription changed.

Test can leave transaction in erroneous state, revert it.