19.26Then write scenarios

I prefer Given / When / Then because business people can review them.

Example:

Given customer C001 already exists in Salesforce
with Phone = 111

When source sends C001 with Phone = 222

Then the existing Account is updated
and no new Account is created

Another:

Given customer C001 already exists
with Phone = 111

When source sends C001 without a Phone field

Then Salesforce Phone remains 111

These are much easier for Product to approve than Mule XML.