Fix Integration test with mock service

[amelendres]

If you are testing a mock service you should have the GIVEN and the VERIFY.

To fix the code I would ask to add one test case addAnExistingBeneficiary

Given an account with "A" Beneficiary
When add and existing "A" Beneficiary
Then the service response status 409 - CONFLICT

spring-pro-code/lab/40-boot-test-solution/src/test/java/accounts/web/AccountControllerBootTests.java

Line 127 in 494bce4

public void addBeneficiary() throws Exception {