PTF Peoplesoft Test Framework. How to identify if a Message Box was displayed or not

Poeplesoft Test Framework Tools 8.59.01

I want to write a test case to validate a Peoplecode I wrote (End Date cannot be less than Start Date). I have a SaveEdit peoplecode that displays a ERROR message when End Date is less than Start Date. 

I am trying to write a Test Case to capture a situation where the validation peoplecode that I wrote does not fire (for whatever the reason may be) and as a result invalid data gets stored in database. One scenario this could happen is if the validation peoplecode does not make it to test environment during migration.