CA with IBM has tested the IBM RDz UT.
The IBM RDz UT allows certain vendors to buy and test z/OS as emulation to the mainframe without the full-blown mainframe.
There is not a 'plugin' for CA Easytrieve.
All of the product features are supported and available on IBM's Rational Developer for System z Unit test ("RDz UT").
You will need to Contact your local CA Technologies representative about CA Mainframe Suite for IBM RDz UT.