unit test with custom EP defaults to CPU EP

[yraparti]

Hi,

I am developing an EP to offload Matmul operator to a custom backend device. As a part of the development I have created a dummy Matmul operator and registered it using KernelRegistry. When I try to test this Matmul operator with op_tester in the unit test suite, it defaults to CPU EP. Am I missing something w.r.to attaching the EP to the session?

-Y