Change assertCalledWith to assert_called_with

In test_ptime() 2 uses of the former failed to assert with bogus
values used in the assert.  Using assert_called_with() instead
correctly performs the assertion.

Change-Id: Idbd918f8e8d3ec5a4110725b949710fb54b4ba9a
Merge "Change assertCalledWith to assert_called_with"