When we create/add/plug a new device to Mac OS, the newly added device
is possible to be the new default device (depends on system setting?).
In test_unplug_a_device_on_an_active_stream, we didn't check if the
default device is the expected one. The created device in that function
could be the default device in some tests, and it could be non-default
device in some tests. We need to check if the created device is default
or non-default before running the tests. Otherwise we may use the wrong
device to run the tests.
When we create/add/plug a new device to Mac OS, the newly added device is possible to be the new default device (depends on system setting?). In
test_unplug_a_device_on_an_active_stream
, we didn't check if the default device is the expected one. The created device in that function could be the default device in some tests, and it could be non-default device in some tests. We need to check if the created device is default or non-default before running the tests. Otherwise we may use the wrong device to run the tests.