tests: pytest xfail is used instead of skipping

trezorlib/tests/device_tests/test_msg_nem_getaddress.py

@@ -18,7 +18,7 @@
 from .common import *
 
 
-@pytest.mark.skip_t2
+@pytest.mark.xfail  # to be removed when nem is merged
 class TestMsgNEMGetaddress(TrezorTest):
 
     def test_nem_getaddress(self):

trezorlib/tests/device_tests/test_msg_nem_signtx.py

@@ -22,7 +22,7 @@ from trezorlib import nem
 
 
 # assertion data from T1
-@pytest.mark.skip_t2
+@pytest.mark.xfail  # to be removed when nem is merged
 class TestMsgNEMSignTx(TrezorTest):
 
     def test_nem_signtx_simple(self):

trezorlib/tests/device_tests/test_msg_nem_signtx_mosaics_t2.py

@@ -24,7 +24,7 @@ import time
 
 # assertion data from T1
 @pytest.mark.skip_t1
-@pytest.mark.skip_t2
+@pytest.mark.xfail  # to be removed when nem is merged
 class TestMsgNEMSignTxMosaics(TrezorTest):
 
     def test_nem_signtx_mosaic_supply_change(self):

trezorlib/tests/device_tests/test_msg_nem_signtx_other.py

@@ -23,7 +23,7 @@ import time
 
 
 # assertion data from T1
-@pytest.mark.skip_t2
+@pytest.mark.xfail  # to be removed when nem is merged
 class TestMsgNEMSignTxOther(TrezorTest):
 
     def test_nem_signtx_aggregate_modification(self):