Add test guards

Change-Id: I34e48e4ce4fd14e6c92601412f5029aa08efe8fc

tests/python/contrib/test_ethosu/cascader/test_ethosu_conv2d_matcher.py

@@ -14,12 +14,15 @@
 # KIND, either express or implied.  See the License for the
 # specific language governing permissions and limitations
 # under the License.
+import pytest
+
+pytest.importorskip("ethosu.vela")
+
 from tvm import te
 import tvm.contrib.ethosu.cascader as cs
 from tvm.relay.backend.contrib.ethosu.te.convolution import match_ethosu_conv2d, conv2d_compute
 
 import numpy as np
-import pytest
 
 
 def _make_matrices(kernel, stride, dilation, padding, ifm_channels, ifm_layout, ofm_layout):

tests/python/contrib/test_ethosu/cascader/test_ethosu_inline_matcher.py

@@ -14,13 +14,15 @@
 # KIND, either express or implied.  See the License for the
 # specific language governing permissions and limitations
 # under the License.
+import pytest
+
+pytest.importorskip("ethosu.vela")
+
 from tvm import te
 from tvm.topi.transform import reshape
 import tvm.contrib.ethosu.cascader as cs
 from tvm.relay.backend.contrib.ethosu.te.inline import match_ethosu_inline
 
-import pytest
-
 
 def test_ethosu_inline_matcher():
     ifm_shape = (2, 5, 6)

tests/python/contrib/test_ethosu/cascader/test_ethosu_part.py

@@ -14,11 +14,13 @@
 # KIND, either express or implied.  See the License for the
 # specific language governing permissions and limitations
 # under the License.
+import pytest
+
+pytest.importorskip("ethosu.vela")
+
 import tvm.contrib.ethosu.cascader as pl
 from tvm.contrib.ethosu.cascader.parts import EthosuPart
 
-import pytest
-
 
 def test_ethosu_part():
     te_subgraph = pl.TESubgraph([], None)