switch pytest to use INTERPRETER backend for testing (#1383)

python/test/conftest.py

@@ -17,7 +17,7 @@ import pytest
 
 
 def pytest_addoption(parser):
-    parser.addoption('--backend', default='CPU',
+    parser.addoption('--backend', default='INTERPRETER',
                      choices=['INTERPRETER', 'CPU', 'GPU', 'NNP'],
                      help='Select from available backends')
 

python/test/ngraph/test_basic.py

@@ -164,7 +164,7 @@ def test_bad_data_shape():
     A = ng.parameter(shape=[2, 2], name='A', dtype=np.float32)
     B = ng.parameter(shape=[2, 2], name='B')
     model = (A + B)
-    runtime = ng.runtime(backend_name='CPU')
+    runtime = ng.runtime(backend_name='INTERPRETER')
     computation = runtime.computation(model, A, B)
 
     value_a = np.array([[1, 2]], dtype=np.float32)