Enable ngraph tests for a ngraph engine (#14800)

* Enable ngraph tests for a ngraph engine
test=develop

* Move the test structure to other place
test=develop

* Add USE_NGRAPH flag, simple structure
test=develop

python/paddle/fluid/tests/unittests/CMakeLists.txt

@@ -111,3 +111,7 @@ py_test_modules(test_parallel_executor_transformer MODULES test_parallel_executo
 if(NOT APPLE)
     py_test_modules(test_image_classification_resnet MODULES test_image_classification_resnet SERIAL)
 endif()
+
+if (WITH_NGRAPH)
+    add_subdirectory(ngraph)
+endif()

python/paddle/fluid/tests/unittests/ngraph/CMakeLists.txt

@@ -0,0 +1,6 @@
+file(GLOB TEST_OPS RELATIVE "${CMAKE_CURRENT_SOURCE_DIR}" "test_*.py")
+string(REPLACE ".py" "" TEST_OPS "${TEST_OPS}")
+
+foreach(TEST_OP ${TEST_OPS})
+    py_test_modules(${TEST_OP} MODULES ${TEST_OP}  ENVS FLAGS_use_ngraph=true)
+endforeach(TEST_OP)

python/paddle/fluid/tests/unittests/ngraph/__init__.py

@@ -0,0 +1,13 @@
+#   Copyright (c) 2018 PaddlePaddle Authors. All Rights Reserve.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.