add test skeleton

Author: Yang Yang

src/backward.cc

@@ -0,0 +1,19 @@
+// Copyright (c) 2018 PaddlePaddle Authors. All Rights Reserved.
+//
+// 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.
+
+#include "src/tape.h"
+
+namespace paddle {
+namespace tape {}  // namespace tape
+}  // namespace paddle

src/test_backward.cc

@@ -0,0 +1,53 @@
+// Copyright (c) 2018 PaddlePaddle Authors. All Rights Reserved.
+//
+// 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.
+
+#include "gtest/gtest.h"
+#include "src/function.h"
+
+/*
+ * y = op(x)
+ * z = op(x)
+ * loss = y + z
+ */
+TEST(Backward, TestMultipleAssignment) {}
+
+/*
+ * loss = x + x
+ */
+TEST(Backward, TestInplaceSum) {}
+
+/*
+ * y = op(x)  // y@grad is not initialized
+ * loss = op(z)
+ */
+TEST(Backward, TestEmptyGrad) {}
+
+/*
+ * vector<> v
+ * for i in dim(x, 0):
+ *   y = x.Slice(i)
+ *   out = linear(y)
+ *   v.push_back(out)
+ * loss = v.back()
+ */
+TEST(Backward, TestForLoop) {}
+
+int main(int argc, char** argv) {
+  std::vector<paddle::platform::Place> places;
+  places.emplace_back(paddle::platform::CPUPlace());
+  paddle::platform::DeviceContextPool::Init(places);
+
+  testing::InitGoogleTest(&argc, argv);
+  return RUN_ALL_TESTS();
+}