fix lite unit test. (#29233)

paddle/fluid/inference/lite/test_engine.cc

@@ -29,6 +29,7 @@ namespace inference {
 namespace lite {
 
 using inference::lite::AddTensorToBlockDesc;
+using paddle::inference::lite::AddFetchListToBlockDesc;
 using inference::lite::CreateTensor;
 using inference::lite::serialize_params;
 
@@ -65,7 +66,7 @@ void make_fake_model(std::string* model, std::string* param) {
   AddTensorToBlockDesc(block_, "x", std::vector<int64_t>({2, 4}), true);
   AddTensorToBlockDesc(block_, "y", std::vector<int64_t>({2, 4}), true);
   AddTensorToBlockDesc(block_, "z", std::vector<int64_t>({2, 4}), false);
-  AddTensorToBlockDesc(block_, "out", std::vector<int64_t>({2, 4}), false);
+  AddFetchListToBlockDesc(block_, "out");
 
   *block_->add_ops() = *feed0->Proto();
   *block_->add_ops() = *feed1->Proto();

paddle/fluid/operators/lite/lite_engine_op_test.cc

@@ -25,6 +25,7 @@
 USE_NO_KERNEL_OP(lite_engine)
 
 using paddle::inference::lite::AddTensorToBlockDesc;
+using paddle::inference::lite::AddFetchListToBlockDesc;
 using paddle::inference::lite::CreateTensor;
 using paddle::inference::lite::serialize_params;
 namespace paddle {
@@ -60,7 +61,7 @@ TEST(LiteEngineOp, engine_op) {
   AddTensorToBlockDesc(block_, "x", std::vector<int64_t>({2, 4}), true);
   AddTensorToBlockDesc(block_, "y", std::vector<int64_t>({2, 4}), true);
   AddTensorToBlockDesc(block_, "z", std::vector<int64_t>({2, 4}), false);
-  AddTensorToBlockDesc(block_, "out", std::vector<int64_t>({2, 4}), false);
+  AddFetchListToBlockDesc(block_, "out");
   *block_->add_ops() = *feed1->Proto();
   *block_->add_ops() = *feed0->Proto();
   *block_->add_ops() = *elt_add->Proto();

paddle/fluid/operators/lite/ut_helper.h

@@ -42,6 +42,16 @@ void AddTensorToBlockDesc(framework::proto::BlockDesc* block,
   desc.SetPersistable(persistable);
   *var = *desc.Proto();
 }
+
+void AddFetchListToBlockDesc(framework::proto::BlockDesc* block,
+                             const std::string& name) {
+  using framework::proto::VarType;
+  auto* var = block->add_vars();
+  framework::VarDesc desc(name);
+  desc.SetType(VarType::FETCH_LIST);
+  *var = *desc.Proto();
+}
+
 void serialize_params(std::string* str, framework::Scope* scope,
                       const std::vector<std::string>& params) {
   std::ostringstream os;