Merge pull request #16424 from czgdp1807:issue-16370

* fixed Split layer in ONNXImporter

* added test for fix of split layer

* fixed tests for Split layer

* applied reviews

* updated tests

* fixed paths in tests

modules/dnn/src/onnx/onnx_importer.cpp

@@ -484,6 +484,8 @@ void ONNXImporter::populateNet(Net dstNet)
             layerParams.set("end", DictValue::arrayInt(&end[0], end.size()));
          }
         else if (layer_type == "Split")
+        {
+            if (layerParams.has("split"))
             {
                 DictValue splits = layerParams.get("split");
                 const int numSplits = splits.size();
@@ -495,6 +497,11 @@ void ONNXImporter::populateNet(Net dstNet)
                     slicePoints[i] = slicePoints[i - 1] + splits.get<int>(i - 1);
                 }
                 layerParams.set("slice_point", DictValue::arrayInt(&slicePoints[0], slicePoints.size()));
+            }
+            else
+            {
+                layerParams.set("num_split", node_proto.output_size());
+            }
             layerParams.type = "Slice";
         }
         else if (layer_type == "Add" || layer_type == "Sum")

modules/dnn/test/test_onnx_importer.cpp

@@ -386,6 +386,18 @@ TEST_P(Test_ONNX_layers, ReduceL2)
     testONNXModels("reduceL2");
 }
 
+TEST_P(Test_ONNX_layers, Split)
+{
+    if (backend == DNN_BACKEND_INFERENCE_ENGINE_NN_BUILDER_2019)
+        applyTestTag(CV_TEST_TAG_DNN_SKIP_IE_NN_BUILDER);
+    if (backend == DNN_BACKEND_INFERENCE_ENGINE_NGRAPH)
+        applyTestTag(CV_TEST_TAG_DNN_SKIP_IE_NGRAPH);
+    testONNXModels("split_1");
+    testONNXModels("split_2");
+    testONNXModels("split_3");
+    testONNXModels("split_4");
+}
+
 TEST_P(Test_ONNX_layers, Slice)
 {
 #if defined(INF_ENGINE_RELEASE) && INF_ENGINE_VER_MAJOR_LT(2019010000)