This test was failing as there are no bind values in the KerasSymbol and because of this whenever this symbol was evaluated in forward pass, we cannot conclude if its sparse or not.
We need a way in which we can check if tensor is sparse by adding an attribute to it (such as stype).
Enable sparse_concat test which was disabled in this PR - https://github.com/awslabs/keras-apache-mxnet/pull/177
This test was failing as there are no bind values in the KerasSymbol and because of this whenever this symbol was evaluated in forward pass, we cannot conclude if its sparse or not. We need a way in which we can check if tensor is sparse by adding an attribute to it (such as stype).