added test to fix import error when cuda is not available

theano/sandbox/cuda/cusolver.py

@@ -3,10 +3,13 @@ from __future__ import absolute_import, division, print_function
 import pkg_resources
 import theano
 
-from theano.sandbox.cuda import CudaNdarray, GpuOp
+from theano.sandbox.cuda import GpuOp, cuda_available
 from theano.sandbox.cuda.basic_ops import as_cuda_ndarray_variable
 from theano.sandbox.cuda.type import CudaNdarrayType
 
+if cuda_available:
+    from theano.sandbox.cuda import CudaNdarray
+
 try:
     from theano.sandbox.cuda import cuda_ndarray
     dimshuffle = cuda_ndarray.cuda_ndarray.dimshuffle