diff -up theano/tensor/tests/test_sort.py.orig theano/tensor/tests/test_sort.py
--- theano/tensor/tests/test_sort.py.orig	2019-08-23 20:46:06.243192142 +0200
+++ theano/tensor/tests/test_sort.py	2019-08-23 20:45:55.490214412 +0200
@@ -37,7 +37,7 @@ class Test_sort(unittest.TestCase):
 
     def test2(self):
         a = tensor.dmatrix()
-        axis = tensor.scalar()
+        axis = tensor.scalar(dtype="int64")
         w = sort(a, axis)
         f = theano.function([a, axis], w)
         for axis_val in 0, 1:
@@ -55,7 +55,7 @@ class Test_sort(unittest.TestCase):
 
     def test4(self):
         a = tensor.dmatrix()
-        axis = tensor.scalar()
+        axis = tensor.scalar(dtype="int64")
         l = sort(a, axis, "mergesort")
         f = theano.function([a, axis], l)
         for axis_val in 0, 1: