Skip cpp tests if CUDA not available.

Signed-off-by: Edward Z. Yang <ezyang@fb.com>
diff --git a/test/test_jit.py b/test/test_jit.py
index 2bfbc34..3de9903 100644
--- a/test/test_jit.py
+++ b/test/test_jit.py
@@ -613,6 +613,7 @@
         assert(torch.equal(torch.ones([2, 2]), t_node.t("a")))
         self.assertExpected(str(g2))
 
+    @unittest.skipIf(not torch.cuda.is_available(), "cpp tests require CUDA")
     def test_cpp(self):
         torch._C._jit_run_cpp_tests()