Merge pull request #768 from effigies/fix/numpy_casting_error

FIX/TEST: Numpy casting rules have gotten more strict, raise different exception

Author: effigies

nibabel/tests/test_volumeutils.py

@@ -700,7 +700,7 @@ def test_a2f_non_numeric():
     # Some versions of numpy can cast structured types to float, others not
     try:
         arr.astype(float)
-    except ValueError:
+    except (TypeError, ValueError):
         pass
     else:
         back_arr = write_return(arr, fobj, float)