skip writable io if nixio not on machine

Author: zm711

neo/test/iotest/test_get_io.py

@@ -1,6 +1,12 @@
 from pathlib import Path
 from tempfile import TemporaryDirectory
 from neo.io import get_io, list_candidate_ios, NixIO
+import pytest
+try:
+    import nixio
+    HAVE_NIX = True
+except:
+    HAVE_NIX = False
 
 
 def test_list_candidate_ios_non_existant_file():
@@ -28,7 +34,7 @@ def test_list_candidate_ios_filename_stub():
 
         assert NixIO in ios
 
-
+@pytest.mark.skipif(not HAVE_NIX, reason='Need nixio in order to return NixIO class')
 def test_get_io_non_existant_file_writable_io():
     # use nixio for testing with writable io
     non_existant_file = Path("non_existant_file.nix")