diff -up MDAnalysis-0.18.0/MDAnalysisTests-0.18.0/MDAnalysisTests/utils/test_duecredits.py.orig MDAnalysis-0.18.0/MDAnalysisTests-0.18.0/MDAnalysisTests/utils/test_duecredits.py
--- MDAnalysis-0.18.0/MDAnalysisTests-0.18.0/MDAnalysisTests/utils/test_duecredits.py.orig	2018-04-15 21:57:08.000000001 +0200
+++ MDAnalysis-0.18.0/MDAnalysisTests-0.18.0/MDAnalysisTests/utils/test_duecredits.py	2018-07-02 16:42:56.949956938 +0200
@@ -28,6 +28,10 @@ import pytest
 # to work; duecredit must also be installed)
 import MDAnalysis as mda
 
+# duecredit itself is not needed in the name space but this is a
+# convenient way to skip all tests if duecredit is not installed
+# (see https://github.com/MDAnalysis/mdanalysis/issues/1906)
+pytest.importorskip('duecredit')
 
 @pytest.mark.skipif((os.environ.get('DUECREDIT_ENABLE', 'yes').lower()
                      in ('no', '0', 'false')),