netCDF tests now skipped if library missing (closes #124)

testsuite/MDAnalysisTests/coordinates/test_netcdf.py

@@ -5,7 +5,7 @@
 
 from nose.plugins.attrib import attr
 from numpy.testing import (assert_equal, assert_array_almost_equal,
-                           assert_almost_equal, assert_raises)
+                           assert_almost_equal, assert_raises, dec)
 import tempdir
 from unittest import TestCase
 
@@ -14,8 +14,16 @@
 from MDAnalysisTests.coordinates.test_trj import _TRJReaderTest
 from MDAnalysisTests.coordinates.reference import (RefVGV,)
 
+def netcdf_missing():
+    try:
+        import netCDF4
+    except ImportError:
+        return True
+    else:
+        return False
 
 class TestNCDFReader(_TRJReaderTest, RefVGV):
+    @dec.skipif(netcdf_missing(), "Test skipped because netCDF is not available.")
     def setUp(self):
         self.universe = mda.Universe(PRMncdf, NCDF)
         self.prec = 3
@@ -38,6 +46,7 @@ class TestNCDFReader2(TestCase):
     Contributed by Albert Solernou
     """
 
+    @dec.skipif(netcdf_missing(), "Test skipped because netCDF is not available.")
     def setUp(self):
         self.u = mda.Universe(PFncdf_Top, PFncdf_Trj)
         self.prec = 3
@@ -94,6 +103,7 @@ def test_time_2(self):
 
 
 class TestNCDFWriter(TestCase, RefVGV):
+    @dec.skipif(netcdf_missing(), "Test skipped because netCDF is not available.")
     def setUp(self):
         self.universe = mda.Universe(PRMncdf, NCDF)
         self.prec = 6
@@ -211,6 +221,7 @@ def test_write_AtomGroup(self):
 class TestNCDFWriterVelsForces(TestCase):
     """Test writing NCDF trajectories with a mixture of options"""
 
+    @dec.skipif(netcdf_missing(), "Test skipped because netCDF is not available.")
     def setUp(self):
         self.tmpdir = tempdir.TempDir()
         self.outfile = self.tmpdir.name + '/ncdf-write-vels-force.ncdf'