Added unit test for volume_slice + generated image

docs/source/mayavi/mlab_3d_plotting_functions.rst

@@ -165,7 +165,7 @@ module.
                   described by three 3D arrays giving the ``u``,
                   ``v``, ``w`` components on a grid.
 
-|volume_slice|    :func:`volume_slice`
+|slice|           :func:`volume_slice`
                   |hack|
                   Plots an interactive image plane sliced through
                   volumetric data.
@@ -188,10 +188,11 @@ module.
 .. |flow| image:: generated_images/enthought_mayavi_mlab_flow.jpg
      :scale: 50
 
-.. |volume_slice| image:: generated_images/enthought_mayavi_mlab_volume_slice.jpg
+.. |slice| image:: generated_images/enthought_mayavi_mlab_volume_slice.jpg
      :scale: 50
 
-  .. note::
+
+.. note::
 
     Many richer visualizations can be created by assembling data sources
     filters and modules. See the

mayavi/tests/test_mlab_integration.py

@@ -90,6 +90,7 @@ def test_mlab_source(self):
             (mlab.pipeline.scalar_field, ),
             (mlab.pipeline.scalar_field, mlab.pipeline.image_plane_widget),
             (mlab.contour3d, ),
+            (mlab.volume_slice, ),
             (mlab.points3d, ), )
         data = np.random.random((3, 3, 3))
         for pipeline in pipelines:
@@ -335,6 +336,12 @@ def test_imshow_colormap(self):
         with self.assertTraitChanges(actor, 'pipeline_changed'):
             actor.module_manager.scalar_lut_manager.lut_mode = 'jet'
 
+    def test_volume_slice(self):
+        x, y, z = np.ogrid[-5:5:20j, -5:5:20j, -5:5:20j]
+        scalars = x * x * 0.5 + y * y + z * z * 2.0
+        ipw = mlab.volume_slice(scalars, plane_orientation='y_axes')
+        self.assertEqual(ipw.ipw.plane_orientation, 'y_axes')
+
 
 ################################################################################
 # class `TestMlabModules`