updated doctests for the case vtk is not installed (typically python 3.0)

Author: oesteban

.travis.yml

@@ -44,12 +44,12 @@ install:
 # Add tvtk (PIL is required by blockcanvas)
 # Install mayavi (see https://github.com/enthought/mayavi/issues/271)
 - if [ ${TRAVIS_PYTHON_VERSION:0:1} == "2" ]; then
-  pip install http://effbot.org/downloads/Imaging-1.1.7.tar.gz
-  pip install -e git+https://github.com/enthought/etsdevtools.git#egg=etsdevtools
-  pip install -e git+https://github.com/enthought/blockcanvas.git#egg=blockcanvas
-  pip install -e git+https://github.com/enthought/etsproxy.git#egg=etsproxy
-  pip install https://github.com/dmsurti/mayavi/archive/4d4aaf315a29d6a86707dd95149e27d9ed2225bf.zip
-  pip install -e git+https://github.com/enthought/ets.git#egg=ets
+  pip install http://effbot.org/downloads/Imaging-1.1.7.tar.gz;
+  pip install -e git+https://github.com/enthought/etsdevtools.git#egg=etsdevtools;
+  pip install -e git+https://github.com/enthought/blockcanvas.git#egg=blockcanvas;
+  pip install -e git+https://github.com/enthought/etsproxy.git#egg=etsproxy;
+  pip install https://github.com/dmsurti/mayavi/archive/4d4aaf315a29d6a86707dd95149e27d9ed2225bf.zip;
+  pip install -e git+https://github.com/enthought/ets.git#egg=ets;
   fi
 - pip install -r requirements.txt  # finish remaining requirements
 - python setup.py install

nipype/algorithms/mesh.py

@@ -224,11 +224,18 @@ class ComputeMeshWarp(TVTKBaseInterface):
     Example
     -------
 
+    >>> from nipype.algorithms.mesh import have_tvtk
     >>> import nipype.algorithms.mesh as m
-    >>> dist = m.ComputeMeshWarp()
-    >>> dist.inputs.surface1 = 'surf1.vtk'
-    >>> dist.inputs.surface2 = 'surf2.vtk'
-    >>> res = dist.run()  # doctest: +SKIP
+    >>> if not have_tvtk:
+    ...     dist = m.ComputeMeshWarp()
+    Traceback (most recent call last):
+     ...
+    ImportError: This interface requires tvtk to run.
+    >>> else:
+    ...     dist = m.ComputeMeshWarp()
+    ...     dist.inputs.surface1 = 'surf1.vtk'
+    ...     dist.inputs.surface2 = 'surf2.vtk'
+    ...     res = dist.run()  # doctest: +SKIP
 
     """
 
@@ -355,12 +362,19 @@ class MeshWarpMaths(TVTKBaseInterface):
     Example
     -------
 
+    >>> from nipype.algorithms.mesh import have_tvtk
     >>> import nipype.algorithms.mesh as m
-    >>> mmath = m.MeshWarpMaths()
-    >>> mmath.inputs.in_surf = 'surf1.vtk'
-    >>> mmath.inputs.operator = 'surf2.vtk'
-    >>> mmath.inputs.operation = 'mul'
-    >>> res = mmath.run()  # doctest: +SKIP
+    >>> if not have_tvtk:
+    ...     mmath = m.MeshWarpMaths()
+    Traceback (most recent call last):
+     ...
+    ImportError: This interface requires tvtk to run.
+    >>> else:
+    ...     mmath = m.MeshWarpMaths()
+    ...     mmath.inputs.in_surf = 'surf1.vtk'
+    ...     mmath.inputs.operator = 'surf2.vtk'
+    ...     mmath.inputs.operation = 'mul'
+    ...     res = mmath.run()  # doctest: +SKIP
 
     """