FIX: Better testing

Author: larsoner

nibabel/tests/test_viewers.py

@@ -10,11 +10,6 @@
 import numpy as np
 from collections import namedtuple as nt
 
-try:
-    import matplotlib
-    matplotlib.use('agg')
-except Exception:
-    pass
 
 from ..optpkg import optional_package
 from ..viewers import OrthoSlicer3D
@@ -24,13 +19,16 @@
 
 from nose.tools import assert_raises
 
-plt, has_mpl = optional_package('matplotlib.pyplot')[:2]
+matplotlib, has_mpl = optional_package('matplotlib')[:2]
 needs_mpl = skipif(not has_mpl, 'These tests need matplotlib')
+if has_mpl:
+    matplotlib.use('Agg')
 
 
 @needs_mpl
 def test_viewer():
     # Test viewer
+    plt = optional_package('matplotlib.pyplot')[0]
     a = np.sin(np.linspace(0, np.pi, 20))
     b = np.sin(np.linspace(0, np.pi*5, 30))
     data = (np.outer(a, b)[..., np.newaxis] * a)[:, :, :, np.newaxis]

nibabel/viewers.py

@@ -11,10 +11,6 @@
 from .optpkg import optional_package
 from .orientations import aff2axcodes, axcodes2ornt
 
-plt, _, _ = optional_package('matplotlib.pyplot')
-mpl_img, _, _ = optional_package('matplotlib.image')
-mpl_patch, _, _ = optional_package('matplotlib.patches')
-
 
 class OrthoSlicer3D(object):
     """Orthogonal-plane slicer.
@@ -59,6 +55,12 @@ def __init__(self, data, affine=None, axes=None, cmap='gray',
         figsize : tuple
             Figure size (in inches) to use if axes are None.
         """
+        # Nest imports so that matplotlib.use() has the appropriate
+        # effect in testing
+        plt, _, _ = optional_package('matplotlib.pyplot')
+        mpl_img, _, _ = optional_package('matplotlib.image')
+        mpl_patch, _, _ = optional_package('matplotlib.patches')
+
         data = np.asanyarray(data)
         if data.ndim < 3:
             raise ValueError('data must have at least 3 dimensions')
@@ -200,11 +202,13 @@ def __init__(self, data, affine=None, axes=None, cmap='gray',
     def show(self):
         """Show the slicer in blocking mode; convenience for ``plt.show()``
         """
+        plt, _, _ = optional_package('matplotlib.pyplot')
         plt.show()
 
     def close(self):
         """Close the viewer figures
         """
+        plt, _, _ = optional_package('matplotlib.pyplot')
         for f in self._figs:
             plt.close(f)
         for link in self._links: