use testing decorators to enable tests on module availability

IPython/core/tests/test_pylabtools.py

@@ -1,154 +1,153 b''
 """Tests for pylab tools module.
 """
 #-----------------------------------------------------------------------------
 # Copyright (c) 2011, the IPython Development Team.
 #
 # Distributed under the terms of the Modified BSD License.
 #
 # The full license is in the file COPYING.txt, distributed with this software.
 #-----------------------------------------------------------------------------
 
 #-----------------------------------------------------------------------------
 # Imports
 #-----------------------------------------------------------------------------
 from __future__ import print_function
 
 # Stdlib imports
 
 # Third-party imports
 import matplotlib; matplotlib.use('Agg')
 import nose.tools as nt
 
 from matplotlib import pyplot as plt
 import numpy as np
 
 # Our own imports
 from IPython.core.interactiveshell import InteractiveShell
 from .. import pylabtools as pt
 
+from IPython.testing import decorators as dec
+
 #-----------------------------------------------------------------------------
 # Globals and constants
 #-----------------------------------------------------------------------------
 
 #-----------------------------------------------------------------------------
 # Local utilities
 #-----------------------------------------------------------------------------
 
 #-----------------------------------------------------------------------------
 # Classes and functions
 #-----------------------------------------------------------------------------
 
 def test_figure_to_svg():
     # simple empty-figure test
     fig = plt.figure()
     nt.assert_equal(pt.print_figure(fig, 'svg'), None)
 
     plt.close('all')
 
     # simple check for at least svg-looking output
     fig = plt.figure()
     ax = fig.add_subplot(1,1,1)
     ax.plot([1,2,3])
     plt.draw()
     svg = pt.print_figure(fig, 'svg')[:100].lower()
     nt.assert_in(b'doctype svg', svg)
 
-try:
-    from PIL import Image
-    def test_figure_to_jpg():
-        # simple check for at least jpg-looking output
-        fig = plt.figure()
-        ax = fig.add_subplot(1,1,1)
-        ax.plot([1,2,3])
-        plt.draw()
-        jpg = pt.print_figure(fig, 'jpg')[:100].lower()
-        assert jpg.startswith(b'\xff\xd8')
-except ImportError:
-    pass
[e-mail]_without("PIL.Image")
+def test_figure_to_jpg():
+    # simple check for at least jpg-looking output
+    fig = plt.figure()
+    ax = fig.add_subplot(1,1,1)
+    ax.plot([1,2,3])
+    plt.draw()
+    jpg = pt.print_figure(fig, 'jpg')[:100].lower()
+    assert jpg.startswith(b'\xff\xd8')
 
 
 def test_import_pylab():
     ip = get_ipython()
     ns = {}
     pt.import_pylab(ns, import_all=False)
     nt.assert_true('plt' in ns)
     nt.assert_equal(ns['np'], np)
 
 class TestPylabSwitch(object):
     class Shell(InteractiveShell):
         def enable_gui(self, gui):
             pass
     
     def setup(self):
         import matplotlib
         def act_mpl(backend):
             matplotlib.rcParams['backend'] = backend
 
         # Save rcParams since they get modified
         self._saved_rcParams = matplotlib.rcParams
         self._saved_rcParamsOrig = matplotlib.rcParamsOrig
         matplotlib.rcParams = dict(backend='Qt4Agg')
         matplotlib.rcParamsOrig = dict(backend='Qt4Agg')
 
         # Mock out functions
         self._save_am = pt.activate_matplotlib
         pt.activate_matplotlib = act_mpl
         self._save_ip = pt.import_pylab
         pt.import_pylab = lambda *a,**kw:None
         self._save_cis = pt.configure_inline_support
         pt.configure_inline_support = lambda *a,**kw:None
 
     def teardown(self):
         pt.activate_matplotlib = self._save_am
         pt.import_pylab = self._save_ip
         pt.configure_inline_support = self._save_cis
         import matplotlib
         matplotlib.rcParams = self._saved_rcParams
         matplotlib.rcParamsOrig = self._saved_rcParamsOrig
 
     def test_qt(self):
         s = self.Shell()
         gui, backend = s.enable_matplotlib(None)
         nt.assert_equal(gui, 'qt')
         nt.assert_equal(s.pylab_gui_select, 'qt')
 
         gui, backend = s.enable_matplotlib('inline')
         nt.assert_equal(gui, 'inline')
         nt.assert_equal(s.pylab_gui_select, 'qt')
 
         gui, backend = s.enable_matplotlib('qt')
         nt.assert_equal(gui, 'qt')
         nt.assert_equal(s.pylab_gui_select, 'qt')
 
         gui, backend = s.enable_matplotlib('inline')
         nt.assert_equal(gui, 'inline')
         nt.assert_equal(s.pylab_gui_select, 'qt')
 
         gui, backend = s.enable_matplotlib()
         nt.assert_equal(gui, 'qt')
         nt.assert_equal(s.pylab_gui_select, 'qt')
 
     def test_inline(self):
         s = self.Shell()
         gui, backend = s.enable_matplotlib('inline')
         nt.assert_equal(gui, 'inline')
         nt.assert_equal(s.pylab_gui_select, None)
 
         gui, backend = s.enable_matplotlib('inline')
         nt.assert_equal(gui, 'inline')
         nt.assert_equal(s.pylab_gui_select, None)
 
         gui, backend = s.enable_matplotlib('qt')
         nt.assert_equal(gui, 'qt')
         nt.assert_equal(s.pylab_gui_select, 'qt')
 
     def test_qt_gtk(self):
         s = self.Shell()
         gui, backend = s.enable_matplotlib('qt')
         nt.assert_equal(gui, 'qt')
         nt.assert_equal(s.pylab_gui_select, 'qt')
 
         gui, backend = s.enable_matplotlib('gtk')
         nt.assert_equal(gui, 'qt')
         nt.assert_equal(s.pylab_gui_select, 'qt')