Backport PR #2668: pylab_not_importable: Catch all exceptions, not just RuntimeErrors.

This catches situations when `pylab` isn't installed or fails for another
reason like:

  ImportError: No module named backend_tkagg

Closes gh-2646.

IPython/lib/tests/test_irunner_pylab_magic.py

@@ -1,118 +1,118 b''
 """Test suite for pylab_import_all magic
 Modified from the irunner module but using regex.
 """
 
 # Global to make tests extra verbose and help debugging
 VERBOSE = True
 
 # stdlib imports
 import StringIO
 import sys
 import unittest
 import re
 
 # IPython imports
 from IPython.lib import irunner
 from IPython.testing import decorators
 
 def pylab_not_importable():
-    """Test if importing pylab fails with RuntimeError (true when having no display)"""
+    """Test if importing pylab fails. (For example, when having no display)"""
     try:
         import pylab
         return False
-    except RuntimeError:
+    except:
         return True
 
 # Testing code begins
 class RunnerTestCase(unittest.TestCase):
 
     def setUp(self):
         self.out = StringIO.StringIO()
         #self.out = sys.stdout
 
     def _test_runner(self,runner,source,output):
         """Test that a given runner's input/output match."""
 
         runner.run_source(source)
         out = self.out.getvalue()
         #out = ''
         # this output contains nasty \r\n lineends, and the initial ipython
         # banner.  clean it up for comparison, removing lines of whitespace
         output_l = [l for l in output.splitlines() if l and not l.isspace()]
         out_l = [l for l in out.splitlines() if l and not l.isspace()]
         mismatch  = 0
         if len(output_l) != len(out_l):
             message = ("Mismatch in number of lines\n\n"
                        "Expected:\n"
                        "~~~~~~~~~\n"
                        "%s\n\n"
                        "Got:\n"
                        "~~~~~~~~~\n"
                        "%s"
                        ) % ("\n".join(output_l), "\n".join(out_l))
             self.fail(message)
         for n in range(len(output_l)):
             # Do a line-by-line comparison
             ol1 = output_l[n].strip()
             ol2 = out_l[n].strip()
             if not re.match(ol1,ol2):
                 mismatch += 1
                 if VERBOSE:
                     print '<<< line %s does not match:' % n
                     print repr(ol1)
                     print repr(ol2)
                     print '>>>'
         self.assert_(mismatch==0,'Number of mismatched lines: %s' %
                      mismatch)
 
     @decorators.skipif_not_matplotlib
     @decorators.skipif(pylab_not_importable, "Likely a run without X.")
     def test_pylab_import_all_enabled(self):
         "Verify that plot is available when pylab_import_all = True"
         source = """
 from IPython.config.application import Application
 app = Application.instance()
 app.pylab_import_all = True
 pylab
 ip=get_ipython()
 'plot' in ip.user_ns
         """
         output = """
 In \[1\]: from IPython\.config\.application import Application
 In \[2\]: app = Application\.instance\(\)
 In \[3\]: app\.pylab_import_all = True
 In \[4\]: pylab
 ^Welcome to pylab, a matplotlib-based Python environment
 For more information, type 'help\(pylab\)'\.
 In \[5\]: ip=get_ipython\(\)
 In \[6\]: \'plot\' in ip\.user_ns
 Out\[6\]: True
 """
         runner = irunner.IPythonRunner(out=self.out)
         self._test_runner(runner,source,output)
 
     @decorators.skipif_not_matplotlib
     @decorators.skipif(pylab_not_importable, "Likely a run without X.")
     def test_pylab_import_all_disabled(self):
         "Verify that plot is not available when pylab_import_all = False"
         source = """
 from IPython.config.application import Application
 app = Application.instance()
 app.pylab_import_all = False
 pylab
 ip=get_ipython()
 'plot' in ip.user_ns
         """
         output = """
 In \[1\]: from IPython\.config\.application import Application
 In \[2\]: app = Application\.instance\(\)
 In \[3\]: app\.pylab_import_all = False
 In \[4\]: pylab
 ^Welcome to pylab, a matplotlib-based Python environment
 For more information, type 'help\(pylab\)'\.
 In \[5\]: ip=get_ipython\(\)
 In \[6\]: \'plot\' in ip\.user_ns
 Out\[6\]: False
 """
         runner = irunner.IPythonRunner(out=self.out)
         self._test_runner(runner,source,output)