Fix inline backend logic and avoid tests if mpl not available.

IPython/core/pylabtools.py

@@ -253,7 +253,7 b' def import_pylab(user_ns, import_all=True):'
         exec s in user_ns
 
 
-def configure_inline_backend(shell, user_ns=None):
+def configure_inline_support(shell, backend, user_ns=None):
     """Configure an IPython shell object for matplotlib use.
 
     Parameters
@@ -261,6 +261,8 b' def configure_inline_backend(shell, user_ns=None):'
     shell : InteractiveShell instance
       If None, this function returns immediately.
 
+    backend : matplotlib backend
+
     user_ns : dict
       A namespace where all configured variables will be placed.  If not given,
       the `user_ns` attribute of the shell object is used.
@@ -268,18 +270,26 b' def configure_inline_backend(shell, user_ns=None):'
     if shell is None:
         return
 
-    user_ns = shell.user_ns if user_ns is None else user_ns
-    
     # If using our svg payload backend, register the post-execution
     # function that will pick up the results for display.  This can only be
     # done with access to the real shell object.
+
+    # Note: if we can't load the inline backend, then there's no point
+    # continuing (such as in terminal-only shells in environments without
+    # zeromq available).
+    try:
     from IPython.zmq.pylab.backend_inline import InlineBackend
+    except ImportError:
+        return
+
+    user_ns = shell.user_ns if user_ns is None else user_ns
 
     cfg = InlineBackend.instance(config=shell.config)
     cfg.shell = shell
     if cfg not in shell.configurables:
         shell.configurables.append(cfg)
 
+    if backend == backends['inline']:
     from IPython.zmq.pylab.backend_inline import flush_figures
     from matplotlib import pyplot
     shell.register_post_execute(flush_figures)
@@ -323,10 +333,7 b' def pylab_activate(user_ns, gui=None, import_all=True, shell=None):'
     gui, backend = find_gui_and_backend(gui)
     activate_matplotlib(backend)
     import_pylab(user_ns, import_all)
-
-    # The inline backend is only used by GUI shells
-    if backend == backends['inline']:
-        configure_inline_backend(shell, backend, user_ns)
+    configure_inline_support(shell, backend, user_ns)
         
     print """
 Welcome to pylab, a matplotlib-based Python environment [backend: %s].

IPython/testing/iptest.py

@@ -238,8 +238,8 b' def make_exclude():'
         exclusions.append(ipjoin('parallel', 'tests', 'test_mongodb'))
 
     if not have['matplotlib']:
-        exclusions.extend([ipjoin('lib', 'pylabtools'),
-                           ipjoin('lib', 'tests', 'test_pylabtools')])
+        exclusions.extend([ipjoin('core', 'pylabtools'),
+                           ipjoin('core', 'tests', 'test_pylabtools')])
 
     if not have['tornado']:
         exclusions.append(ipjoin('frontend', 'html'))