Add simple smoketest for page._detect_screen_size.

IPython/core/tests/test_page.py

@@ -0,0 +1,19 b''
+#-----------------------------------------------------------------------------
+#  Copyright (C) 2010 The IPython Development Team.
+#
+#  Distributed under the terms of the BSD License.
+#
+#  The full license is in the file COPYING.txt, distributed with this software.
+#-----------------------------------------------------------------------------
+import io
+
+from IPython.core import page
+
+def test_detect_screen_size():
+    """Simple smoketest for page._detect_screen_size."""
+    try:
+        page._detect_screen_size(True, 25)
+    except (TypeError, io.UnsupportedOperation):
+        # This can happen in the test suite, because stdout may not have a
+        # fileno.
+        pass

IPython/core/page.py

@@ -31,6 +31,8 b' import re'
 import sys
 import tempfile
 
+from io import UnsupportedOperation
+
 from IPython.core import ipapi
 from IPython.core.error import TryNext
 from IPython.utils.cursesimport import use_curses
@@ -180,7 +182,7 b' def page(strng, start=0, screen_lines=0, pager_cmd=None):'
     if screen_lines <= 0:
         try:
             screen_lines += _detect_screen_size(use_curses, screen_lines_def)
-        except Exception:
+        except (TypeError, UnsupportedOperation):
             print >>io.stdout, str_toprint
             return