TST: QApplication doesn't quit early enough with PySide.

Fixes  #1628.  This commits adds a check in tests, to see if there's
already a QApplication and use it, instead of creating a new one each
time.

IPython/frontend/qt/console/tests/test_console_widget.py

@@ -1,40 +1,42 b''
 # Standard library imports
 import unittest
 
 # System library imports
 from IPython.external.qt import QtGui
 
 # Local imports
 from IPython.frontend.qt.console.console_widget import ConsoleWidget
 
 
 class TestConsoleWidget(unittest.TestCase):
 
     @classmethod
     def setUpClass(cls):
         """ Create the application for the test case.
         """
-        cls._app = QtGui.QApplication([])
+        cls._app = QtGui.QApplication.instance()
+        if cls._app is None:
+            cls._app = QtGui.QApplication([])
         cls._app.setQuitOnLastWindowClosed(False)
 
     @classmethod
     def tearDownClass(cls):
         """ Exit the application.
         """
         QtGui.QApplication.quit()
 
     def test_special_characters(self):
         """ Are special characters displayed correctly?
         """
         w = ConsoleWidget()
         cursor = w._get_prompt_cursor()
 
         test_inputs = ['xyz\b\b=\n', 'foo\b\nbar\n', 'foo\b\nbar\r\n', 'abc\rxyz\b\b=']
         expected_outputs = [u'x=z\u2029', u'foo\u2029bar\u2029', u'foo\u2029bar\u2029', 'x=z']
         for i, text in enumerate(test_inputs):
             w._insert_plain_text(cursor, text)
             cursor.select(cursor.Document)
             selection = cursor.selectedText()
             self.assertEquals(expected_outputs[i], selection)
             # clear all the text
             cursor.insertText('')

IPython/frontend/qt/console/tests/test_kill_ring.py

@@ -1,83 +1,85 b''
 # Standard library imports
 import unittest
 
 # System library imports
 from IPython.external.qt import QtCore, QtGui
 
 # Local imports
 from IPython.frontend.qt.console.kill_ring import KillRing, QtKillRing
 
 
 class TestKillRing(unittest.TestCase):
 
     @classmethod
     def setUpClass(cls):
         """ Create the application for the test case.
         """
-        cls._app = QtGui.QApplication([])
+        cls._app = QtGui.QApplication.instance()
+        if cls._app is None:
+            cls._app = QtGui.QApplication([])
         cls._app.setQuitOnLastWindowClosed(False)
 
     @classmethod
     def tearDownClass(cls):
         """ Exit the application.
         """
         QtGui.QApplication.quit()
 
     def test_generic(self):
         """ Does the generic kill ring work?
         """
         ring = KillRing()
         self.assert_(ring.yank() is None)
         self.assert_(ring.rotate() is None)
 
         ring.kill('foo')
         self.assertEqual(ring.yank(), 'foo')
         self.assert_(ring.rotate() is None)
         self.assertEqual(ring.yank(), 'foo')
 
         ring.kill('bar')
         self.assertEqual(ring.yank(), 'bar')
         self.assertEqual(ring.rotate(), 'foo')
 
         ring.clear()
         self.assert_(ring.yank() is None)
         self.assert_(ring.rotate() is None)
 
     def test_qt_basic(self):
         """ Does the Qt kill ring work?
         """
         text_edit = QtGui.QPlainTextEdit()
         ring = QtKillRing(text_edit)
 
         ring.kill('foo')
         ring.kill('bar')
         ring.yank()
         ring.rotate()
         ring.yank()
         self.assertEqual(text_edit.toPlainText(), 'foobar')
 
         text_edit.clear()
         ring.kill('baz')
         ring.yank()
         ring.rotate()
         ring.rotate()
         ring.rotate()
         self.assertEqual(text_edit.toPlainText(), 'foo')
 
     def test_qt_cursor(self):
         """ Does the Qt kill ring maintain state with cursor movement?
         """
         text_edit = QtGui.QPlainTextEdit()
         ring = QtKillRing(text_edit)
         
         ring.kill('foo')
         ring.kill('bar')
         ring.yank()
         text_edit.moveCursor(QtGui.QTextCursor.Left)
         ring.rotate()
         self.assertEqual(text_edit.toPlainText(), 'bar')
 
 
 if __name__ == '__main__':
     import nose
     nose.main()