Further fixes and tweaks for inputsplitter.

IPython/core/inputsplitter.py

@@ -587,8 +587,6 b' class InputSplitter(object):'
 
         If input lines are not newline-terminated, a newline is automatically
         appended."""
-        if not isinstance(lines, unicode):
-            lines = lines.decode(self.encoding)
         
         if buffer is None:
             buffer = self._buffer
@@ -600,7 +598,7 b' class InputSplitter(object):'
         setattr(self, store, self._set_source(buffer))
 
     def _set_source(self, buffer):
-        return ''.join(buffer)
+        return u''.join(buffer)
 
 
 #-----------------------------------------------------------------------------

IPython/core/tests/test_inputsplitter.py

@@ -364,7 +364,7 b' class InputSplitterTestCase(unittest.TestCase):'
     def test_unicode(self):
         self.isp.push(u"Pérez")
         self.isp.push(u'\xc3\xa9')
-        self.isp.push("u'\xc3\xa9'")
+        self.isp.push(u"u'\xc3\xa9'")
 
 class InteractiveLoopTestCase(unittest.TestCase):
     """Tests for an interactive loop like a python shell.