Add test for non-ascii characters in PlainTextFormatter

IPython/core/tests/test_interactiveshell.py

@@ -112,5 +112,11 b' class InteractiveShellTestCase(unittest.TestCase):'
         ip = get_ipython()
         ip.run_cell('!(true)\n', False)
         ip.run_cell('!(true)\n\n\n', False)
-
-
+    
+    def test_gh_597(self):
+        class Spam(object):
+          def __repr__(self):
+            return "\xe9"*50
+        import IPython.core.formatters
+        f = IPython.core.formatters.PlainTextFormatter()
+        f([Spam(),Spam()])