Add failing test for #822, will be fixed next

IPython/core/tests/test_interactiveshell.py

@@ -199,6 +199,13 b' class InteractiveShellTestCase(unittest.TestCase):'
         assert ip.user_ns['b'] == 12
         ip.reset()
 
+    def test_var_expand(self):
+        ip = get_ipython()
+        ip.user_ns['f'] = u'Ca\xc3\xb1o'
+        # This should not raise any exception:
+        ip.var_expand(u'echo $f')
+
+
 class TestSafeExecfileNonAsciiPath(unittest.TestCase):
 
     def setUp(self):