Add simple test for non-ascii characters in system_raw call.

IPython/core/interactiveshell.py

@@ -2085,6 +2085,7 class InteractiveShell(SingletonConfigurable, Magic):
                 cmd = py3compat.unicode_to_str(cmd)
                 ec = os.system(cmd)
         else:
+            cmd = py3compat.unicode_to_str(cmd)
             ec = os.system(cmd)
         
         # We explicitly do NOT return the subprocess status code, because

IPython/core/tests/test_interactiveshell.py

@@ -220,3 +220,11 class TestSafeExecfileNonAsciiPath(unittest.TestCase):
         """Test safe_execfile with non-ascii path
         """
         _ip.shell.safe_execfile(self.fname, {}, raise_exceptions=True)
+
+
+class TestSystemRaw(unittest.TestCase):
+    def test_1(self):
+        """Test system_raw with non-ascii cmd
+        """
+        cmd = ur'''python -c "u'åäö'"   '''
+        _ip.shell.system_raw(cmd)