def test_concat(self):
        def test_impl(n):
            df1 = pd.DataFrame({'key1': np.arange(n), 'A': np.arange(n) + 1.0})
            df2 = pd.DataFrame({'key2': n - np.arange(n), 'A': n + np.arange(n) + 1.0})
            df3 = pd.concat([df1, df2])
            return df3.A.sum() + df3.key2.sum()

        hpat_func = self.jit(test_impl)
        n = 11
        self.assertEqual(hpat_func(n), test_impl(n))
        self.assertEqual(count_array_REPs(), 0)
        self.assertEqual(count_parfor_REPs(), 0)
        n = 11111
        self.assertEqual(hpat_func(n), test_impl(n))