@Test
public void invokePositionPositive() {

    FunctionTestUtil.assertResult(insertBeforeFunction.invoke(Collections.singletonList("test"), BigDecimal.ONE, null), Arrays.asList(null, "test"));
    FunctionTestUtil.assertResult(
            insertBeforeFunction.invoke(Arrays.asList("test", null, BigDecimal.ZERO), BigDecimal.valueOf(2), "testtt"),
            Arrays.asList("test", "testtt", null, BigDecimal.ZERO));
    FunctionTestUtil.assertResult(
            insertBeforeFunction.invoke(Arrays.asList("test", null, BigDecimal.ZERO), BigDecimal.valueOf(3), "testtt"),
            Arrays.asList("test", null, "testtt", BigDecimal.ZERO));
}