@Test public void test1() {
        Stack<Object> stack = new Stack<>();
        stack.push("Hello");
        try {
            NotEqualsRule.getRule(stack);
            Assert.fail("Should have thrown IllegalArgumentException");
        } catch (IllegalArgumentException ignored) {
        }
    }
getRule() with only one entry on stack should throw IllegalArgumentException.
olv-core/src/test/java/pl/otros/logview/accept/query/org/apache/log4j/rule/NotEqualsRuleTest.java