@Test(expected = IllegalArgumentException.class)
public void getExpressionMethodDeclarationUnknownExpression() {

    Expression expression = new Expression() {
        @Override
        public VisitorAction accept(Visitor visitor) {
            return null;
        }
    };
    DerivedFieldFunctionUtils.getExpressionMethodDeclaration(expression, DataType.STRING, new AtomicInteger());
}