private void test(final Map<String, Object> attributeMap,
                      final ExpressionOperator expression,
                      final boolean outcome) {
        final ExpressionMatcher expressionMatcher = new ExpressionMatcher(
                FIELD_MAP,
                null,
                null,
                DateTimeSettings.builder().build());
        assertThat(expressionMatcher.match(attributeMap, expression))
                .isEqualTo(outcome);
    }
This ought to behave in a consistent way with CommonExpressionMapper
stroom-search/stroom-expression-matcher/src/test/java/stroom/expression/matcher/TestExpressionMatcher.java