}

    /**
     * Sets the match expression used to determine if documents should be boosted.
     *
     * @param expression the match expression string
     */
    public void setMatchExpression(final String expression) {
        matchExpression = expression;
    }

        final DocBoostMatcher docBoostMatcher = new DocBoostMatcher();
        docBoostMatcher.setMatchExpression("true");
        assertFalse(docBoostMatcher.match(null));
    }

    @Test
    public void test_match_emptyMap() {
        final DocBoostMatcher docBoostMatcher = new DocBoostMatcher();
        docBoostMatcher.setMatchExpression("true");
        assertFalse(docBoostMatcher.match(new HashMap<>()));
    }

    @Test