docBoostMatcher.setBoostExpression("10");
        assertEquals(0.0f, docBoostMatcher.getValue(null));
    }

    @Test
    public void test_getValue_emptyMap() {
        final DocBoostMatcher docBoostMatcher = new DocBoostMatcher();
        docBoostMatcher.setBoostExpression("10");
        assertEquals(0.0f, docBoostMatcher.getValue(new HashMap<>()));
    }