assertTrue(str.contains("RelevanceEvaluationResult"));
        assertTrue(str.contains("doc1"));
        assertTrue(str.contains("doc2"));
    }

    @Test
    public void test_noRelevantResults_toString() {
        RelevanceEvaluationResult result = RelevanceEvaluationResult.noRelevantResults();

        String str = result.toString();
        assertNotNull(str);