@Test
    void testPhrase() {
        PhraseItem p = new PhraseItem();

        p.addItem(new WordItem("part"));
        p.addItem(new WordItem("of"));
        p.addItem(new WordItem("phrase"));
        assertEquals("\"part of phrase\"", p.toString());
    }
<p>Tests that the correct query language strings are generated for various
query trees.</p>

<p>The opposite direction is tested by
{@link com.yahoo.prelude.query.parser.test.ParseTestCase}.
Note that the query language statements produced by a query tree is a
subset of the statements accepted by the parser.</p>

@author bratseth
container-search/src/test/java/com/yahoo/prelude/query/test/QueryLanguageTestCase.java