@Test
    public void testWithUnknownExplicitLanguageOnExistingWord() {
        var existingWord = "hello";
        var explicitLanguage = Optional.of(Language.UNKNOWN);

        var result = searchWord(
                existingWord,
                explicitLanguage,
                Optional.empty(),
                Optional.empty(),
                Optional.empty()
        );

        var resultWord = getFirstWord(result);
        var existingDocumentFrequency = getModelDocumentFrequencyWithEnglish(existingWord);
        assertEquals(existingDocumentFrequency, resultWord.getDocumentFrequency());
    }
Tests significance term in the search chain.

@author MariusArhaug
container-search/src/test/java/com/yahoo/search/significance/test/SignificanceSearcherTest.java