@Test
    public void testWithMissingExplicitLanguageOnExistingWord() {
        var existingWord = "hello";
        var explicitLanguage = Language.ITALIAN;
        var result = searchWord(
                existingWord,
                Optional.of(explicitLanguage),
                Optional.empty(),
                Optional.empty(),
                Optional.empty()
        );

        var resultWord = getFirstWord(result);
        assertEquals(Optional.empty(), resultWord.getDocumentFrequency());

        var errorMessage = getErrorMessage(result);
        assertEquals("No significance model available for set language ITALIAN", errorMessage);
    }
Tests significance term in the search chain.

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