@Test
    void testNullTracing() {
        Query q = new Query("?query=foo&traceLevel=2");
        assertEquals(2, q.getTrace().getLevel());
        q.trace(false, 2, "trace2 ", null);
        Set<String> traces = new HashSet<>();
        for (String trace : q.getContext(true).getTrace().traceNode().descendants(String.class))
            traces.add(trace);
        assertTrue(traces.contains("trace2 null"));
    }
Test that we get the last value if a parameter is assigned multiple times
container-search/src/test/java/com/yahoo/search/test/QueryTestCase.java