} catch (NullPointerException e) {
            // Expected
        }
    }

    @Test
    public void test_encodeUrl_unicode() {
        assertEquals("%3F", DocumentUtil.encodeUrl("あ"));
        assertEquals("%3F%3F%3F", DocumentUtil.encodeUrl("あいう"));
    }

    @Test
    public void test_complex_document_structure() {
        Map<String, Object> doc = new HashMap<>();

    long nowNanos = System.nanoTime();
    if (name.equals("callStart")) {
      callStartNanos = nowNanos;
    }
    long elapsedNanos = nowNanos - callStartNanos;
    System.out.printf("%.3f %s%n", elapsedNanos / 1000000000d, name);
  }

  @Override public void callStart(Call call) {
    printEvent("callStart");
  }

  @Override public void callEnd(Call call) {
    printEvent("callEnd");
  }