TreeMultimap<String, Integer> empty = TreeMultimap.create();
    TreeMultimap<String, Integer> filled = TreeMultimap.create();
    filled.put("a", 1);
    filled.put("a", 2);
    filled.put("b", 2);
    filled.put("c", 3);
    CollectorTester.of(collector, equivalence)
        .expectCollects(empty)
        .expectCollects(
            filled, mapEntry("a", 1), mapEntry("a", 2), mapEntry("b", 2), mapEntry("c", 3));
  }

    }
  }

  @GwtIncompatible // isPrime is GWT-incompatible
  public void testIsPrimeManyConstants() {
    // Test the thorough test inputs, which also includes special constants in the Miller-Rabin
    // tests.
    for (long l : POSITIVE_LONG_CANDIDATES) {
      assertEquals(BigInteger.valueOf(l).isProbablePrime(100), LongMath.isPrime(l));
    }
  }