assertEquals(Integer.valueOf(20), map.get(10));
    assertEquals(Integer.valueOf(0), map.get(20));
    assertEquals(Integer.valueOf(1), map.get(30));
    assertEquals(Integer.valueOf(2), map.get(54));
    assertEquals(Integer.valueOf(3), map.get(443));
    assertEquals(Integer.valueOf(4), map.get(1));
    assertEquals(Integer.valueOf(5), cache.get(6));

    }
  }

  public void testGCD() {
    for (int a : POSITIVE_INTEGER_CANDIDATES) {
      for (int b : POSITIVE_INTEGER_CANDIDATES) {
        assertEquals(valueOf(a).gcd(valueOf(b)), valueOf(IntMath.gcd(a, b)));
      }
    }
  }

  public void testGCDZero() {
    for (int a : POSITIVE_INTEGER_CANDIDATES) {
      assertEquals(a, IntMath.gcd(a, 0));

      }
    }
  }

  public void testGCDExhaustive() {
    for (long a : POSITIVE_LONG_CANDIDATES) {
      for (long b : POSITIVE_LONG_CANDIDATES) {
        assertEquals(valueOf(a).gcd(valueOf(b)), valueOf(LongMath.gcd(a, b)));
      }
    }
  }

  @GwtIncompatible // TODO
  public void testGCDZero() {
    for (long a : POSITIVE_LONG_CANDIDATES) {
      assertEquals(a, LongMath.gcd(a, 0));

    }
  }

  public void testGCD() {
    for (int a : POSITIVE_INTEGER_CANDIDATES) {
      for (int b : POSITIVE_INTEGER_CANDIDATES) {
        assertEquals(valueOf(a).gcd(valueOf(b)), valueOf(IntMath.gcd(a, b)));
      }
    }
  }

  public void testGCDZero() {
    for (int a : POSITIVE_INTEGER_CANDIDATES) {
      assertEquals(a, IntMath.gcd(a, 0));

          .add(doubleConversionTest + i);
      BigInteger bigI = BigInteger.valueOf(i);
      testBigIntegersBuilder
          .add(bigI)
          .add(BigInteger.valueOf(Long.MAX_VALUE).add(bigI))
          .add(BigInteger.valueOf(Long.MIN_VALUE).add(bigI))
          .add(BigInteger.valueOf(Integer.MAX_VALUE).add(bigI))
          .add(BigInteger.valueOf(Integer.MIN_VALUE).add(bigI))
          .add(BigInteger.ONE.shiftLeft(63).add(bigI))

          .add(doubleConversionTest + i);
      BigInteger bigI = BigInteger.valueOf(i);
      testBigIntegersBuilder
          .add(bigI)
          .add(BigInteger.valueOf(Long.MAX_VALUE).add(bigI))
          .add(BigInteger.valueOf(Long.MIN_VALUE).add(bigI))
          .add(BigInteger.valueOf(Integer.MAX_VALUE).add(bigI))
          .add(BigInteger.valueOf(Integer.MIN_VALUE).add(bigI))
          .add(BigInteger.ONE.shiftLeft(63).add(bigI))

      return addUnconditionalHolder(name, String.valueOf(value));
    }

    /**
     * Adds a name/value pair to the formatted output in {@code name=value} format.
     *
     * @since 18.0 (since 11.0 as {@code Objects.ToStringHelper.add()}).
     */
    @CanIgnoreReturnValue
    public ToStringHelper add(String name, char value) {
      return addUnconditionalHolder(name, String.valueOf(value));
    }

    /**

    assertEquals(Integer.valueOf(0), ArbitraryInstances.get(int.class));
    assertEquals(Integer.valueOf(0), ArbitraryInstances.get(Integer.class));
    assertEquals(Long.valueOf(0), ArbitraryInstances.get(long.class));
    assertEquals(Long.valueOf(0), ArbitraryInstances.get(Long.class));
    assertEquals(Float.valueOf(0), ArbitraryInstances.get(float.class));

        denominatorAccum *= q;
        numeratorBits += bits;
      }
    }
    return accum
        .multiply(BigInteger.valueOf(numeratorAccum))
        .divide(BigInteger.valueOf(denominatorAccum));
  }

  // Returns true if BigInteger.valueOf(x.longValue()).equals(x).
  @GwtIncompatible // TODO
  static boolean fitsInLong(BigInteger x) {
    return x.bitLength() <= Long.SIZE - 1;
  }

    assertEquals(Integer.valueOf(5), reserialize(Suppliers.ofInstance(5)).get());
    assertEquals(
        Integer.valueOf(5),
        reserialize(Suppliers.compose(Functions.identity(), Suppliers.ofInstance(5))).get());
    assertEquals(Integer.valueOf(5), reserialize(Suppliers.memoize(Suppliers.ofInstance(5))).get());
    assertEquals(
        Integer.valueOf(5),