} catch (IllegalStateException expected) {
    } finally {
      Providers.setProviderList(providers);
    }
  }

  public void testMultipleUpdates() throws Exception {
    Mac mac = Mac.getInstance("HmacSHA1");
    mac.init(SHA1_KEY);
    mac.update("hello".getBytes(UTF_8));
    mac.update("world".getBytes(UTF_8));

    assertEquals(
        HashCode.fromBytes(mac.doFinal()),

    } catch (IllegalStateException expected) {
    } finally {
      Providers.setProviderList(providers);
    }
  }

  public void testMultipleUpdates() throws Exception {
    Mac mac = Mac.getInstance("HmacSHA1");
    mac.init(SHA1_KEY);
    mac.update("hello".getBytes(UTF_8));
    mac.update("world".getBytes(UTF_8));

    assertEquals(
        HashCode.fromBytes(mac.doFinal()),

  Locale generateLocale() {
    return pickInstance(Locale.getAvailableLocales(), Locale.US);
  }

  @Generates
  Currency generateCurrency() {
    return pickInstance(Currency.getAvailableCurrencies(), Currency.getInstance(Locale.US));
  }

  // common.base
  @Empty
  <T> com.google.common.base.Optional<T> generateGoogleOptional() {
    return com.google.common.base.Optional.absent();
  }

  @Generates

          .put(MatchResult.class, createMatchResult())
          .put(TimeUnit.class, TimeUnit.SECONDS)
          .put(Charset.class, Charsets.UTF_8)
          .put(Currency.class, Currency.getInstance(Locale.US))
          .put(Locale.class, Locale.US)
          .put(Optional.class, Optional.empty())
          .put(OptionalInt.class, OptionalInt.empty())
          .put(OptionalLong.class, OptionalLong.empty())

          .put(MatchResult.class, createMatchResult())
          .put(TimeUnit.class, TimeUnit.SECONDS)
          .put(Charset.class, Charsets.UTF_8)
          .put(Currency.class, Currency.getInstance(Locale.US))
          .put(Locale.class, Locale.US)
          .put(UUID.class, UUID.randomUUID())
          // common.base
          .put(CharMatcher.class, CharMatcher.none())

  Locale generateLocale() {
    return pickInstance(Locale.getAvailableLocales(), Locale.US);
  }

  @Generates
  Currency generateCurrency() {
    return pickInstance(Currency.getAvailableCurrencies(), Currency.getInstance(Locale.US));
  }

  @Empty
  <T> Optional<T> generateJavaOptional() {
    return Optional.empty();
  }

  @Generates
  <T> Optional<T> generateJavaOptional(T value) {

  private <T> T getDummyValue(TypeToken<T> type) {
    Class<? super T> rawType = type.getRawType();
    @SuppressWarnings("unchecked") // Assume all default values are generics safe.
    T defaultValue = (T) defaultValues.getInstance(rawType);
    if (defaultValue != null) {
      return defaultValue;
    }
    @SuppressWarnings("unchecked") // ArbitraryInstances always returns generics-safe dummies.

    // We assume that all defaults are generics-safe, even if they aren't,
    // we take the risk.
    @SuppressWarnings("unchecked")
    T defaultValue = (T) defaults.getInstance(type.getRawType());
    if (defaultValue != null) {
      return defaultValue;
    }
    @SuppressWarnings("unchecked") // All arbitrary instances are generics-safe

    // We assume that all defaults are generics-safe, even if they aren't,
    // we take the risk.
    @SuppressWarnings("unchecked")
    T defaultValue = (T) defaults.getInstance(type.getRawType());
    if (defaultValue != null) {
      return defaultValue;
    }
    @SuppressWarnings("unchecked") // All arbitrary instances are generics-safe

  private <T> T getDummyValue(TypeToken<T> type) {
    Class<? super T> rawType = type.getRawType();
    @SuppressWarnings("unchecked") // Assume all default values are generics safe.
    T defaultValue = (T) defaultValues.getInstance(rawType);
    if (defaultValue != null) {
      return defaultValue;
    }
    @SuppressWarnings("unchecked") // ArbitraryInstances always returns generics-safe dummies.