assertEquals(
        Integer.valueOf(5),
        reserialize(Suppliers.synchronizedSupplier(Suppliers.ofInstance(5))).get());
  }

  @J2ktIncompatible
  @GwtIncompatible // reflection
  public void testSuppliersNullChecks() throws Exception {
    new ClassSanityTester()
        .setDefault(Duration.class, Duration.ofSeconds(1))
        .forAllPublicStaticMethods(Suppliers.class)
        .testNulls();
  }