FreshValueGenerator paramValues = new FreshValueGenerator();
    List<@Nullable Object> passedArgs = Lists.newArrayList();
    for (Class<?> paramType : method.getParameterTypes()) {
      passedArgs.add(paramValues.generateFresh(paramType));
    }
    return passedArgs.toArray();
  }

  /** Tests a single interaction against a method. */
  private static final class InteractionTester<T> extends AbstractInvocationHandler {

    FreshValueGenerator paramValues = new FreshValueGenerator();
    List<@Nullable Object> passedArgs = Lists.newArrayList();
    for (Class<?> paramType : method.getParameterTypes()) {
      passedArgs.add(paramValues.generateFresh(paramType));
    }
    return passedArgs.toArray();
  }

  /** Tests a single interaction against a method. */
  private static final class InteractionTester<T> extends AbstractInvocationHandler {