Mockito 从我在测试用例中的列表中为存根方法返回不同的值答案

【问题标题】：Mockito return different values for a stub method from a list i have in test caseMockito 从我在测试用例中的列表中为存根方法返回不同的值
【发布时间】：2020-07-08 18:43:16
【问题描述】：

在模拟存根方法以从列表返回的这一部分中，我得到了空指针异常。我的inputProvider 是一种模拟间谍方法。这个方法testCase被许多类似测试用例的测试方法调用。

private void testCase(String config, String orders, List<String> outputs){
        try {
            CoffeeMachineRunner machineRunner = new CoffeeMachineRunner();
            when(inputProvider.getConfigInput()).thenReturn(config);
            List<Order> orderList = getOrderFromJson(orders);
            Iterator<Order> it = orderList.iterator();
            when(inputProvider.hasNextInput()).thenAnswer(new Answer<Boolean>() {
                private Iterator<Order> iterator = it;
                @Override
                public Boolean answer(InvocationOnMock invocation) throws Throwable {
                    return iterator.hasNext();
                }
            });
            when(inputProvider.getNextInput()).thenAnswer(new Answer<Order>() {
                private Iterator<Order> iterator = it;
                @Override
                public Order answer(InvocationOnMock invocation) throws Throwable {
                    return iterator.next();
                }
            });
            machineRunner.simulate(inputProvider);
            assertStringIn(outputs, outContent.toString());
        } catch (Exception e) {
            assertTrue(false);
        }
    }

基本上，我如何在两个方法调用上使用共享迭代器从这个列表中返回一个值。 hasNext 和 getNext ?

【问题讨论】：

标签： java testing mockito

【解决方案1】：

尝试制作迭代器final并在答案中使用它

private void testCase(String config, String orders, List<String> outputs){
        try {
            CoffeeMachineRunner machineRunner = new CoffeeMachineRunner();
            when(inputProvider.getConfigInput()).thenReturn(config);
            List<Order> orderList = getOrderFromJson(orders);
            final Iterator<Order> iter = orderList.iterator();
            doAnswer(new Answer<Boolean>() {
                @Override
                public Boolean answer(InvocationOnMock invocation) throws Throwable {
                    return iter.hasNext();
                }
            }).when(inputProvider).hasNextInput();

            doAnswer(new Answer<Order>() {
                @Override
                public Order answer(InvocationOnMock invocation) throws Throwable {
                    return iter.next();
                }
            }).when(inputProvider).getNextInput();

            machineRunner.simulate(inputProvider);

            assertStringIn(outputs, outContent.toString());
        } catch (Exception e) {
            assertTrue(false);
        }
    }

从 JDK-8+ 使用 Lambda

private void testCase(String config, String orders, List<String> outputs){
        try {
            CoffeeMachineRunner machineRunner = new CoffeeMachineRunner();
            when(inputProvider.getConfigInput()).thenReturn(config);
            List<Order> orderList = getOrderFromJson(orders);
            final Iterator<Order> iter = orderList.iterator();

            doAnswer(invocation -> iter.hasNext()).when(inputProvider).hasNextInput();
            doAnswer(invocation -> iter.next()).when(inputProvider).getNextInput();

            machineRunner.simulate(inputProvider);

            assertStringIn(outputs, outContent.toString());
        } catch (Exception e) {
            assertTrue(false);
        }
    }

【讨论】：