JMockit:如何调用MockUp的自定义方法

Question

我的应用程序使用FastScanner (基于BufferedReader)读取输入(请参阅问题的代码部分)。

如果我想在我的测试中替换输入，我应该模拟FastScanner (请看我问题的代码部分)。

问题： For each input I should make separate mockup.，如果我能在单个锁内切换输入，那就太棒了。

问题： How to add custom methods to JMockit MockUps and than call them? (看FastScanner模型的switchInput方法)

代码:本节是可选的，只为您更好地理解

FastScanner

protected static class FastScanner {
    BufferedReader br;
    StringTokenizer st;

    FastScanner(InputStream f) {
        br = new BufferedReader(new InputStreamReader(f));
    }

    String next() throws IOException {
        while (st == null || !st.hasMoreTokens()) {
            st = new StringTokenizer(br.readLine());
        }
        return st.nextToken();
    }

    int nextInt() throws IOException {
        return Integer.parseInt(next());
    }
} 

FastScanner MockUp：

new MockUp<FastScanner>() {

        private int[] input1 = new int[] {17, 2, 3, 1, 1, 1, 1, 1, 1, 3, 1, 1, 1, 1, 1, 1, 1, 3, 1, 1};
        private int[] input2 = new int[] {5, 2, 2, 3, 3, 3, 3, 3};
        private int[] input3 = new int[] {8, 2, 5, 1, 3, 1, 1, 1, 1, 3, 1};
        private byte toggler = 1;
        private byte pointer = 0;

        //HERE THE QUESTION: HOW CAN I CALL THIS METHOD
        public void switchInput() { 
            toggler++;
            pointer = 0;
        }

        @SuppressWarnings("unused")
        int nextInt() throws IOException {
            int[] input = null;
            switch (toggler) {
                case 1: input = input1; break;
                case 2: input = input2; break;
                case 3: input = input3; break;
            }
            return input[pointer++];
        }
    };

Answer 1

您不能同时拥有同一个MockUp子类的多个实例(每个这样的模拟都只是在实例化前一个子类时覆盖它)。相反，向Invocation方法中添加一个@Mock参数，然后使用它提供的信息来区分多个数据集。例如：

@Test
public void testClientWithVariedDataFromFastScanners()
{
    new MockUp<FastScanner>() {
        // some data structure for test data

        @Mock
        int nextInt(Invocation inv) {
            int idx = inv.getInvocationIndex();
            FastScanner fs = inv.getInvokedInstance();

            // Find the next value by using idx or fs as a lookup index
            // into the data structures:
            int i = ...

            return i;
        }
    };

    client.doSomethingUsingFastScanners();
}

另外，如果您想在一个模拟子类上调用任何方法(包括static方法)，只需将它变成一个命名类，而不是一个匿名类。

Answer 2

也许它比@Rogerio的解决方案更糟糕，但是我们可以使用带有静态字段的外部类。我是说：

    new MockUp<PrisonTransfer.FastScanner>() {

        private int[] input1 = new int[] {17, 2, 3, 1, 1, 1, 1, 1, 1, 3, 1, 1, 1, 1, 1, 1, 1, 3, 1, 1};
        private int[] input2 = new int[] {5, 2, 2, 3, 3, 3, 3, 3};
        private int[] input3 = new int[] {8, 2, 5, 1, 3, 1, 1, 1, 1, 3, 1};
        private int[] input4 = new int[] {4, 3, 3, 2, 3, 1, 1};
        private int[] input5 = new int[] {1, 1, 1, 2};
        private int[] input6 = new int[] {11, 4, 2, 2, 2, 0, 7, 3, 2, 2, 4, 9, 1, 4};

        @SuppressWarnings("unused")
        @Mock
        int nextInt() throws IOException {
            int[] input = null;
            switch (InputCounter.inputNumber) { //THE WHOLE POINT HERE!
                case 1: input = input1; break;
                case 2: input = input2; break;
                case 3: input = input3; break;
                case 4: input = input4; break;
                case 5: input = input5; break;
                case 6: input = input6; break;
            }
            return input[InputCounter.pointer++];
        }
    };

    private static class InputCounter {
        public static byte inputNumber = 1;
        public static byte pointer = 0;

        public void switchInput(int number) {
            this.inputNumber = i;
            this.pointer = 0;
        }
    }