問(wèn)題描述

我正在使用 Mockito 進(jìn)行后期單元測(cè)試.我對(duì)何時(shí)使用 doAnswer 和 thenReturn 感到困惑.

I am using Mockito for service later unit testing. I am confused when to use doAnswer vs thenReturn.

誰(shuí)能幫我詳細(xì)介紹一下?到目前為止，我已經(jīng)用 thenReturn 進(jìn)行了嘗試.

Can anyone help me in detail? So far, I have tried it with thenReturn.

推薦答案

當(dāng)你在 mock 一個(gè)方法時(shí)知道返回值時(shí)，你應(yīng)該使用 thenReturn 或 doReturn稱呼.調(diào)用模擬方法時(shí)會(huì)返回此定義的值.

You should use thenReturn or doReturn when you know the return value at the time you mock a method call. This defined value is returned when you invoke the mocked method.

thenReturn(T value) 設(shè)置調(diào)用方法時(shí)要返回的返回值.

thenReturn(T value) Sets a return value to be returned when the method is called.

@Test
public void test_return() throws Exception {
    Dummy dummy = mock(Dummy.class);
    int returnValue = 5;

    // choose your preferred way
    when(dummy.stringLength("dummy")).thenReturn(returnValue);
    doReturn(returnValue).when(dummy).stringLength("dummy");
}

Answer 用于在調(diào)用模擬方法時(shí)需要執(zhí)行其他操作，例如當(dāng)需要根據(jù)該方法調(diào)用的參數(shù)計(jì)算返回值時(shí).

Answer is used when you need to do additional actions when a mocked method is invoked, e.g. when you need to compute the return value based on the parameters of this method call.

當(dāng)您想使用通用 Answer 存根 void 方法時(shí)，請(qǐng)使用 doAnswer().

Use doAnswer() when you want to stub a void method with generic Answer.

Answer 指定了一個(gè)執(zhí)行的動(dòng)作和一個(gè)在你與 mock 交互時(shí)返回的返回值.

Answer specifies an action that is executed and a return value that is returned when you interact with the mock.

@Test
public void test_answer() throws Exception {
    Dummy dummy = mock(Dummy.class);
    Answer<Integer> answer = new Answer<Integer>() {
        public Integer answer(InvocationOnMock invocation) throws Throwable {
            String string = invocation.getArgumentAt(0, String.class);
            return string.length() * 2;
        }
    };

    // choose your preferred way
    when(dummy.stringLength("dummy")).thenAnswer(answer);
    doAnswer(answer).when(dummy).stringLength("dummy");
}

這篇關(guān)于Mockito:doAnswer Vs thenReturn的文章就介紹到這了，希望我們推薦的答案對(duì)大家有所幫助，也希望大家多多支持html5模板網(wǎng)！