如何更改 Mockito 中字符串的默认返回值?

问题描述

这个 2010 年的问题暗示了我正在尝试做的事情.

我正在做一个单元测试，它练习需要许多模拟对象来完成它需要做的事情的代码(测试 HTML + PDF 渲染).为了使这个测试成功，我需要生成许多模拟对象，并且这些对象中的每一个最终都会将一些字符串数据返回给正在测试的代码.

I'm working on a unit test which exercises code that requires many mocked objects to do what it needs to do (testing HTML + PDF rendering). For this test to be successful I need many mocked objects to be generated and each of these objects ultimately return some String data to the code being tested.

我认为我可以通过实现我自己的 Answer 类或 IMockitoConfiguration 来做到这一点，但我不确定如何实现这些它们只影响返回字符串的方法.

I think I can do this by implementing either my own Answer class or IMockitoConfiguration, but I am not sure how to implement those so they only affect methods which return Strings.

感觉下面的代码和我想要的很接近.它抛出一个强制转换异常，java.lang.ClassCastException: java.lang.String cannot be cast to com.mypackage.ISOCountry.我认为这意味着我需要以某种方式默认或限制 Answer 只影响 String 的默认值.

I feel that the following code is close to what I want. It throws a cast exception, java.lang.ClassCastException: java.lang.String cannot be cast to com.mypackage.ISOCountry. I think this means I need to somehow default or limit the Answer to only affect the defaults for String.

private Address createAddress(){
    Address address = mock(Address.class, new StringAnswer() );

    /* I want to replace repetitive calls like this, with a default string. 
    I just need these getters to return a String, not a specific string.

    when(address.getLocality()).thenReturn("Louisville");
    when(address.getStreet1()).thenReturn("1234 Fake Street Ln.");
    when(address.getStreet2()).thenReturn("Suite 1337");
    when(address.getRegion()).thenReturn("AK");
    when(address.getPostal()).thenReturn("45069");   
    */

    ISOCountry isoCountry = mock(ISOCountry.class);
    when(isoCountry.getIsocode()).thenReturn("US");
    when(address.getCountry()).thenReturn(isoCountry);

    return address;
}

//EDIT: This method returns an arbitrary string
private class StringAnswer implements Answer<Object> {
    @Override
    public Object answer(InvocationOnMock invocation) throws Throwable {
        String generatedString = "Generated String!";
           if( invocation.getMethod().getReturnType().isInstance( generatedString )){
               return generatedString;
           }
           else{
               return Mockito.RETURNS_DEFAULTS.answer(invocation);
           }
       }
}

如何设置 Mockito 以默认为返回 String 的模拟类上的方法返回生成的 String?我在 SO 上找到了这部分问题的解决方案

How can I set up Mockito to return a generated String by default for methods on a mocked class which return String? I found a solution to this part of the question on SO

另外，我怎样才能使生成的值成为 Class.methodName 形式的字符串?例如 "Address.getStreet1()" 而不仅仅是一个随机字符串?

For extra points, how can I make that generated value be a String which is in the form Class.methodName? For example "Address.getStreet1()" instead of just a random String?

推荐答案

我能够完全回答我自己的问题.

I was able to completely answer my own question.

在此示例中，生成的地址为路易斯维尔地区，而其他字段类似于address.getStreet1();".

In this example an address with the Locality of Louisville is generated while the other fields look like "address.getStreet1();".

private Address createAddress(){
    Address address = mock(Address.class, new StringAnswer() );

    when(address.getLocality()).thenReturn("Louisville");

    ISOCountry isoCountry = mock(ISOCountry.class);
    when(isoCountry.getIsocode()).thenReturn("US");
    when(address.getCountry()).thenReturn(isoCountry);

    return address;
}

private class StringAnswer implements Answer<Object> {
    @Override
    public Object answer(InvocationOnMock invocation) throws Throwable {
           if( invocation.getMethod().getReturnType().equals(String.class)){
               return invocation.toString();
           }
           else{
               return Mockito.RETURNS_DEFAULTS.answer(invocation);
           }
       }
}

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