Question

我创建了一个带有自定义消息和错误代码的CustomException。

public class CustomException extends RuntimeException{
private int errorCode;

public CustomException(String message,int errorCode){
    super(message);
    this.errorCode=errorCode;
}

public int getErrorCode(){
    return this.errorCode;
}

public String getMessage(){
    return "Message: "+super.getMessage()+" ErrorCode: "+this.errorCode;
}
}

当我在列表中添加空值时抛出CustomException，并显示消息“Null”和错误代码1.当我添加一个空值时，异常消息为“Empty”，错误代码为2。如何在单元测试中捕获和测试错误代码？我做过类似的事情：

public class MyListTester { private Class exceptionType = CustomException.class;

 @Test
 public void testAddNonNullValue() {
      exception.expect(exceptionType);
      exception.expectMessage("Null");
      list.add(null);
}

但我没有访问错误代码

Answer 1

诀窍是使用expect规则的ExpectedException方法，该方法以Matcher为参数，并编写自定义匹配器以验证错误代码。这是一个完整的例子：

public class MyListTester {

    @Rule
    public ExpectedException exception = ExpectedException.none();

    @Test
    public void testAddNullValue() {
        MyList list = new MyList();
        exception.expect(CustomException.class);
        exception.expectMessage("Null");
        exception.expect(errorCode(1));
        list.add(null);
    }

    @Test
    public void testAddEmptyValue() {
        MyList list = new MyList();
        exception.expect(CustomException.class);
        exception.expectMessage("Empty");
        exception.expect(errorCode(2));
        list.add(emptyValue);
    }

    private Matcher<? extends CustomException> errorCode(final int errorCode) {
        return new CustomTypeSafeMatcher<CustomException>("errorCode " + errorCode) {
            @Override
            protected boolean matchesSafely(CustomException e) {
                return e.getErrorCode() == errorCode;
            }
        };
    }
}

带错误代码的自定义异常

1 个答案: