尝试编写 Junit 测试，但失败了

Question

这是我的代码：

Concatenate.java

package concatenate;

import java.util.Scanner;

public class Concatenate {
    private static String firstWord;
    private static String secondWord;

    public Concatenate(String firstWord, String secondWord) {
        Concatenate.firstWord = firstWord;
        Concatenate.secondWord = secondWord;
    }

    public String getFirst() {
        return firstWord;
    }

    public String getSecond() {
        return secondWord;
    }

    public static Concatenate something() {
        Scanner myObj = new Scanner(System.in);
        System.out.println("Enter first word");
        firstWord = myObj.nextLine();
//        Scanner newObj = new Scanner(System.in);
        System.out.println("Enter second word");
        secondWord = myObj.nextLine();
        return new Concatenate(firstWord, secondWord);
    }

    public static void main(String[] args) {
        Concatenate result = something();
        System.out.println(result.getFirst() + " " + result.getSecond());
    }

}

ConcatenateTest.java

package concatenate;

import org.junit.Test;
import static org.junit.Assert.*;

public class ConcatenateTest {

    public ConcatenateTest() {
    }

    @Test
    public void testMain() {
        String firstWord = "Hello";
        String secondWord = "world";
        String expectedResult = "Hello world";
        Concatenate testResult = new Concatenate(firstWord, secondWord);
        assertEquals(expectedResult, testResult);
        assertEquals(1, 1);
    }
}

但是当我运行测试时，它失败了，我得到...

Expected <hello world> but was concatenate.Concatenate@[alphanumeric string]

有什么指点吗？

顺便说一句，我试图将所有这些复制到 Eclipse，但它引发了一大堆额外的错误。如果有人能告诉我为什么那也很好。 https://i.imgur.com/iES6owx.jpg

TIA

Answer 1

测试失败，因为 expectedResult 是一个字符串，而 testResult 是一个 Concatenate 的实例。他们不相等。

"Hello world".equals(testResult) == false

Answer 2

因为您正在比较 String 和 Concatenate 对象。所以它不会匹配。

最好在 Concatenate class 中创建一个 concat 方法并对方法的输出断言

public String concat() {
    return firstWord + " " + secondWord;}

并比较

assertEquals(expectedResult, testResult.concat());

希望这能澄清您的问题

Answer 3

"I understand that, thanks, but what's the solution then please? Because when I try to make my Concatenate function return a String I get the error missing return statement"

你在谈论你的构造函数吗？如果是它不能有 return。您可以覆盖 equals 方法然后更改您的测试

@Override
public String toString() {
    
    return firstWord +" "+secondWord;
}


assertEquals(expectedResult, testResult.toString());

尝试编写 Junit 测试，但失败了

Trying to write a Junit test, but it's failing

java

junit

junit4