java - 如何在 JUnit 测试中测试两个数组是否相等

Question

我有一个名为 MySet 的类，该类对数组执行各种操作，解释一下，它对数组与其他数组进行加、减、乘和除。我想测试一下数组添加方法，看看它是否正确运行。

这是 MySet 类:

封装实验室；

import java.util.Arrays;

public class MySet implements MyMath<MySet> {
int count = 0;
int[] firstArray = new int[count];

public MySet(int[] x) {

    int count = 0;
    Arrays.sort(x);
    for (int index = 0; index < x.length - 1; index++) {
        if (x[index] != x[index + 1]) {
            count++;
        }
    }

    firstArray = addToArray(x, count + 1);
  }
    public int[] addToArray(int[] x, int y) {
    int counter = 0;
    int[] changedArray = new int[y];
    for (int index = 0; index < x.length - 1; index++) {
        if (x[index] != x[index + 1]) {
            changedArray[counter] = x[index];
            counter++;
        }

    }
    changedArray[changedArray.length - 1] = x[x.length - 1];
    return changedArray;
  }

   public Boolean equals(MySet a) {
    if (a.firstArray.length != firstArray.length) {
        return false;
    }

    int test1 = firstArray.length - 1;
    int testValue = 0;
    for (int index = 0; index < a.firstArray.length; index++) {
        if (firstArray[index] == a.firstArray[index]) {
            testValue++;
        }
    }
    if (test1 == testValue) {
        return true;
    } else {
        return false;
    }
  }

  @Override
  public MySet add(MySet o) {
    int[] addedSet = new int[firstArray.length + o.firstArray.length ];
    for (int index = 0; index < firstArray.length; index++) {
        addedSet[index] = firstArray[index];
    }
    int counter = 0;
    for (int index = firstArray.length; index <= firstArray.length - 1 + 
    o.firstArray.length; index++) {
        addedSet[index] = o.firstArray[counter];
        counter++;
    }
    Arrays.sort(addedSet);
    addedSet = addToArray(addedSet, addedSet.length - 1);
    MySet finalSetAdd = new MySet(addedSet);
    return finalSetAdd;
    }

    @Override
    public MySet subtract(MySet o) {
    Arrays.sort(firstArray);
    Arrays.sort(o.firstArray);
    int count = 0;
    int finalCount = 0;
    int[] tester = addToArray(firstArray, firstArray.length - 1);
    int[] testing = addToArray(o.firstArray, o.firstArray.length - 1);

    for (int index = 0; index < testing.length; index++) {
        for (int counter = 0; counter < tester.length; counter++) {
            if (tester[index] != testing[counter]) {
                count++;
            }
        }
        if (count == tester.length) {
            finalCount++;
        }
        count = 0;
    }
    int size = 0;
    int[] finalOne = new int[finalCount];
    for (int index = 0; index < o.firstArray.length; index++) {
        for (int counter = 0; counter < firstArray.length; counter++) {
            if (testing[index] != tester[counter]) {
                finalOne[size] = testing[index];
                size++;
                finalOne = addToArray(finalOne, finalOne.length - 1);
            }
        }
    }
    MySet finalSetSub = new MySet(finalOne);
    return finalSetSub;

}

    @Override
    public MySet divide(MySet o) {
    Arrays.sort(firstArray);
    Arrays.sort(o.firstArray);
    int count = 0;
    int finalCount = 0;
    int[] tester = addToArray(firstArray, firstArray.length - 1);
    int[] testing = addToArray(o.firstArray, o.firstArray.length - 1);

    for (int index = 0; index < o.firstArray.length; index++) {
        for (int counter = 0; counter < firstArray.length; counter++) {
            if (testing[index] == tester[counter]) {
                count++;
            }
        }
        if (count == tester.length) {
            finalCount++;
        }
        count = 0;
    }
    int size = 0;
    int[] finalOne = new int[finalCount];
    for (int index = 0; index < o.firstArray.length; index++) {
        for (int counter = 0; counter < firstArray.length; counter++) {
            if (testing[index] == tester[counter]) {
                finalOne[size] = testing[index];
                size++;
                finalOne = addToArray(finalOne, finalOne.length - 1);

            }
        }
    }
    MySet finalSetSub = new MySet(finalOne);
    return finalSetSub;
    }

    @Override
    public MySet multiply(MySet o) {
    Arrays.sort(firstArray);
    Arrays.sort(o.firstArray);
    int count = 0;
    int finalCount = 0;
    int[] tester = addToArray(firstArray, firstArray.length - 1);
    int[] testing = addToArray(o.firstArray, o.firstArray.length - 1);

    for (int index = 0; index < o.firstArray.length; index++) {
        for (int counter = 0; counter < firstArray.length; counter++) {
            if (testing[index] != tester[counter]) {
                count++;
            }
        }
        if (count == firstArray.length - 1) {
            finalCount++;
        }
        count = 0;
    }
    int counter1 = 0;
    int size = 0;
    int[] finalOne = new int[finalCount];
    for (int index = 0; index < o.firstArray.length; index++) {
        for (int counter = 0; counter < firstArray.length; counter++) {
            if (testing[index] != tester[counter]) {
                counter1++;
            }
        }
        if (counter1 == firstArray.length - 1) {
            finalOne[size] = o.firstArray[index];
            size++;
        }

    }
    MySet finalSetSub = new MySet(finalOne);
    return finalSetSub;
    }

   public String toString(int x) {
    return "Value: " + firstArray[x];
   }

   }

这是我对 add 方法的测试:

package test;

import static org.junit.jupiter.api.Assertions.*;

import org.junit.jupiter.api.Test;

import lab.MyMath;
import lab.MySet;

class MySetTest {
@Test
public void testMysetAdd() {
    int[] set1Arr = {1,2,6};
    MyMath<MySet> set1 = new MySet(set1Arr);
    int[] set2Arr = {4,5,6};
    MyMath<MySet> set2 = new MySet(set2Arr);
    int[] s = {1,2,4,5,6};
    MyMath<MySet> sum = new MySet(s);
    assertEquals(set1.add((MySet)set2).equals(sum), sum.equals(sum));
    }
}

运行测试后，测试失败，显示“预期 但为: ”，因此 MySet 类中的 add 方法中存在错误，其中两个数组可能不是等于它们的实际总和，MySet 类中的 equals 方法，该方法不能正确检查两个数组是否相等，或者在测试本身中(我认为问题出在测试中)。我只是想知道我做错了什么以及如何解决它？

Answer 1

您实际上并没有检查数组，而是检查自定义对象MySet。不幸的是，您没有正确实现 equals()/hashCode()/toString() 。

1. 修复您的 MySet.equals 签名。它必须重写 Object 方法 boolean equals(Object) 而不是 Boolean equals(MySet a)。您可以应用@Override注释来确保此方法被正确覆盖。如果没有这个，大多数 JUnit 方法都会失败。

2. 添加相应的int hashCode()方法。

3. 添加一个将由断言消息使用的String toString()。

4. 更改assertEquals(set1.add((MySet)set2).equals(sum), sum.equals(sum));应写为:assertEquals(sum, set1.add((MySet)set2));。

5. 您可以尝试使用 assertArrayEquals() 而不是 assertEquals() 来改进断言消息。您还可以尝试更现代的断言库，例如AssertJ .