Question

对用户定义的对象进行序列化Junit测试后，它失败了，并给了我结果

预期：com.me.Position@7a92922

实际：com.me.Position@25618e91

我定义了以下课程

public class Position {

    private double x;
    private double y;

    /**
     * default constructor
     */
    public Position() {
    }

    /**
     * paramterized constructor
     * 
     * @param x
     *          x-coordinate
     * @param y
     *          y-coordinate
     */
    public Position(double x, double y) {
        this.x = x;
        this.y = y;
    }

    public double getX() {
        return x;
    }

    public void setX(double x) {
        this.x = x;
    }

    public double getY() {
        return y;
    }

    public void setY(double y) {
        this.y = y;
    }
}

然后，我定义了另一个类来序列化和反序列化Position对象，该对象是上一类的实例，如下所示

public class PositionSerializer {

    static void serialize(Position position, OutputStream outputStream) {
        OutputStreamUtil.serializeDouble(position.getX(), outputStream);
        OutputStreamUtil.serializeDouble(position.getY(), outputStream);
    }

    static Position deserialize(InputStream inputStream) {
        double x = InputStreamUtil.deserializeDouble(inputStream);
        double y = InputStreamUtil.deserializeDouble(inputStream);
        Position positionObject = new Position();
        positionObject.setX(x);
        positionObject.setY(y);
        return positionObject;
    }
}

最后，我编写了如下的单元测试

public class PositionSerializerTest {

    private InputStream iStream;
    private ByteArrayOutputStream oStream;

    @Before
    public void init() {
        oStream = new ByteArrayOutputStream();
    }

    Position serialzeAndDeserializeObject(Position positionObject) {
        PositionSerializer.serialize(positionObject, oStream);
        iStream = new ByteArrayInputStream(oStream.toByteArray());
        return PositionSerializer.deserialize(iStream);
    }

    @Test
    public void equals_equal() {
        Position positionObject = new Position(5.5, 10.5);
        Position deserializedPosition = serialzeAndDeserializeObject(positionObject);
        assertThat(deserializedPosition).isEqualTo(positionObject);
    }
}

怎么了？以及如何解决？

Answer 1

没有错，但是您正在使用反序列化方法创建新实例：

Position positionObject = new Position();

这将始终调用Position Object的新实例，因此您无法使用==运算符进行比较

您应该重写equals方法，如下所示：

public boolean equals(Object o) {
    if (o == this) {
        return true;
    }
    if (!(o instanceof Position)) {
        return false;
    }
    Position otherObject = (Position)o;
    if(this.x == otherObject.x && this.y == otherObject.y)
        return true;
    else return false;
}

然后致电：

assertThat(deserializedPosition).isEqualTo(positionObject);

Answer 2

您正在检查不相等的引用相等性，因为您的反序列化方法在每次调用时都会返回新实例，请在下面使用它们比较值：

assertThat(deserializedPosition.getX()).isEqualTo(positionObject.getX())    
assertThat(deserializedPosition.getY()).isEqualTo(positionObject.getY())

Answer 3

看起来您的测试正在比较对象引用而不是对象值。覆盖equals函数或分别比较position对象中的每个值。

用户定义对象序列化的Junit测试失败

3 个答案: