测试驱动开发(TDD)实战体验-蒲公英云

测试驱动开发(TDD)实战体验

Dear 丶 2023-10-10 09:36 100阅读 0赞

在上一篇文章中写了关于TDD的理论，感兴趣的小伙伴可以去阅读一下。今天这篇文章以一个简单的例子来体验一下TDD的过程。

环境

Java 8
Junit 5

需求

我们有这样子的一个需求：客户需要一个长方形，能够给长方形设置宽和高，并且能够计算面积

1.编写测试用例

此时的Rectangle类如下

class Rectangle {

private double width;
private double height;
public void setWidth(double width) {
    this.width = width;
}
public void setHeight(double height) {
    this.height = height;
}

}

编写测试case

public class RectangleTest {

@Test
void should_return_20_when_width_2_and_height_10() {
    double width = 2;
    double height = 10;
    Rectangle rectangle = new Rectangle();
    rectangle.setWidth(width);
    rectangle.setHeight(height);
    assert (rectangle.count(width, height) == 20);
}

}

2.运行测试用例

就会看到测试case运行失败了（因为你还没写功能代码）

3.编写业务代码

class Rectangle {
    private double width;
    private double height;
    public void setWidth(double width) {
        this.width = width;
    }
    public void setHeight(double height) {
        this.height = height;
    }
    public double count(double width, double height) {
         return width * height;
    }
}

4.运行测试用例，然后看到测试用例通过了

5.对代码查缺补漏，进行重构

补充测试用例

public class RectangleTest {

@Test
void should_return_20_when_width_2_and_height_10() {
    double width = 2;
    double height = 10;
    Rectangle rectangle = new Rectangle();
    rectangle.setWidth(width);
    rectangle.setHeight(height);
    assert (rectangle.count(width, height) == 20);
}
@Test
void should_throw_exception_when_width_given_error_value() {
    double width = -10;
    double height = 10;
    Rectangle rectangle = new Rectangle();
    assertThrows(IllegalArgumentException.class, () -> rectangle.count(width, height));
}

}

运行测试用例，发现失败了

然后补充代码，此时的Rectangle类如下

class Rectangle {

private double width;
private double height;
public void setWidth(double width) {
    this.width = width;
}
public void setHeight(double height) {
    this.height = height;
}
public double count(double width, double height) {
    if (width <= 0 || height <= 0) {
        throw new IllegalArgumentException();
    }
    return width * height;
}