Java之----如何进行单元测试来测试代码

我们可以看一个例子：
1)创建一个工程，叫SuiteUnitTesting，在这个工程中创建4个类，如下图所示：

代码清单如下：

public abstract class Shape
{
    public abstract double perimeter();//计算周长，抽象方法
    public abstract double area();//计算面积，抽象方法
}
public class Rectangle extends Shape
{
    int a;//边长
    int b;//边长
    public Rectangle(int x,int y)
    {
        a=x;
        b=y;
    }
    public double perimeter()
    {
        return 2*(a+b);
    }
    public double area()
    {
        return a*b;
    }
}
public class Circle extends Shape
{
    private int r;//半径
    public Circle(int x)
    {
        r=x;
    }
    public double perimeter()
    {
        return 2*3.14*r;
    }
    public double area()
    {
        return 3.14*r*r;
    }
}
public class Square extends Rectangle
{
    public Square(int x,int y)
    {
        super(x,y);
    }
    public double perimeter()
    {
        return 4*a;
    }
    public double area()
    {
        return a*a;
    }
}

2)针对我们要测试的Rectangle、Circle、Square3个类设计测试用例。
3)在SuiteUnitTesting工程下创建三个新类TestRectangle、TestCircle和TestSquare，分别实现我们在第二步设计的测试用例。

import junit.framework.TestCase;
import org.junit.Test;

public class TestRectangle extends TestCase {
    public TestRectangle(String arg){
        super(arg);
    }
    @Test
    public String isRectangle(int x,int y){
        if(x>0&&y>0){
            Rectangle rec = new Rectangle(x,y);
            return "是矩形,"+"perimeter = "+rec.perimeter()+" area = "+rec.area();
        }else{
            return "不是矩形";
        }
    }
    @Test
    public void testOne(){
        System.out.println(isRectangle(0,0));
    }
    @Test
    public void testTwo(){
        System.out.println(isRectangle(-1,2));
    }
    @Test
    public void testThree(){
        System.out.println(isRectangle(1,-2));
    }
    @Test
    public void testFour(){
        System.out.println(isRectangle(2,2));
    }
    public static  void main(String arg[]){

        junit.textui.TestRunner.run(TestRectangle.class);
    }
}

import junit.framework.TestCase;
import org.junit.Test;

public class TestCircle extends TestCase {
    public TestCircle(String arg){
        super(arg);
    }
        public String isCircle(int r){
            if(r>0){
                Circle circle = new Circle(r);
                return "是圆形,"+"perimeter = "+circle.perimeter()+", area = "+circle.area();
            }else{
                return "不是圆形";
            }
        }
        @Test
        public void testOne(){
            System.out.println(isCircle(-1));
        }
        @Test
        public void testTwo(){
            System.out.println(isCircle(0));
        }
        @Test
        public void testThree(){
            System.out.println(isCircle(2));
        }
    public static  void main(String arg[]){
        junit.textui.TestRunner.run(TestCircle.class);
    }
}

import junit.framework.TestCase;
import org.junit.Test;

public class TestSquare extends TestCase {
    public TestSquare(String arg){
        super(arg);
    }
    public String isSquare(int x,int y){
        if(x>0){
            Square square = new Square(x,y);
            return "是正方形,"+"perimeter = "+square.perimeter()+" area = "+square.area();
        }else{
            return "不是正方形";
        }
    }
    @Test
    public void testOne(){
        System.out.println(isSquare(0,0));
    }
    @Test
    public void testTwo(){
        System.out.println(isSquare(-1,2));
    }
    @Test
    public void testThree(){
        System.out.println(isSquare(1,-2));
    }
    @Test
    public void testFour(){
        System.out.println(isSquare(2,2));
    }
    public static  void main(String arg[]){

        junit.textui.TestRunner.run(TestSquare.class);
    }
}

4)建立一个Suite，组装自己的测试，我们在这里，组装TestRectangle和TestCircle，代码如下：

import junit.framework.*;
public class TestShape {
    public static Test suite() throws Exception
    {
        TestSuite suite =new  TestSuite("Some tests from part 1 ");
        suite.addTestSuite(TestRectangle.class);
        suite.addTestSuite(TestCircle.class);
        return suite;
    }
}

5)在开始—〉运行—〉cmd，在命令行提示符下，输入：

java  junit.swingui.TestRunner  TestShape

查看出现的结果运行窗，看一共执行了多少个测试，并记录测试的结果。