TestForGit

package com.example.lenovo.textforgit;

/**
 * Created by Lenovo on 2017/3/13.
 */

public class Calculator {
    public double sum(double a, double b) {
        return a+b;
    }

    public double substract(double a, double b) {
        return a-b ;
    }

    public double divide(double a, double b) {
        return a/b;
    }

    public double multiply(double a, double b) {
        return a*b;
    }
}

测试代码：

package com.example.lenovo.textforgit;

import org.junit.Before;
import org.junit.Test;

import static org.junit.Assert.*;

/**
 * Created by Lenovo on 2017/3/13.
 */
public class CalculatorTest {
    private Calculator mcalculator;
    @Before
    public void setUp() throws Exception {
        mcalculator = new Calculator();

    }

    @Test
    public void sum() throws Exception {
     assertEquals(8d,mcalculator.sum(3d,5d),0);

    }

    @Test
    public void substract() throws Exception {
        assertEquals(1d,mcalculator.substract(5d,4d),0);

    }

    @Test
    public void divide() throws Exception {
        assertEquals(4d,mcalculator.divide(20d,5d),0);

    }

    @Test
    public void multiply() throws Exception {
        assertEquals(10d,mcalculator.multiply(2d,5d),0);

    }

}

下面是测试运行结果