接到了个任务，需要对数字进行计算，因为涉及到整数，小数，和科学计数法等很多条件，所以人工测试非常麻烦，于是想到了PHP的单元测试工具PHPUnit，所以写个文档备查。

看了PHPUnit的文档之后基本有了一些了解，
http://pear.php.net/manual/en/packages.php.phpunit.intro.php

工作流程如下：
1.设计你的class/API
2.创建测试程序集
3.实现class/API
4.运行测试
5.修正测试失败或错误，回到第4步。

我们来举个例子：
下面是你要测试的class，其中formatn函数一个取任意数字的5位有效数字的函数。

CODE:
----------format_number.php-----------
class fo {

        function fo() {
        }

        function formatn($num) {
                $num = rtrim($num，"0");
                $pos = strpos($num，".");
                $num = str_replace("."，""，$num);
                $count1 = strlen($num);
                $num = ltrim($num，"0");
                $count2 = strlen($num);
                $zeroc = $count1 - $count2;
                $num = substr($num，0，6);
                $num = round($num/10);
                //$num = str_pad($num， 5， "0");
                if ($pos !== false) {
                        $num = str_pad($num， (strlen($num)+$zeroc)， "0"， STR_PAD_LEFT);
                        $dotl = substr($num，0，$pos);
                        $dotr = substr($num，$pos);
                        $num = $dotl.".".$dotr;
                }
                return $num;
        }

}
接着创建TestCase，继承自PHPUnit_TestCase

CODE:
----------testcase.php-----------

require_once 'format_number.php';
require_once 'PHPUnit.php';

class foTest extends PHPUnit_TestCase {

        //这个成员变量是存放要测试的类引用
        var $abc;

        //构造函数
        function foTest($name) {
                $this->;PHPUnit_TestCase($name);
        }

        //new一个要测试的类为成员变量abc赋值
        function setUp() {
                $this->;abc = new fo;
        }

        //unset要测试的类
        function tearDown() {
                unset($this->;abc);
        }

        //自定义的testcase
        function testFormatn1() {
                //调用要测试的类的方法，结果放到$result变量
                $result = $this->;abc->;formatn("100.234");
                //期望结果
                $expected = "100.23";
                //判断是否相等，这里使用assertTrue方法来判断布而值是否为true。
                $this->;assertTrue($result == $expected);
        }

        function testFormatn2() {
                $result = $this->;abc->;formatn("0.100234");
                $expected = "0.10023";
                $this->;assertTrue($result == $expected);
        }

        function testFormatn3() {
                $result = $this->;abc->;formatn("0.100235");
                $expected = "0.10024";
                $this->;assertTrue($result == $expected);
        }

        function testFormatn4() {
                $result = $this->;abc->;formatn("0.000100235");
                $expected = "0.00010024";
                $this->;assertTrue($result == $expected);
        }

        function testFormatn5() {
                $result = $this->;abc->;formatn("0.000100232");
                $expected = "0.00010023";
                $this->;assertTrue($result == $expected);
        }

        function testFormatn6() {
                $result = $this->;abc->;formatn("1343");
                $expected = "1343";
                $this->;assertTrue($result == $expected);
        }

        function testFormatn7() {
                $result = $this->;abc->;formatn("1343.01");
                $expected = "1343";
                $this->;assertTrue($result == $expected);
        }

        function testFormatn8() {
                $result = $this->;abc->;formatn("1343.05");
                $expected = "1343.1";
                $this->;assertTrue($result == $expected);
        }

        function testFormatn9() {
                $result = $this->;abc->;formatn("0");
                $expected = "0";
                $this->;assertTrue($result == $expected);
        }

        function testFormatn10() {
                $result = $this->;abc->;formatn("105.2342");
                $expected = "105.23";
                $this->;assertTrue($result == $expected);
        }

        function testFormatn11() {
                $result = $this->;abc->;formatn("105.2375");
                $expected = "105.24";
                $this->;assertTrue($result == $expected);
        }

        function testFormatn12() {
                $result = $this->;abc->;formatn("0.000523751");
                $expected = "0.00052375";
                $this->;assertTrue($result == $expected);
        }

        function testFormatn13() {
                $result = $this->;abc->;formatn("0.000523755");
                $expected = "0.00052376";
                $this->;assertTrue($result == $expected);
        }

}