把我剛測試成功的例子（3分鐘前）記錄下來放在這里，希望會對剛開始研究Junit的朋友有點幫助。

到jakarta當一份apache-ant安裝到你的系統上，并把ant/bin加到系統變量path中，使你的ant命令可以在任何地方被調用。
當一份junit3.8.1安裝到你的系統上（解壓縮，把junit.jar加到系統變量classpath中）。

建立測試目錄JunitTest
把java文件,統一放到JunitTest/src目錄,根據package建與之相關的目錄.
文件1:

HelloWorld.java

package com.company;

public class HelloWorld {
public String sayHello() {
return "Hello World!";
}

public static void main( String[] args ) {
HelloWorld world = new HelloWorld();
System.out.println(world.sayHello());
}
}



文件2:

AllJunitTests.java

package test.com.company;

import junit.framework.Test;
import junit.framework.TestCase;
import junit.framework.TestSuite;

public class AllJunitTests extends TestCase{
public AllJunitTests(String name){
super(name);
}

public static Test suite(){
TestSuite suite = new TestSuite();
//TestSuite suite = new TestSuite();
suite.addTestSuite(HelloWorldTest.class);

return suite;
}
}


文件3:


HelloWorldTest.java

package test.com.company;

import com.company.HelloWorld;
import junit.framework.TestCase;
import junit.framework.AssertionFailedError;
import junit.framework.Assert;


/**
* JUnit 3.8.1 testcases for HelloWorld
*/
public class HelloWorldTest extends TestCase {

public HelloWorldTest(String name) {
super(name);
}

public static void main(String args[]) {
junit.textui.TestRunner.run(HelloWorldTest.class);
}

public void testSayHello() {
HelloWorld world = new com.company.HelloWorld();
assertEquals("Hello World!", world.sayHello() );
}
}



我的build.xml放到JunitTestuild,構造這個文件才可以使用ant命令來執行,包括編譯、打包、測試junit用例

<?xml version="1.0" encoding="UTF-8" ?>

<project name="anita" default="main" basedir="../">
<property name="app.name" value="sayhello" />
<property name="build.dir" value="build/classes" />

<target name="JUNIT">
<available property="junit.present" classname="junit.framework.TestCase" />
</target>

<target name="compile" depends="JUNIT">
<mkdir dir="${build.dir}"/>
<javac srcdir="src/" destdir="${build.dir}" >
<include name="**/*.java"/>
</javac>
</target>

<target name="jar" depends="compile">
<mkdir dir="build/lib"/>
<jar jarfile="build/lib/${app.name}.jar"
basedir="${build.dir}" includes="com/**"/>
</target>

<target name="compiletests" depends="jar">
<mkdir dir="build/testcases"/>
<javac srcdir="src/test" destdir="build/testcases">
<classpath>
<pathelement location="build/lib/${app.name}.jar" />
<pathelement path="" />
</classpath>
<include name="**/*.java"/>
</javac>
</target>

<target name="runtests" depends="compiletests" if="junit.present">
<java fork="yes" classname="junit.textui.TestRunner"
taskname="junit" failonerror="true">
<arg value="test.com.company.AllJunitTests"/>
<classpath>
<pathelement location="build/lib/${app.name}.jar" />
<pathelement location="build/testcases" />
<pathelement path="" />
<pathelement path="${java.class.path}" />
</classpath>
</java>
</target>
</project>



如果是win系統，在DOS窗口下進入你的工作目錄，并到 ../JunitTest/build下，執行ant runtests命令，會看到如下信息

D:TEMPJunitTestTestCaseuild>ant runtests
Buildfile: build.xml

JUNIT:

compile:
[mkdir] Created dir: D:TEMPJunitTestTestCaseuildclasses
[javac] Compiling 3 source files to D:TEMPJunitTestTestCaseuildclasses


jar:
[mkdir] Created dir: D:TEMPJunitTestTestCaseuildlib
[jar] Building jar: D:TEMPJunitTestTestCaseuildlibsayhello.jar

compiletests:
[mkdir] Created dir: D:TEMPJunitTestTestCaseuild estcases
[javac] Compiling 2 source files to D:TEMPJunitTestTestCaseuild estcas
es

runtests:
[junit] .
[junit] Time: 0

[junit] OK (1 test)

BUILD SUCCESSFUL
Total time: 7 seconds


<中間休息^_^>


下面請把 com/company/HelloWorld.java文件中的return "Hello World!";改成return "Hello world!!"，并在../JunitTest/builde目錄運行下運行ant runtests。
我們會看到如下情形：
……………………………………
……………………………………
runtests:
[junit] .F
[junit] Time: 0.01
[junit] There was 1 failure:
[junit] 1) testSayHello(test.com.company.HelloWorldTest)junit.framework.Comp
arisonFailure: expected:<...World...> but was:<...world!...>
[junit] at test.com.company.HelloWorldTest.testSayHello(Unknown Source)
[junit] at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
[junit] at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAcces
sorImpl.java:39)
[junit] at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMet
hodAccessorImpl.java:25)

[junit] FAILURES!!!
[junit] Tests run: 1, Failures: 1, Errors: 0
BUILD FAILED


我們可以看到，這是JUNIT測試用例未正常運行通過的錯誤信息。