使用cobertura来测量单元测试的代码覆盖情况

Cobertura是一个基于jcoverage的免费Java工具，它能够显示哪一部分代码被你的测试所覆盖,并可生成HTML或XML报告． 本文将介绍如何在项目中使用cobertura来测量单元测试的代码覆盖情况.

首先创建一个Java项目，本文以Eclipse为例:

项目名: CodeCoverageTest

结构图如下:



接下，创建一个Ant构建配置文件，帮我们实现自动化的编译，单元测试以及cobertura来测量单元测试的代码覆盖情况。

Ant的 build.xml文件内容如下：

 1 <?xml version="1.0" encoding="UTF-8"?>
  2 
  3 <project name="cobertura.examples.basic" default="coverage" basedir=".">
  4     
  5     <!-- 引用 build.properties文件 配置路径信息-->
  6     <property file="build.properties" />
  7 
  8     <!-- 设置 cobertura路径 -->
  9     <path id="cobertura.classpath">
 10         <fileset dir="${cobertura.dir}">
 11             <include name="cobertura.jar" />
 12             <include name="lib/**/*.jar" />
 13         </fileset>
 14     </path>
 15 
 16     <!-- 配置 cobatura ant 扩展任务 -->
 17     <taskdef classpathref="cobertura.classpath" resource="tasks.properties"/>
 18 
 19     <target name="init">
 20         <mkdir dir="${classes.dir}" />
 21         <mkdir dir="${instrumented.dir}" />
 22         <mkdir dir="${reports.xml.dir}" />
 23         <mkdir dir="${reports.html.dir}" />
 24         <mkdir dir="${coverage.xml.dir}" />
 25         <mkdir dir="${coverage.html.dir}" />
 26     </target>
 27 
 28     <!-- 编译源代码 -->
 29     <target name="compile" depends="init">
 30         <javac srcdir="${src.dir}:${test.dir}:${src.conf.dir}:${test.conf.dir}" destdir="${classes.dir}" debug="yes">
 31             <classpath refid="cobertura.classpath" />
 32         </javac>
 33     </target>
 34 
 35     <target name="instrument" depends="init,compile">
 36         <!--
 37             Remove the coverage data file and any old instrumentation.
 38         -->
 39         <delete file="cobertura.ser"/>
 40         <delete dir="${instrumented.dir}" />
 41 
 42         <!--
 43             Instrument the application classes, writing the
 44             instrumented classes into ${build.instrumented.dir}.
 45         -->
 46         <cobertura-instrument todir="${instrumented.dir}">
 47             <!--
 48                 The following line causes instrument to ignore any
 49                 source line containing a reference to log4j, for the
 50                 purposes of coverage reporting.
 51             -->
 52             <ignore regex="org.apache.log4j.*" />
 53 
 54             <fileset dir="${classes.dir}">
 55                 <!--
 56                     Instrument all the application classes, but
 57                     don't instrument the test classes.
 58                 -->
 59                 <include name="**/*.class" />
 60                 <exclude name="**/*Test.class" />
 61             </fileset>
 62         </cobertura-instrument>
 63     </target>
 64 
 65     <!-- 单元测试 -->
 66     <target name="test" depends="init,compile">
 67         <junit fork="yes" dir="${basedir}" failureProperty="test.failed">
 68             <!--
 69                 Note the classpath order: instrumented classes are before the
 70                 original (uninstrumented) classes.  This is important.
 71             -->
 72             <classpath location="${instrumented.dir}" />
 73             <classpath location="${classes.dir}" />
 74 
 75             <!--
 76                 The instrumented classes reference classes used by the
 77                 Cobertura runtime, so Cobertura and its dependencies
 78                 must be on your classpath.
 79             -->
 80             <classpath refid="cobertura.classpath" />
 81 
 82             <formatter type="xml" />
 83             <test name="${testcase}" todir="${reports.xml.dir}" if="testcase" />
 84             <batchtest todir="${reports.xml.dir}" unless="testcase">
 85                 <fileset dir="${test.dir}">
 86                     <include name="**/*Test.java" />
 87                 </fileset>
 88                 <fileset dir="${src.dir}">
 89                     <include name="**/*Test.java" />
 90                 </fileset>                
 91             </batchtest>
 92         </junit>
 93 
 94         <junitreport todir="${reports.xml.dir}">
 95             <fileset dir="${reports.xml.dir}">
 96                 <include name="TEST-*.xml" />
 97             </fileset>
 98             <report format="frames" todir="${reports.html.dir}" />
 99         </junitreport>
100     </target>
101 
102     <target name="coverage-check">
103         <cobertura-check branchrate="34" totallinerate="100" />
104     </target>
105 
106     <!-- 生成 coverage xml格式报告 -->
107     <target name="coverage-report">
108         <!--
109             Generate an XML file containing the coverage data using
110             the "srcdir" attribute.
111         -->
112         <cobertura-report srcdir="${src.dir}" destdir="${coverage.xml.dir}" format="xml" />
113     </target>
114 
115     <!-- 生成 coverage html格式报告 -->
116     <target name="alternate-coverage-report">
117         <!--
118             Generate a series of HTML files containing the coverage
119             data in a user-readable form using nested source filesets.
120         -->
121         <cobertura-report destdir="${coverage.html.dir}">
122             <fileset dir="${src.dir}">
123                 <include name="**/*.java"/>
124             </fileset>
125         </cobertura-report>
126     </target>
127 
128     <target name="clean" description="Remove all files created by the build/test process.">
129         <delete dir="${classes.dir}" />
130         <delete dir="${instrumented.dir}" />
131         <delete dir="${reports.dir}" />
132         <delete file="cobertura.log" />
133         <delete file="cobertura.ser" />
134     </target>
135 
136     <target name="coverage" depends="compile,instrument,test,coverage-report,alternate-coverage-report" description="Compile, instrument ourself, run the tests and generate JUnit and coverage reports."/>
137 
138 </project>
139 

build.properties文件

 1 # The source code for the examples can be found in this directory
 2 src.dir=../src/java
 3 src.conf.dir=../src/conf
 4 test.dir=../test/java
 5 test.conf.dir=../src/conf
 6 
 7 # The path to cobertura.jar
 8 cobertura.dir=cobertura
 9 
10 # Classes generated by the javac compiler are deposited in this directory
11 classes.dir=../bin
12 
13 # Instrumented classes are deposited into this directory
14 instrumented.dir=instrumented
15 
16 # All reports go into this directory
17 reports.dir=reports
18 
19 # Unit test reports from JUnit are deposited into this directory
20 reports.xml.dir=${reports.dir}/junit-xml
21 reports.html.dir=${reports.dir}/junit-html
22 
23 # Coverage reports are deposited into these directories
24 coverage.xml.dir=${reports.dir}/cobertura-xml
25 coverage.html.dir=${reports.dir}/cobertura-html
26 

编写示例代码
Hello.java

 1 package com.xmatthew.practise.cobertura;
 2 
 3 public class Hello {
 4 
 5     public String birthday(String name) {
 6         return "happy birthday to " + name;
 7     }
 8    
 9     public String christmas(String name) {
10         return "merry christmas " + name;
11     }
12     
13 }

编写测试Hello.java的测试类，进行单元测试
HelloTest.java

 1 package com.xmatthew.practise.cobertura;
 2 
 3 import junit.framework.Assert;
 4 import junit.framework.TestCase;
 5 
 6 public class HelloTest extends TestCase {
 7     
 8     private Hello hello;
 9 
10     protected void setUp() throws Exception {
11         hello = new Hello();
12     }
13 
14     protected void tearDown() throws Exception {
15         hello = null;
16     }
17 
18     public void testBirthday() {
19         String expected = "happy birthday to matt";
20         Assert.assertEquals(expected, hello.birthday("matt"));
21     }
22 
23     public void testChristmas() {
24         String expected = "merry christmas matt";
25         Assert.assertEquals(expected, hello.christmas("matt"));
26     }
27 
28 }
29 

接下来，我们运行 Cobertura来进行测试
运行 Cobertura,测试在Eclipse运行时，要在Ant插件的运行类库环境中加入cobertura相关类库。



查看运行结果报告:

JUnit报告

Cobertura报告






到目前已经完成整个项目的基于Ant进行编译，测试以及生成Cobertura测试报告的开发IDE环境。这个项目框架足以应用日常的开发需求。

Cobertura官网地址: http://cobertura.sourceforge.net/