{"id":585,"date":"2014-02-25T01:53:48","date_gmt":"2014-02-25T01:53:48","guid":{"rendered":"http:\/\/choudhury.com\/blog\/?p=585"},"modified":"2018-12-20T01:06:33","modified_gmt":"2018-12-20T01:06:33","slug":"enforcing-minimum-code-coverage","status":"publish","type":"post","link":"https:\/\/choudhury.com\/blog\/2014\/02\/25\/enforcing-minimum-code-coverage\/","title":{"rendered":"Enforcing Minimum Code Coverage"},"content":{"rendered":"

If you want to enforce minimum code coverage check, JaCoCo <\/a>worked really in the projects that I’ve worked on so far.<\/p>\n

JaCoCo works as agent (there is another option where it can do offline instrumentation<\/a>). The prepare-agent goal sets up the “jacocoProperty” property to setup JaCoCo as agent on the the surefire argLine (so it will only work if sure-fire is configured to run your unit tests in forked process)<\/p>\n

Here is basic maven project<\/a> that demonstrates how to check minimum line and branch coverage of 80% is met.<\/p>\n

Prepare Agent Goal<\/strong><\/p>\n

<plugin>
\n        <groupId>org.jacoco<\/groupId>
\n        <artifactId>jacoco-maven-plugin<\/artifactId>
\n        <version>0.8.2<\/version>
\n       
\n         <executions>
\n
\n           <!--  (1)  Prepare agent runs in the init phase, it setups the jacocoProperty,  so we can insert this to the maven sure fire argLine and get to run jacoco as agent -->
\n          <execution>
\n            <id>prepare-agent<\/id>
\n            <goals>
\n              <goal>prepare-agent<\/goal>
\n            <\/goals>
\n            <configuration>
\n              <propertyName>jacocoArgLine<\/propertyName>
\n              <includes>
\n                <include>com.choudhury.codecoverage.*<\/include>
\n              <\/includes>
\n            <\/configuration>
\n          <\/execution><\/div><\/div>\n

SureFire Plugin Argline<\/strong><\/p>\n

We run sure fire and we add the “jacocoProperty” as part of the argLine<\/p>\n

 <plugin>
\n        <groupId>org.apache.maven.plugins<\/groupId>
\n        <artifactId>maven-surefire-plugin<\/artifactId>
\n        <version>2.22.1<\/version>
\n        <configuration>
\n            <!-- (2)  setup the argLine and run the unit tests.   **NOTE the "jacocArgeLine" property was configured the "prepare-agent" goal of Jacoco  (see below) -->
\n            <argLine>${jacocoArgLine} -Xmx256m<\/argLine>
\n        <\/configuration>
\n      <\/plugin><\/div><\/div>\n

After the forked sure fire process is has completed it write the jacoco.exec file in the target file. This file is required for both the “check” and “report” JaCoCo goals.<\/p>\n

\"jacoco_coverage_file\"<\/a><\/p>\n

Check Goal<\/strong>
\nIn verify phase, we execute the check <\/a>goal of JaCoCo<\/p>\n

          <!--  (3) the check goal by default runs in the verify phase, we want to fail the build if mimimum code coverage checks aren't met -->
\n          <execution>
\n            <id>check<\/id>
\n            <goals>
\n              <goal>check<\/goal>
\n            <\/goals>
\n            <configuration>
\n              <rules>
\n                <!-- All classes must have 80% line and branch coverage . Note we use 2 d.p so that we get can any check failure messages reported to 2 d.p  -->
\n                <rule >
\n                  <element>CLASS<\/element>
\n                  <limits>
\n                    <limit >
\n                      <counter>LINE<\/counter>
\n                      <value>COVEREDRATIO<\/value>
\n                      <minimum>0.80<\/minimum>
\n                    <\/limit>
\n                    <limit >
\n                      <counter>BRANCH<\/counter>
\n                      <value>COVEREDRATIO<\/value>
\n                      <minimum>0.80<\/minimum>
\n                    <\/limit>
\n                  <\/limits>
\n                  <excludes>
\n                    <exclude>com.choudhury.codecoverage.Bye<\/exclude>
\n                  <\/excludes>
\n                <\/rule>
\n              <\/rules>
\n            <\/configuration>
\n          <\/execution>
\n        <\/executions><\/div><\/div>\n

Example Project<\/strong><\/p>\n

Example maven project can be found here<\/a><\/p>\n

With the example project, when we run “mvn clean install” we expect to fail on code coverage checks.<\/p>\n

To confirm that Jacoco agent is correctly being appended to the Java argLine for maven SureFire plugin, temporarily put a long enough pause in the Unit Test (and whilst the Unit Test are running) launch jvisualvm <\/strong>to check that jacoco is correctly setup as an agent.<\/p>\n

\"jacoco_run_as_agent\"<\/a><\/p>\n

\"min_check_failed\"<\/a><\/p>\n

If we update the HelloTest to test the missed branch and re-run “mvn clean install” we should see the lines “All Coverage checks have been met”<\/strong> to appear and the the build should pass \ud83d\ude42<\/p>\n

\"min_check_passed\"<\/a><\/p>\n

JaCoCo Code Coverage Reports<\/strong><\/p>\n

Another nice feature of JaCoCo maven plugin is the report<\/a> goal allowing you to see which lines have been covered by your tests.<\/p>\n

Execute the report goal of the JaCoCo maven plugin<\/p>\n

mvn jacoco:report<\/div><\/div>\n

(Note : <\/strong> this reads the jacoco.exec file in your target folder, do make sure it’s present when you run this goal, otherwise you will get no reports produced).<\/p>\n

The report goal should produce the html files under target\/site\/jacoco folder.<\/p>\n

\"\"<\/a><\/p>\n