core-it-support/maven-it-sample/src/test/resources/mng-xxxx/checkstyle-test/pom.xml

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

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<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
  <modelVersion>4.0.0</modelVersion>

  <parent>
    <groupId>org.apache.maven.its.itsample</groupId>
    <artifactId>parent</artifactId>
    <version>1</version>
  </parent>

  <artifactId>checkstyle-test</artifactId>

  <name>Checkstyle Test</name>

  <build>

    <!--This extension is installed by the IT prior to invoking this build. See ../checkstyle-assembly-->
    <extensions>
      <extension>
        <groupId>org.apache.maven.its.itsample</groupId>
        <artifactId>checkstyle-assembly</artifactId>
        <version>1.0</version>
      </extension>
    </extensions>

  <!-- Typically the tests will not rely on actual plugins and should be self-contained, in this case the problem was most
  often experienced with Checkstyle so it makes it a valid test. Notice however that it is pinned to a known released version 
  so the test won't randomly fail in the future if the plugin behavior changes.
  
  If the extension listed above isn't correctly installed on the plugin classpath, this invocation will fail to find the custom rule -->
    <plugins>
      <plugin>
        <groupId>org.apache.maven.plugins</groupId>
        <artifactId>maven-checkstyle-plugin</artifactId>
        <version>2.1</version>
        <inherited>true</inherited>
        <executions>
          <execution>
            <id>STC Checks</id>
            <phase>verify</phase>
            <goals>
              <goal>checkstyle</goal>
            </goals>
            <configuration>
              <configLocation>stc_checks.xml</configLocation>
              <failsOnError>true</failsOnError>
              <cacheFile>${project.build.directory}/checkstyle-cachefile</cacheFile>
              <consoleOutput>true</consoleOutput>
            </configuration>
          </execution>
        </executions>
      </plugin>
    </plugins>
  </build>
</project>