I'm using Maven 3.0.3, JUnit 4.8.1, and Jacoco 0.6.3.201306030806, and I am trying to create test coverage reports.

I have a project with unit tests only, but I can't get reports to run, I'm repeatedly getting the error: Skipping JaCoCo execution due to missing execution data file when I run:

mvn clean install -P test-coverage

Here is how my pom is configured:

<plugin>
  <groupId>org.apache.maven.plugins</groupId>
  <artifactId>maven-surefire-plugin</artifactId>
  <version>2.14.1</version>
  <configuration>
    <reuseForks>true</reuseForks>
    <argLine>-Xmx2048m</argLine>
  </configuration>
</plugin>
<plugin>
  <groupId>org.apache.maven.plugins</groupId>
  <artifactId>maven-failsafe-plugin</artifactId>
  <version>2.14.1</version>
  <configuration>
    <reuseForks>true</reuseForks>
    <argLine>-Xmx4096m -XX:MaxPermSize=512M ${itCoverageAgent}</argLine>
  </configuration>
  <executions>
    <execution>
      <goals>
        <goal>integration-test</goal>
        <goal>verify</goal>
      </goals>
    </execution>
  </executions>
</plugin>
...
<profile>
  <id>test-coverage</id>
  <build>
    <plugins>
      <plugin>
        <groupId>org.jacoco</groupId>
        <artifactId>jacoco-maven-plugin</artifactId>
        <version>0.6.3.201306030806</version>
        <configuration>
          <destfile>${basedir}/target/coverage-reports/jacoco-unit.exec</destfile>
          <datafile>${basedir}/target/coverage-reports/jacoco-unit.exec</datafile>
        </configuration>
        <executions>
          <execution>
            <id>prepare-unit-tests</id>
            <goals>
              <goal>prepare-agent</goal>
            </goals>
          </execution>
          <!-- prepare agent for measuring integration tests -->
          <execution>
            <id>prepare-integration-tests</id>
            <goals>
              <goal>prepare-agent</goal>
            </goals>
            <phase>pre-integration-test</phase>
            <configuration>
              <propertyName>itCoverageAgent</propertyName>
            </configuration>
          </execution>
          <execution>
            <id>jacoco-site</id>
            <phase>verify</phase>
            <goals>
              <goal>report</goal>
            </goals>
          </execution>
        </executions>
      </plugin>
    </plugins>
  </build>
</profile>

All my tests run successfully. Here is some of the output from Maven:

[INFO] --- jacoco-maven-plugin:0.6.2.201302030002:prepare-agent (prepare-unit-tests) @ myproject ---
[INFO] argLine set to -javaagent:/Users/davea/.m2/repository/org/jacoco/
[INFO] 
    ...
Tests run: 14, Failures: 0, Errors: 0, Skipped: 0

[INFO]
    ...
[INFO] 
[INFO] --- jacoco-maven-plugin:0.6.2.201302030002:prepare-agent (prepare-integration-tests) @ myproject ---
[INFO] itCoverageAgent set to -javaagent:/Users/davea/.m2/repository/org/jacoco/ 
[INFO] 
[INFO] --- maven-failsafe-plugin:2.14.1:integration-test (default) @ myproject ---
[WARNING] File encoding has not been set, using platform encoding MacRoman, i.e. build is platform dependent!
[INFO] 
[INFO] --- maven-failsafe-plugin:2.14.1:verify (default) @ myproject ---
[INFO] Failsafe report directory: /Users/davea/Dropbox/workspace/myproject/target/failsafe-reports
[WARNING] File encoding has not been set, using platform encoding MacRoman, i.e. build is platform dependent!
[INFO] 
[INFO] --- jacoco-maven-plugin:0.6.2.201302030002:report (jacoco-site) @ myproject ---
[INFO] Skipping JaCoCo execution due to missing execution data file
[INFO] 

Any ideas what configuration I'm missing?