The CoverageMergerTask merges code coverage information from external sources with an existing code coverage database.

The format of the code coverage files is expected to be identical to:

file_put_contents(
        '/www/live/testcases/coverage.data', serialize(xdebug_get_code_coverage)
        );

<coverage-merger>
  <fileset dir="/www/live/testcases">
    <include name="**/*.data"/>
  </fileset>
</coverage-merger>