tests/org.eclipse.core.tests.runtime/Plugin_Testing/circular/tests.b.xml

<?xml version="1.0" encoding="UTF-8"?>
<plugin
  name="IBM Tooling Platform Core Tests"
  id="tests.b"
  version="1.2"
  vendor-name="IBM">

  <requires>
     <import plugin="tests.a"/>
  </requires>

</plugin>