As the Department of Defense focuses on enabling current forces for global operations; it will be applying significant simulation resources to both force developments and training. The major challenge in creating simulation federations is making sure the federation works when War fighters arrive to use it. The steadily increasing focus on joint force representation within simulation events, both training and experimentation, means that the simulation federations supporting those events grow constantly more complex. As ever more complex simulation federations support joint force development experiments and mission-readiness exercises, the standardization of integration tests permit easier and more detailed checks to ensure diverse simulation federations will work together. Army Capabilities Integration Center (ARCIC) provides TRADOC battle laboratories with the simulation infrastructure for such experiments, and has developed a rigorous program of federation integration to ensure their simulation infrastructure properly supports the experiment objectives. Throughout the last five years, ARCIC has developed phased thread tests to track and measure technical integration of the federation architecture. The use of these innovative thread tests and supporting integration processes have enabled streamlined testing efforts, better utilizing the resources of participating battle laboratories. Thread tests are used throughout the various phases of the integration cycle. Threads can be event and non-event specific, and are archived for future use. In fact, tests threads do not have to be simulation specific, but can be used by any simulation federation, whether training or combat development events. Test threads are viewed as living documents which are continuously improved by gathering feedback, and reviewed by governing technical authorities. The paper reviews how thread tests are used throughout the community, describes the innovative work processes developed for thread-based integration activities, and describes the lessons learned over four years of increasingly complex federation integration. The processes discussed in the paper are non-proprietary and the threads themselves are readily available to the Simulation Community of Practice.