public static void launchIfNeeded(boolean launchLocator) {
    if (System.getProperties().contains(VM_NUM_PARAM)) {
      // we're a dunit child vm, do nothing.
      return;
    }

    if (!isHydra() && !isLaunched()) {
      try {
        launch(launchLocator);
      } catch (Exception e) {
        throw new RuntimeException("Unable to launch dunit VMs", e);
      }
    }

    Host.setAllVMsToCurrentVersion();
  }
Launch DUnit. If the unit test was launched through the hydra framework, leave the test alone.
geode-dunit/src/main/java/org/apache/geode/test/dunit/internal/DUnitLauncher.java