private void startServer(String name, String classPath, int locatorPort, GfshExecutor gfsh,
      Path serverDir) {
    CommandStringBuilder command = new CommandStringBuilder(CliStrings.START_SERVER);
    command.addOption(CliStrings.START_SERVER__NAME, name);
    command.addOption(CliStrings.START_SERVER__SERVER_PORT, "0");
    command.addOption(CliStrings.START_SERVER__CLASSPATH, classPath);
    command.addOption(CliStrings.START_SERVER__LOCATORS, "localhost[" + locatorPort + "]");
    command.addOption(CliStrings.START_SERVER__DIR, serverDir.toString());

    gfsh.execute(GfshScript.of(command.toString()).expectExitCode(0));
  }
This test iterates through the versions of Geode and executes session client compatibility with
the current version of Geode.
geode-assembly/src/upgradeTest/java/org/apache/geode/session/tests/Tomcat8ClientServerRollingUpgradeTest.java