GEB: set default environment?

I declared a few environments in GebConfig via environments {} closure. And if I specify -Dgeb.env in command line, everything works perfectly.

But when I start a single test for debugging purposes, I don't want to explicitly pass any additional environment variables.

What is the way to define the environment to be used by GEB as a default?

Just define a default driver outside of the environments My Geb config looks like this:

driver = {
  new HtmlUnitDriver(true)
}

environments {
  html_unit {
    driver = {
      new HtmlUnitDriver(true)
    }
  }
  phantomjs {
    driver = {
      WebDriverManager.phantomjs().version("2.1.1").setup()
      def pjsDriver = new PhantomJSDriver()
      pjsDriver.manage().window().size = new Dimension(1024, 768)
      pjsDriver
    }
  }
  chrome {
    driver = {
      // (...)
    }
  }
  chrome_headless {
    System.setProperty("webdriver.chrome.logfile", "chromedriver.log")
    System.setProperty("webdriver.chrome.verboseLogging", "true")
    driver = {
      // (...)
    }
  }
  firefox {
    driver = {
      // (...)
    }
  }
  ie {
    driver = {
      // (...)
    }
  }
  edge {
    driver = {
      // (...)
    }
  }
  opera {
    driver = {
      // (...)
    }
  }
  win_app {
    driver = {
      // (...)
    }
  }
}