code: @Then("^I save selenium dcos acs auth cookie in variable '(.+?)'$")
      public void getDcosAcsAuthCookie(String envVar) throws Exception {
          if (commonspec.getSeleniumCookies() != null && commonspec.getSeleniumCookies().size() != 0) {
              for (Cookie cookie: commonspec.getSeleniumCookies()) {
                  if (cookie.getName().contains("dcos-acs-auth-cookie")) {
                      //It's this cookie where we have to extract the value
                      ThreadProperty.set(envVar, cookie.getValue());
                      break;
                  }
              }
          } else {
              ThreadProperty.set(envVar, null);
          }
      }
docs: Get dcos-auth-cookie