remix-project/test-browser/commands/signMessage.js

const EventEmitter = require('events')

class SelectContract extends EventEmitter {
  command (msg) {
    this.api.perform((done) => {
      signMsg(this.api, msg, (hash, signature) => {
        done()
        this.emit('complete')
      })
    })
    return this
  }
}

function signMsg (browser, msg, cb) {
  let hash, signature
  browser
      .waitForElementPresent('i[id="remixRunSignMsg"]')
      .click('i[id="remixRunSignMsg"]')
      .waitForElementPresent('textarea[id="prompt_text"]')
      .setValue('textarea[id="prompt_text"]', msg, () => {
        browser.modalFooterOKClick().perform(
          (client, done) => {
            browser.getText('span[id="remixRunSignMsgHash"]', (v) => { hash = v; done() })
          }
        )
        .perform(
          (client, done) => {
            browser.getText('span[id="remixRunSignMsgSignature"]', (v) => { signature = v; done() })
          }
        )
        .modalFooterOKClick()
        .perform(
          () => {
            cb(hash, signature)
          }
        )
      })
}

module.exports = SelectContract