Unknown type of bot/dialog error when extending botbuilder dialog classes

[SeanSobey]

Example

const unit = require("botbuilder-unit");
const botbuilder = require("botbuilder");

const script = [];
class TestDialog extends botbuilder.SimpleDialog {
    constructor() {
        super(() => { });
    }
}
const dialog = new TestDialog();
unit(dialog, script, {
    title: 'Your first test script',
    reporter: new unit.BeautyLogReporter()
}).then(() => {
    console.log('Script passed');
}, (err) => {
    console.error(err);
});

Results in :

Error: Unknown type of bot/dialog. Error: {"actions":{}}

Looking at botbuilder-unit.js resolveBot function:

function resolveBot(bot) {
  let isWaterfall = ("function" == typeof bot) || Array.isArray(bot);
  if (isWaterfall) {
    let dialog = bot;
    let connector = new TestConnector();
    bot = new builder.UniversalBot(connector);
    bot.dialog('/', dialog);
  } else if (bot instanceof builder.UniversalBot) {
    if ( !bot.connector()) {
      bot.connector('console', new TestConnector());
    }
  } else {
    throw new Error(`Unknown type of bot/dialog. Error: ${JSON.stringify(bot)}`);
  }
  return bot;
}

Could maybe check for instanceof builder.Dialog, eg:

let isWaterfall = ("function" == typeof bot) || Array.isArray(bot);
let isDialog = bot instanceof builder.Dialog;
if (isWaterfall || isDialog) {
 ...

Would you consider a pull request?