attachments.md

Attachments

Text, images and other data can be added to the output of the messages and JSON formatters with attachments. The world constructor is passed an attach function, which the default world constructor assigns to this.attach. If using a custom world constructor, you need to do this as well if you want to add attachments.

var {After} = require('cucumber');

After(function () {
  this.attach('Some text');
});

By default, text is saved with a MIME type of text/plain. You can also specify a different MIME type:

var {After} = require('cucumber');

After(function () {
  this.attach('{"name": "some JSON"}', 'application/json');
});

Images and other binary data can be attached using a stream.Readable. The data will be base64 encoded in the output. You should wait for the stream to be read before continuing by providing a callback or waiting for the returned promise to resolve.

var {After, Status} = require('cucumber');

// Passing a callback
After(function (testCase, callback) {
  if (testCase.result.status === Status.FAILED) {
    var stream = getScreenshotOfError();
    this.attach(stream, 'image/png', callback);
  }
  else {
    callback();
  }
});

// Returning the promise
After(function (testCase) {
  if (testCase.result.status === Status.FAILED) {
    var stream = getScreenshotOfError();
    return this.attach(stream, 'image/png');
  }
});

Images and binary data can also be attached using a Buffer. The data will be base64 encoded in the output.

var {After, Status} = require('cucumber');

After(function (testCase) {
  if (testCase.result.status === Status.FAILED) {
    var buffer = getScreenshotOfError();
    this.attach(buffer, 'image/png');
  }
});

Here is an example of saving a screenshot using Selenium WebDriver when a scenario fails:

var {After, Status} = require('cucumber');

After(function (testCase) {
  var world = this;
  if (testCase.result.status === Status.FAILED) {
    return webDriver.takeScreenshot().then(function(screenShot) {
      // screenShot is a base-64 encoded PNG
      world.attach(screenShot, 'image/png');
    });
  }
});

Attachments are also printed by the progress, progress-bar and summary formatters. They appear right after the step and only text/plain content is visible. It can be used to debug scenarios, especially in parallel mode.

// Step definition
Given(/^a basic step$/, function() {
  this.attach('Some info.')
  this.attach('{"some", "JSON"}}', 'application/json')
})

// Result format
// ✔ Given a basic step # path:line
//    Attachment (text/plain): Some info.
//    Attachment (application/json)

Logging

You can log useful information from your support code with the simple log function:

var {After} = require('cucumber');

After(function () {
  this.log('Something interesting happened!');
});

Anything you log will be attached as a string with a MIME type of text/x.cucumber.log+plain