Hermione

Hermione is a utility for integration testing of web pages using WebdriverIO v7 and Mocha.

• Why you should choose hermione
  • Easy to use
  • Runs tests in parallel
  • Runs tests in subprocesses
  • Extensible
  • Retries failed tests
  • Executes separate tests
  • Skips tests in specific browsers
  • Override browser configuration for test
    • version(<browserVersion>)
  • Offers flexible test configuration
  • Automatically initializes and closes grid sessions
  • Fairly waits for screen rotate
• Prerequisites
• Tests API
  • Hooks
  • Skip
  • Only
  • Config overriding
    • testTimeout
  • WebdriverIO extensions
    • Sharable meta info
    • Execution context
  • AssertView
• Quick start
• .hermione.conf.js
  • sets
  • browsers
    • desiredCapabilities
    • gridUrl
    • baseUrl
    • httpTimeout
    • urlHttpTimeout
    • pageLoadTimeout
    • sessionRequestTimeout
    • sessionQuitTimeout
    • testTimeout
    • waitTimeout
    • sessionsPerBrowser
    • screenshotOnReject
    • screenshotOnRejectTimeout
    • testsPerSession
    • retry
    • shouldRetry
    • calibrate
    • meta
    • windowSize
    • screenshotDelay
    • orientation
    • waitOrientationChange
    • resetCursor
    • tolerance
    • antialiasingTolerance
    • compareOpts
    • buildDiffOpts
    • assertViewOpts
    • screenshotsDir
    • strictTestsOrder
    • compositeImage
    • screenshotMode
    • saveHistoryOnTestTimeout
    • saveHistoryOnError
  • system
    • debug
    • mochaOpts
    • ctx
    • patternsOnReject
    • workers
    • testsPerWorker
    • parallelLimit
    • fileExtensions
  • plugins
    • Parallel execution plugin code
  • prepareBrowser
  • prepareEnvironment
• CLI
  • Reporters
  • Require modules
  • Overriding settings
  • Environment variables
    • HERMIONE_SKIP_BROWSERS
  • Debug mode
• Programmatic API
  • init
  • run
  • addTestToRun
  • readTests
  • isFailed
  • isWorker
  • halt
  • Test Collection
  • Test Parser API
    • setController(name, methods)
    • events

Why you should choose hermione

Hermione provides several features that WebdriverIO doesn't, and makes the testing process easier.

Easy to use

If you are familiar with WebdriverIO and Mocha, you can start writing and running tests in 5 minutes! You need to install hermione via npm and add a tiny config to your project. For details, see the Quick start section.

Runs tests in parallel

When tests are run one by one, it takes a lot of time. Hermione can run tests in parallel sessions in different browsers out of the box.

Runs tests in subprocesses

Running of too many tests in parallel can lead to the overloading of the main process CPU usage which causes degradation in test passing time, so Hermione runs all tests in subprocesses in order to solve this problem.

Extensible

WebdriverIO provides built-in commands for browser and page manipulation. Often projects need to store some common code and reuse it throughout all tests, so the developer needs to create some helpers and include them in the tests.

With hermione this is very simple and straightforward. You can add any number of custom commands in the hermione config and use them as this.browser.myCustomCommand in tests.

Moreover, hermione provides plugins that work like hooks. They allow the developer to prepare the testing environment and react properly to test execution events.

Retries failed tests

Integration tests use a dynamic environment with a lot of dependencies, where any of them could be unstable from time to time. As a result, integration tests turn red randomly, which makes them imprecise. This spoils the entire testing process.

To prevent incidental fails, hermione retries a failed test before marking it as failed. This makes it possible to get rid of a majority of incidental fails. The number of retries can be specified for all browsers or for a specific browser.

⚠️ Hermione reruns tests in a new browser session to exclude situations when the browser environment is the cause of the failure.

Executes separate tests

Sometimes you only need to run specific tests, not all the tests in a set. Hermione makes this possible. You can specify the path to the test file

hermione tests/func/mytest.js

or filter describes by using the --grep option

hermione --grep login

or simply use the mocha only() API in the test

describe.only('user login', function() {...});

Skips tests in specific browsers

Sometimes you need to skip a test just in a specific browser, not in all browsers. For example, you don't need to run some test in ugly IE browsers. In hermione you can do this with hermione helper. For example, you can skip some tests in a specific browser

describe('feature', function() {
    hermione.skip.in('ie8', 'it cannot work in this browser');
    it('nowaday functionality', function() {...});
});

or run tests in just one browser

describe('feature', function() {
    // will be skipped in all browsers except Chrome
    hermione.skip.notIn('chrome', 'it should work only in Chrome');
    it('specific functionality', function() {...});
});

In these cases you will see messages in reports with the reason for skipping.

To skip a suite or test silently (without any messages in reports), you can pass the third argument with the silent flag:

hermione.skip.in('ie8', 'skipReason', {silent: true});
// or
hermione.skip.notIn('chrome', 'skipReason', {silent: true});

Or you can use another hermione helper, only, which is silent by default:

hermione.only.in('chrome');
// or
hermione.only.notIn('ie8');

hermione.only.in will run tests only in the specified browsers and skip the rest silently.

hermione.only.notIn will run tests in all browsers except the specified ones.

Override browser configuration for test

Hermione allows you to override a browser configuration for each test or a whole suite. Each method of hermione.browser(<browserName>) provide chaining.

version(<browserVersion>)

// change the browser version for all chindren
hermione.browser('chrome').version('70.3');
describe('suite', function() {
    // ...
});

// change the browser version for a specific test
hermione.browser('chrome').version('70.3');
it('test', function() {...});

hermione.browser('chrome').version('70.3');
describe('suite', function() {
    it('test 1', function() {...});

    // this call will override the version only for test below
    hermione.browser('chrome').version('70.1');
    it('test 2', function() {...});
});

Offers flexible test configuration

Hermione lets you configure running some set of tests in specific browsers. For example,

sets: {
    desktop: {
        files: 'tests/desktop',
        browsers: ['ie8', 'opera']
    },
    touch: {
        files: 'tests/touch',
        browsers: ['iphone', 'android']
    }
}

See sets for more details.

Automatically initializes and closes grid sessions

All work with the grid client is encapsulated in hermione. Forget about client.init and client.end in your tests ;)

Fairly waits for screen rotate

Request /session/:sessionId/orientation is not a part of the official Webdriver specification, so commands orientation and setOrientation which are provided by client webdriverio from the box do not guarantee screen rotate before the next command will start to execute, but Hermione solves this problem.

Prerequisites

Because hermione is based on WebdriverIO, you need to set up Selenium before proceeding further.

The simplest way to get started is to use one of the NPM selenium standalone packages, such as vvo/selenium-standalone. After installing it (globally), you can install drivers by command

selenium-standalone install

and run your server by executing

selenium-standalone start

⚠️ If you will get error like No Java runtime present, requesting install. you should install Java Development Kit (JDK) for your OS.

Tests API

Hooks

before and after hooks are forbidden in hermione, you should use beforeEach and afterEach hooks instead. This feature was implemented in order to ensure better stability while running tests and make them independent of each other.

Skip

This feature allows you to ignore the specified suite or test in any browser, with an additional comment. You can do this by using the global hermione.skip helper. It supports the following methods:

• .in – Adds matchers for browsers with the additional comment.
• .notIn – .in method with the reverted value.

Each of these methods takes the following arguments:

• browser {String|RegExp|Array<String|RegExp>} – Matcher for browser(s) to skip.
• [comment] {String} – Comment for skipped test.
• [options] {Object} – Additional options.

Note that matchers will be compared with browserId specified in the config file, e.g. chrome-desktop.

For example,

describe('feature', function() {
    hermione.skip.in('chrome', "It shouldn't work this way in Chrome");
    it('should work this way', function() {
        return runTestThisWay();
    });

    it('should work that way', function() {
        return runTestThatWay();
    });

    hermione.skip.in(['chrome', 'firefox', /ie\d*/], 'Unstable test, see ticket TEST-487');
    it('should have done some tricky things', function() {
        return runTrickyTest();
    });
});

In this case, the behaviour it should work this way will be skipped only in chrome browser, but will be run in other browsers. It should work that way will not be ignored. So only the nearest test will be skipped. If you need to skip all tests within a suite, you can apply the skip helper to a describe so all tests within this suite will be skipped with the same comment.

hermione.skip.in('chrome', 'skip comment');
describe('some feature', function() {
    it(...);
    it(...);
});

You can also use the .notIn method to invert matching. For example,

// ...
hermione.skip.notIn('chrome', 'some comment');
it('should work this way', function() {
    return doSomething();
});
// ...

In this case, the test will be skipped in all browsers except chrome.

All of these methods are chainable, so you can skip a test in several browsers with different comments. For example,

// ...
hermione.skip
    .in('chrome', 'some comment')
    .notIn('ie9', 'another comment');
it('test1', function() {
    return doSomething();
});
// ...

If you need to skip a test in all browsers without a comment, you can use mocha .skip method instead of hermione.skip.in(/.*/);. The result will be the same.

Only

This feature allows you to ignore the specified suite or test in any browser silently (without any messages in reports). You can do this by using the global hermione.only helper. It supports two methods:

• .in — The hermione.skip.notIn method with the silent flag,
• .notIn — The hermione.skip.in with the silent flag.

These methods take the following arguments:

• browser {String|RegExp|Array<String|RegExp>} — A matcher for browser(s) to skip.

For example:

// ...
hermione.only.in('chrome');

it('should work this way', function() {
    return doSomething();
});

The test will be skipped all browsers silently except in chrome.

hermione.only.notIn('ie9');
it('should work another way', function() {
    return doSomething();
});

The test will be processed in all browsers and silently skipped in ie9.

Config overriding

You can override some config settings for specific test, suite or hook via hermione.config.* notation.

testTimeout

Overrides testTimeout config setting. Can be set for tests and suites.

hermione.config.testTimeout(100500);
it('some test', function() {
    return doSomething();
});

WebdriverIO extensions

Hermione adds some useful methods and properties to the webdriverio session after its initialization.

Sharable meta info

Implemented via two commands:

• setMeta(key, value)
• getMeta([key])

These methods allow you to store some information between webdriver calls and it can then be used in custom commands, for instance. This meta information will be shown in the html-reporter.

Note: hermione saves the last URL opened in the browser in meta info.

Example:

it('test1', function() {
    return this.browser
        .setMeta('foo', 'bar')
        .url('/foo/bar?baz=qux')
        .getMeta('foo')
        .then((val) => console.log(val)) // prints 'bar'
        .getMeta('url')
        .then((url) => console.log(url)) // prints '/foo/bar?baz=qux'
        .getMeta()
        .then((meta) => console.log(meta)) // prints `{foo: 'bar', url: '/foo/bar?baz=qux'}`
});

Execution context

The execution context can be accessed by the browser.executionContext property, which contains the current test/hook mocha object extended with the browser id.

Example:

it('some test', function() {
    return this.browser
        .url('/foo/bar')
        .then(function() {
            console.log('test', this.executionContext);
        });
});

will print something like this

test: {
  "title": "some test",
  "async": 0,
  "sync": true,
  "timedOut": false,
  "pending": false,
  "type": "test",
  "body": "...",
  "file": "/foo/bar/baz/qux.js",
  "parent": "#<Suite>",
  "ctx": "#<Context>",
  "browserId": "chrome",
  "meta": {},
  "timer": {}
}

AssertView

Command that adds ability to take screenshot for test state. Each state should have his own unique name. For example:

it('some test', function() {
    return this.browser
        .url('some/url')
        .assertView('plain', '.button')
        .click('.button')
        .assertView('clicked', '.button');
});

Parameters:

• state (required) String – state name; should be unique within one test
• selector (required) String|String[] – DOM-node selector that you need to capture
• opts (optional) Object:
  • ignoreElements (optional) String|String[] – elements, matching specified selectors will be ignored when comparing images
  • tolerance (optional) Number – overrides config browsers.tolerance value
  • antialiasingTolerance (optional) Number – overrides config browsers.antialiasingTolerance value
  • allowViewportOverflow (optional) Boolean – by default Hermione throws an error if element is outside the viewport bounds. This option disables check that element is outside of the viewport left, top, right or bottom bounds. In this case only visible part of the element will be captured. But if set browser option compositeImage with true value, then in the resulting screenshot will appear the whole element with not visible parts outside of the viewport.
  • captureElementFromTop (optional) Boolean - ability to set capture element from the top area or from current position. In the first case viewport will be scrolled to the top of the element. Default value is true
  • compositeImage (optional) Boolean - overrides config browsers.compositeImage value
  • screenshotDelay (optional) Number - overrides config browsers.screenshotDelay value

All options inside assertView command override the same options in the browsers.assertViewOpts.

Full example:

it('some test', function() {
    return this.browser
        .url('some/url')
        .assertView(
            'plain', '.form',
            {
                ignoreElements: ['.link'],
                tolerance: 5,
                antialiasingTolerance: 4,
                allowViewportOverflow: true,
                captureElementFromTop: true,
                compositeImage: true,
                screenshotDelay: 10
            }
        );
});

For tests which have been just written using assertView command you need to update reference images, so for the first time hermione should be run with option --update-refs or via command gui which is provided by plugin html-reporter (we highly recommend to use gui command instead of option --update-refs).

Quick start

First of all, make sure that all prerequisites are satisfied.

Install the package.

npm install hermione chai

Then put .hermione.conf.js in the project root.

module.exports = {
    sets: {
        desktop: {
            files: 'tests/desktop'
        }
    },

    browsers: {
        chrome: {
            desiredCapabilities: {
                browserName: 'chrome' // this browser should be installed on your OS
            }
        }
    }
};

Write your first test in tests/desktop/github.js file.

const assert = require('chai').assert;

describe('github', function() {
    it('should find hermione', function() {
        return this.browser
            .url('https://github.com/gemini-testing/hermione')
            .getText('#readme h1')
            .then(function(title) {
                assert.equal(title, 'Hermione')
            });
    });
});

Finally, run tests (be sure that you have already run selenium-standalone start command in next tab).

node_modules/.bin/hermione

.hermione.conf.js

hermione is tuned using a configuration file. By default, it uses .hermione.conf.js, but you can use the --config option to specify a path to the configuration file.

There is only one required field – browsers.

module.exports = {
    browsers: {
        chrome: {
            desiredCapabilities: {
                browserName: 'chrome'
            }
        }
    }
};

sets

You can use sets to bind some set of tests to certain browsers.

Format of the sets section:

sets: {
    common: {                 // run tests associated with this path in all browsers
        files: 'tests/common' // which are configured in the `browsers` option
    },
    desktop: {
        files: [
            'tests/desktop/*.hermione.js',
            'tests/common/*.hermione.js'
        ],
        ignoreFiles: ['tests/desktop/fixtures/**'], // exclude directories from reading while test finding
        browsers: ['browser'] // run tests which match the specified masks in the browser with the `browser` id
    }
}

• files – A list of test files or directories with test files. This can be a string if you want to specify just one file or directory. Also, you can use masks for this property.

• ignoreFiles - A list of paths or masks to ignore from reading while test finding. When you write !**/some-dir/** it means that the directory will be read, but all the entries will not be included in the results. So using ignoreFiles you can speed up test reading for your project.

• browsers – A list of browser IDs to run the tests specified in files. All browsers by default.

You can specify sets to run using the CLI option --set.

If sets are not specified in the config and paths were not passed from CLI, all files from the hermione directory are launched in all browsers specified in the config.

Running tests using sets:

hermione --set desktop

browsers

Required. The list of browsers to use for running tests.

The browser section has the following format

browsers: {
    <browser_id>: {
        <option>:<value>
        <option>:<value>
    }
}

<browser-id> value is used for browser identification.

Available browser options:

Option name	Description
desiredCapabilities	Required. Used WebDriver DesiredCapabilities
gridUrl	Selenium grid URL. Default value is http://localhost:4444/wd/hub.
baseUrl	Base service-under-test URL. Default value is http://localhost.
automationProtocol	Browser automation protocol. Default value is webdriver.
sessionEnvFlags	Environment flags that determine which protocol will be used in created browser session. Default value is {}.
waitTimeout	Timeout for web page event. Default value is 1000 ms.
waitInterval	Interval for web page event. Default value is 250 ms.
httpTimeout	Timeout for any requests to Selenium server. Default value is 90000 ms.
urlHttpTimeout	Timeout for /url request to Selenium server. Default value is httpTimeout.
pageLoadTimeout	Timeout for the page loading to complete. Default value is 300000 ms.
sessionRequestTimeout	Timeout for getting a browser session. Default value is httpTimeout.
sessionQuitTimeout	Timeout for quitting a session. Default value is httpTimeout.
testTimeout	Timeout for test execution (in milliseconds). Default value is null, in this case will be used common timeout for all browsers from system.mochaOpts.timeout.
sessionsPerBrowser	Number of sessions which are run simultaneously. Default value is 1.
screenshotOnReject	Allows to attach a screenshot of a current page on test fail. Default value is true.
screenshotOnRejectTimeout	Timeout for taking screenshot on test fail. Default value is httpTimeout.
testsPerSession	Maximum amount of tests (its) to run in each web driver session.
retry	How many times a test should be rerun. Default value is 0.
shouldRetry	Function that determines whether to make a retry. By default returns trueif retry attempts are available otherwise returns false.
calibrate	Allows to correctly capture the image. Default value is false.
meta	Additional data that can be obtained via .getMeta() method.
windowSize	Browser window dimensions. Default value is null.
screenshotDelay	Allows to specify a delay (in milliseconds) before making any screenshot.
orientation	Browser orientation that will be set before each test run. Default value is null.
waitOrientationChange	Allows to wait until screen orientation is changed. Default value is true.
resetCursor	Allows to configure whether to move mouse cursor to body coordinates (0, 0) before each test run.
tolerance	Maximum allowed CIEDE2000 difference between colors. Default value is 2.3.
antialiasingTolerance	Minimum difference in brightness between the darkest/lightest pixel (which is adjacent to the antiasing pixel) and theirs adjacent pixels. Default value is 0.
compareOpts	Options for comparing images.
buildDiffOpts	Options for building diff image.
assertViewOpts	Options for assertView command, used by default.
screenshotsDir	Directory to save reference images for command assertView. Default dir is hermione/screens which is relative to process.cwd().
strictTestsOrder	hermione will guarantee tests order in readTests results. false by default.
compositeImage	Allows testing of regions which bottom bounds are outside of a viewport height (default: false). In the resulting screenshot the area which fits the viewport bounds will be joined with the area which is outside of the viewport height.
screenshotMode	Image capture mode.
saveHistoryOnTestTimeout	Save history of all executed commands in the error object on test timeout. false by default.
saveHistoryOnError	Save history of all executed commands in the error object on any error. false by default.
agent	Allows to use a custom http/https/http2 agent to make requests. Default value is null.
headers	Allows to set custom headers to pass into every http-request. Default value is null.
transformRequest	Allows to intercept HTTP request options before a WebDriver request is made. Default value is null.
transformResponse	Allows to intercept HTTP response object after a WebDriver response has arrived. Default value is null.
strictSSL	Whether it does require SSL certificate to be valid. Default value is null (it means that will be used default value from wdio).
user	Cloud service username. Default value is null.
key	Cloud service access key or secret key. Default value is null.
region	Ability to choose different datacenters for run in cloud service. Default value is null.
headless	Ability to run headless browser in cloud service. Default value is null.

desiredCapabilities

Required. Used WebDriver DesiredCapabilities. For example,

'chrome': {
  desiredCapabilities: {
    browserName: 'chrome',
    version: '75.0', // or "browserVersion" if browser support w3c
    chromeOptions: {...}
  }
}

gridUrl

Selenium grid URL. Default value is http://localhost:4444/wd/hub.

baseUrl

Base service-under-test URL. Default value is http://localhost.

automationProtocol

Browser automation protocol (webdriver, devtools) that will be used. Default value is webdriver.

sessionEnvFlags

Environment flags that determine which protocol will be used in created browser session. By default environment flags are set automatically according to the used desiredCapabilities but in rare cases they are determined inaccurately and using this option they can be overriden explicitly.

Available flags:

• isW3C - should apply WebDriverProtocol or use default JsonWProtocol;
• isChrome - should apply ChromiumProtocol;
• isMobile - should apply MJsonWProtocol and AppiumProtocol;
• isSauce - should apply Sauce Labs specific vendor commands;
• isSeleniumStandalone - should apply special commands when running tests using Selenium Grid or Selenium Standalone server;

For example:

'chrome': {
    sessionEnvFlags: {
        isW3C: true,
        isChrome: true
    }
}

httpTimeout

Timeout for any requests to Selenium server. Default value is 90000 ms.

urlHttpTimeout

Timeout for /url request to Selenium server. Default value is httpTimeout. It may be useful when opening url takes a long time (for example a lot of logic is executed in middlewares), and you don't want to increase timeout for other commands.

pageLoadTimeout

Timeout for the page loading to complete. Default value is 300000 ms.

sessionRequestTimeout

Timeout for getting a browser session. Default value is httpTimeout.

sessionQuitTimeout

Timeout for quitting a session. Default value is httpTimeout.

testTimeout

Timeout for test execution (in milliseconds). If applied to suite then timeout will be set for all tests and hooks inside this suite. Default value is null, in this case will be used common timeout for all browsers from system.mochaOpts.timeout.

waitTimeout

Timeout for web page events. Default value is 1000 ms.

waitInterval

Interval for web page events. Default value is 250 ms.

sessionsPerBrowser

Number of sessions which are run simultaneously. Global value for all browsers. Default value is 1.

screenshotOnReject

Allows to attach a screenshot of a current page on test fail. Default value is true.

screenshotOnRejectTimeout

Timeout for taking screenshot on test fail. Default value is httpTimeout.

testsPerSession

Maximum amount of tests (its) to run in each web driver session. After limit is reached, session will be closed and new one will be started. By default is Infinity (no limit, all tests will be run in the same session). Set to smaller number in case of problems with stability.

retry

How many times a test should be retried if it fails. Global value for all browsers. Default value is 0.

shouldRetry

Function that determines whether to make a retry. Must return boolean value. By default returns true if retry attempts are available otherwise returns false. Argument of this function is object with fields:

• retriesLeft {Number} — number of available retries
• ctx — in case of test TEST_FAIL it would be bound data, in case of ERROR it would be link to Runnable
• [error] — error type (available only in case of ERROR)

calibrate

Does this browser need to perform the calibration procedure. This procedure allows to correctly capture the image in case the particular WebDriver implementation captures browser UI along with web page. Default value is false.

meta

Additional data that can be obtained via .getMeta() method

windowSize

Browser window dimensions (i.e. 1600x1200). If not specified, the size of the window depends on WebDriver. Can be specified as string with pattern 800x1000 or object with width and height keys (both keys should be number). For example,

windowSize: '800x1000'

and

windowSize: {
  width: 800,
  height: 1000
}

are the same.

⚠️ You can't set specific resolutions for browser Opera or mobile platforms. They use only full-screen resolution.

screenshotDelay

Allows to specify a delay (in milliseconds) before making any screenshot. This is useful when the page has elements which are animated or if you do not want to screen a scrollbar. Default value is 0.

orientation

Browser orientation (landscape, portrait) that will be set before each test run. It is necessary in order to return the browser orientation to the default state after test execution in which orientation is changed. Default value is null.

waitOrientationChange

Allows to wait until screen orientation is changed. Works inside webdriverio commands orientation and setOrientation. This option guarantee that screen rotated before the next command will start to execute. Default value is true.

resetCursor

Allows to configure whether to move mouse cursor to body coordinates (0, 0) before each test run. This can be useful to escape cases when a default position of a cursor affects your tests. We recommend to set this option truthy value for desktop browsers and falsey for mobile devices. Default value is true.

tolerance

Indicates maximum allowed CIEDE2000 difference between colors. Used only in non-strict mode. By default it's 2.3 which should be enough for the most cases. Increasing global default is not recommended, prefer changing tolerance for particular suites or states instead.

antialiasingTolerance

Read more about this option in looks-same.

compareOpts

Extra options for comparing images. See looks-same documentation for the list of available options. Default values are:

compareOpts: {
    shouldCluster: false,
    clustersSize: 10,
    stopOnFirstFail: false
}

buildDiffOpts

Extra options for building diff image. See looks-same documentation for the list of available options. Default values are:

buildDiffOpts: {
    ignoreAntialiasing: true,
    ignoreCaret: true
}

assertViewOpts

Default options used when calling assertView, can be overridden by assertView options. Default values are:

    ignoreElements: [],
    captureElementFromTop: true,
    allowViewportOverflow: false

screenshotsDir

Directory to save reference images for command assertView. Default dir is hermione/screens which is relative to process.cwd(). The value of this option can also be a function which accepts one argument - an instance of a test within which comand assertView is called:

    screenshotsDir: (test) => `tests/screenshots/${test.parent.title}`

strictTestsOrder

hermione will guarantee tests order in readTests results. false by default.

compositeImage

Allows testing of regions which bottom bounds are outside of a viewport height (default: false). In the resulting screenshot the area which fits the viewport bounds will be joined with the area which is outside of the viewport height.

screenshotMode

Image capture mode. There are 3 allowed values for this option:

• auto (default). Mode will be obtained automatically;
• fullpage. Hermione will deal with screenshot of full page;
• viewport. Only viewport area will be used.

saveHistoryOnTestTimeout

Allows to save history of all executed commands in the error object on test timeout. false by default.

saveHistoryOnError

Allows to save history of all executed commands in the error object on any error. false by default.

agent

Allows to use a custom http/https/http2 agent to make requests. Default value is null (it means that will be used default http-agent from got).

headers

Allows to set custom headers to pass into every http-request. Default value is null.

transformRequest

Allows to intercept HTTP request options before a WebDriver request is made. Default value is null. If function is passed then it takes RequestOptions as the first argument and should return modified RequestOptions. Example:

(RequestOptions) => RequestOptions

transformResponse

Allows to intercept HTTP response object after a WebDriver response has arrived. Default value is null. If function is passed then it takes Response (original response object) as the first and RequestOptions as the second argument. Should return modified Response. Example:

(Response, RequestOptions) => Response

strictSSL

Whether it does require SSL certificate to be valid. Default value is null (it means that will be used default value from wdio).

user

Cloud service username. Default value is null.

key

Cloud service access key or secret key. Default value is null.

region

Ability to choose different datacenters for run in cloud service. Default value is null.

headless

Ability to run headless browser in cloud service. Default value is null.

system

debug

Turn webdriver debug mode on. Default value is false.

mochaOpts

Extra options for mocha which are passed to mocha.setup. See Mocha documentation for the list of options. Default values are:

mochaOpts: {
    slow: 10000, // If test execution time is greater than this value, then the test is slow.
    timeout: 60000 // timeout for test execution.
}

ctx

A context which will be available in tests via method hermione.ctx:

ctx: {
    foo: 'bar'
}

it('awesome test', function() {
    console.log(hermione.ctx); // {foo: 'bar'}
});

Recommendation: use ctx in your tests in favor of global variables.

patternsOnReject

Session would be rejected if test has been faile with error message which matches to specified patterns:

patternsOnReject: [
    /some-pattern/,
    'other-pattern'
]

workers

Hermione runs all tests in subprocesses in order to decrease the main process CPU usage. This options defines the numbers of subprocesses to start for running tests. Default value is 1.

testsPerWorker

The maximum number of tests to be run in one worker before it will be restarted.

parallelLimit

By default, hermione will run all browsers simultaneously. Sometimes (i.e. when using cloud services, such as SauceLabs) you have to limit the amount of browsers that can be run at the same time. This option effectively limits how many browsers hermione will try to run in parallel. Default value is Infinity.

fileExtensions

Ability to set file extensions, which hermione will search on the file system. Default value is [.js].

plugins

Hermione plugins are commonly used to extend built-in functionality. For example, hermione-allure-reporter and hermione-tunnel.

A plugin is a module that exports a single function. The function has two arguments:

• The hermione instance
• Plugin options from the configuration file

Plugins will be loaded before hermione runs tests.

It's strongly recommended to name hermione plugins with the hermione- prefix. This makes searching for user plugins very simple.

If a plugin name starts with hermione-, then the prefix can be ommited in the configuration file. If two modules with names hermione-some-module and some-module are specified, the module with the prefix will have higher priority.

For example:

// .hermione.conf.js
// ...
plugins: {
    'my-cool-plugin': {
        param: 'value'
    }
}
// ...

// hermione-my-cool-plugin/index.js
module.exports = function(hermione, opts) {
    hermione.on(hermione.events.RUNNER_START, function(runner) {
        return setUp(hermione.config, opts.param); // config can be mutated
    });

    hermione.on(hermione.events.RUNNER_END, function() {
        return tearDown();
    });
}

Properties of the hermione object

Property name	Description
config	Config that is used in the test runner. Can be mutated.
events	Events list for subscription.

Available events which are triggered in the main process

Event	Description
INIT	Will be triggered before any job start (run or readTests). If handler returns a promise then job will start only after the promise will be resolved. Emitted only once no matter how many times job will be performed.
BEFORE_FILE_READ	Will be triggered on test files parsing before reading the file. The handler accepts data object with file, browser (browser id string), hermione (helper which will be available in test file) and testParser (TestParserAPI object) fields.
AFTER_FILE_READ	Will be triggered on test files parsing right after reading the file. The handler accepts data object with file, browser (browser id string) and hermione (helper which will be available in test file) fields.
AFTER_TESTS_READ	Will be triggered right after tests read via readTests or run methods with TestCollection object.
RUNNER_START	Will be triggered after worker farm initialization and before test execution. If a handler returns a promise, tests will be executed only after the promise is resolved. The handler accepts an instance of a runner as the first argument. You can use this instance to emit and subscribe to any other available events.
RUNNER_END	Will be triggered after test execution and before worker farm ends. If a handler returns a promise, worker farm will be ended only after the promise is resolved. The handler accepts an object with tests execution statistics.
NEW_WORKER_PROCESS	Will be triggered after new subprocess is spawned. The handler accepts a restricted process object with only send method.
SESSION_START	Will be triggered after browser session initialization. If a handler returns a promise, tests will be executed only after the promise is resolved. The handler accepts an instance of webdriverIO as the first argument and an object with a browser identifier as the second.
SESSION_END	Will be triggered after the browser session ends. If a handler returns a promise, tests will be executed only after the promise is resolved. The handler accepts an instance of webdriverIO as the first argument and an object with a browser identifier as the second.
BEGIN	Will be triggered before test execution, but after all the runners are initialized.
END	Will be triggered just before RUNNER_END event. The handler accepts a stats of tests execution.
SUITE_BEGIN	Test suite is about to execute.
SUITE_END	Test suite execution is finished.
TEST_BEGIN	Test is about to execute.
TEST_END	Test execution is finished.
TEST_PASS	Test passed.
TEST_FAIL	Test failed.
TEST_PENDING	Test is skipped.
RETRY	Test failed but went to retry.
ERROR	Generic (no tests) errors.
INFO	Reserved.
WARNING	Reserved.
EXIT	Will be triggered when SIGTERM is received (for example, Ctrl + C). The handler can return a promise.

Available events which are triggered in subprocesses

Event	Description
BEFORE_FILE_READ	Will be triggered on test files parsing before reading the file. The handler accepts data object with file, browser (browser id string), hermione (helper which will be available in test file) and testParser (TestParserAPI object) fields.
AFTER_FILE_READ	Will be triggered on test files parsing right after reading the file. The handler accepts data object with file, browser (browser id string) and hermione (helper which will be available in test file) fields.
AFTER_TESTS_READ	Will be triggered right after tests read each time some file is being reading during test run.
NEW_BROWSER	Will be triggered after new browser instance created. The handler accepts an instance of webdriverIO as the first argument and an object with a browser identifier and version as the second.
UPDATE_REFERENCE	Will be triggered after updating reference image.

REMARK!

Events which are triggered in the main process and subprocesses can not share information between each other, for example:

module.exports = (hermione) => {
    let flag = false;

    hermione.on(hermione.events.RUNNER_START, () => {
        flag = true;
    });

    hermione.on(hermione.events.NEW_BROWSER, () => {
        // outputs `false`, because `NEW_BROWSER` event was triggered in a subprocess,
        // but `RUNNER_START` was not
        console.log(flag);
    });

    hermione.on(hermione.events.RUNNER_END, () => {
        // outputs `true`
        console.log(flag);
    });
};

But you can solve such problem this way:

module.exports = (hermione, opts) => {
    hermione.on(hermione.events.RUNNER_START, () => {
      opts.flag = true;
    });

    hermione.on(hermione.events.NEW_BROWSER, () => {
        // outputs `true`, because properties in a config (variable `opts` is a part of a config)
        // which have raw data types are passed to subprocesses after `RUNNER_START` event
        console.log(opts.flag);
    });
};

Besides, you have the ability to intercept events in plugins and translate them to other events:

module.exports = (hermione) => {
    hermione.intercept(hermione.events.TEST_FAIL, ({event, data}) => {
        const test = Object.create(data);
        test.pending = true;
        test.skipReason = 'intercepted failure';

        return {event: hermione.events.TEST_PENDING, data: test};
    });

    hermione.on(hermione.events.TEST_FAIL, (test) => {
        // this event handler will never be called
    });

    hermione.on(hermione.evenst.TEST_PENDING, (test) => {
        // this event handler will always be called instead of 'TEST_FAIL' one
    });
};

If for some reason interceptor should not translate passed event to another one you can return the same object or some falsey value:

module.exports = (hermione) => {
    hermione.intercept(hermione.events.TEST_FAIL, ({event, data}) => {
        return {event, data};
        // return;
        // return null;
        // return false;
    });

    hermione.on(hermione.events.TEST_FAIL, (test) => {
        // this event handler will be called as usual because interceptor does not change event
    });
};

If for some reason interceptor should ignore passed event and do not translate it to any other listeners you can return an empty object:

module.exports = (hermione) => {
    hermione.intercept(hermione.events.TEST_FAIL, ({event, data}) => {
        return {};
    });

    hermione.on(hermione.events.TEST_FAIL, (test) => {
        // this event handler will NEVER be called because interceptor ignores it
    });
};

The above feature can be used to delay triggering of some events, for example:

module.exports = (hermione) => {
  const intercepted = [];

  hermione.intercept(hermione.events.TEST_FAIL, ({event, data}) => {
        intercepted.push({event, data});
        return {};
    });

    hermione.on(hermione.events.END, () => {
        intercepted.forEach(({event, data}) => hermione.emit(event, data));
    });
};

Available events which can be intercepted

Event
SUITE_BEGIN
SUITE_END
TEST_BEGIN
TEST_END
TEST_PASS
TEST_FAIL
RETRY

Parallel execution plugin code

Runner has a method registerWorkers which register plugin's code for parallel execution in Hermione's worker farm. The method accepts parameters workerFilepath (string, absolute path), exportedMethods (array of string) and return object which contains async functions with names from exportedMethods. File with path workerFilepath should export object which contains async functions with names from exportedMethods.

Example

// plugin code
let workers;

module.exports = (hermione) => {
    hermione.on(hermione.events.RUNNER_START, async (runner) => {
        const workerFilepath = require.resolve('./worker');
        const exportedMethods = ['foo'];
        workers = runner.registerWorkers(workerFilepath, exportedMethods);

        // outputs `FOO_RUNNER_START`
        console.log(await workers.foo('RUNNER_START'));
    });

    hermione.on(hermione.events.RUNNER_END, async () => {
        // outputs `FOO_RUNNER_END`
        console.log(await workers.foo('RUNNER_END'));
    });
};

// worker.js
module.exports = {
    foo: async function(event) {
        return 'FOO_' + event;
    }
};

prepareBrowser

Prepare the browser session before tests are run. For example, add custom user commands.

prepareBrowser: function(browser) {
    browser.addCommand('commandName', require('./path/to/commands/commandName.js'));
}

The browser argument is a WebdriverIO session.

prepareEnvironment

Configuration data can be changed depending on extra conditions in the prepareEnvironment function.

CLI

hermione --help

shows the following

  Usage: hermione [options] [paths...]

  Options:

    -V, --version                output the version number
    -c, --config <path>          path to configuration file
    -r, --reporter <reporter>    test reporters
    -b, --browser <browser>      run tests only in specified browser
    -s, --set <set>              run tests only in the specified set
    --require <module>           require a module before running hermione
    --grep <grep>                run only tests matching the pattern
    --update-refs                update screenshot references or gather them if they do not exist ("assertView" command)
    --inspect [inspect]          nodejs inspector on [=[host:]port]
    --inspect-brk [inspect-brk]  nodejs inspector with break at the start
    -h, --help                   output usage information

For example,

hermione --config ./config.js --reporter flat --browser firefox --grep name

Note. All CLI options override config values.

Reporters

You can choose flat or plain reporter by option -r, --reporter. Default is flat.

• flat – all information about failed and retried tests would be grouped by browsers at the end of the report.

• plain – information about fails and retries would be placed after each test.

Require modules

Using --require option you can load external modules, which exists in your local machine, before running hermione. This is useful for:

• compilers such as TypeScript via ts-node (using --require ts-node/register) or Babel via @babel/register (using --require @babel/register);
• loaders such as ECMAScript modules via esm.

Be sure to update fileExtensions apropriately, if you are planning to import anything other than .js.

Overriding settings

All options can also be overridden via command-line flags or environment variables. Priorities are the following:

• A command-line option has the highest priority. It overrides the environment variable and config file value.

• An environment variable has second priority. It overrides the config file value.

• A config file value has the lowest priority.

• If there isn't a command-line option, environment variable or config file option specified, the default is used.

To override a config setting with a CLI option, convert the full option path to --kebab-case. For example, if you want to run tests against a different base URL, call:

hermione path/to/mytest.js --base-url http://example.com

To change the number of sessions for Firefox (assuming you have a browser with the firefox id in the config):

hermione path/to/mytest.js --browsers-firefox-sessions-per-browser 7

To override a setting with an environment variable, convert its full path to snake_case and add the hermione_ prefix. The above examples can be rewritten to use environment variables instead of CLI options:

hermione_base_url=http://example.com hermione path/to/mytest.js
hermione_browsers_firefox_sessions_per_browser=7 hermione path/to/mytest.js

Environment variables

HERMIONE_SKIP_BROWSERS

Skip the browsers specified in the config by passing the browser IDs. Multiple browser IDs should be separated by commas (spaces after commas are allowed).

For example,

HERMIONE_SKIP_BROWSERS=ie10,ie11 hermione

HERMIONE_SETS

Specify sets to run using the environment variable as an alternative to using the CLI option --set.

For example,

HERMIONE_SETS=desktop,touch hermione

Debug mode

In order to understand what is going on in the test step by step, there is a debug mode. You can run tests in this mode using these options: --inspect and --inspect-brk. The difference between them is that the second one stops before executing the code.

Example:

hermione path/to/mytest.js --inspect

Note: In the debugging mode, only one worker is started and all tests are performed only in it. Use this mode with option sessionsPerBrowser=1 in order to debug tests one at a time.

Programmatic API

With the API, you can use Hermione programmatically in your scripts or build tools.

const Hermione = require('hermione');

const hermione = new Hermione(config);

• config (required) String – Path to the configuration file that will be read relative to process.cwd.

init

hermione.init().done();

Initializes hermione instance, load all plugins ans so on.

run

hermione.run(testPaths, options)
    .then((success) => process.exit(success ? 0 : 1))
    .catch((e) => {
        console.log(e.stack);
        process.exit(1);
    })
    .done();

• testPaths (optional) String[]|TestCollection – Paths to tests relative to process.cwd. Also accepts test collection returned by readTests.
• options (optional) Object
  • reporters (optional) String[] – Test result reporters.
  • browsers (optional) String[] – Browsers to run tests in.
  • sets (optional) String[]– Sets to run tests in.
  • grep (optional) RegExp – Pattern that defines which tests to run.

addTestToRun

hermione.addTestToRun(test, browser);

Adds test to the current run.

• test (required) Test – Test to run.
• browserId (required) String – Browser to run test in.

Returns false if current run is ended or cancelled, true otherwise.

readTests

hermione.readTests(testPaths, options).done();

• testPaths (required) String[] – Paths to tests relative to process.cwd.
• options (optional) Object:
  • browsers (optional) String[] – Read tests only for the specified browsers.
  • silent (optional) Boolean – flag to disable events emitting while reading tests; default is false.
  • ignore (optional) String|Glob|Array<String|Glob> - patterns to exclude paths from the test search.

Returns promise which resolves to the instance of TestCollection initialized by parsed tests

isFailed

hermione.isFailed();

Returns true or false depending on whether there has been an error or a test fail while running tests; can be useful in plugins to determine current Hermione status.

isWorker

hermione.isWorker();

Returns true or false depending on whether you call the method in one of the workers or in the master process; can be useful in plugins to share some code execution between the master process and its workers, for example:

// implementation of some plugin
module.exports = (hermione) => {
    if (hermione.isWorker()) {
        // do some stuff only in workers
    } else {
        // do some stuff only in the master process
    }
};

halt

hermione.halt(error, [timeout=60000ms]);

Method for abnormal termination of the test run in case of a terminal error. If process fails to gracefully shutdown in timeout milliseconds, it would be forcibly terminated (unless timeout is explicitly set to 0).

Test Collection

TestCollection object is returned by hermione.readTests method.

TestCollection API:

• getBrowsers() — returns list of browsers for which there are tests in collection.

• mapTests(browserId, (test, browserId) => ...) - maps over tests for passed browser. If first argument (browserId) is omitted then method will map over tests for all browsers.

• sortTests(browserId, (currentTest, nextTest) => ...) - sorts over tests for passed browser. If first argument (browserId) is omitted then method will sort over tests for all browsers.

• eachTest(browserId, (test, browserId) => ...) - iterates over tests for passed browser. If first argument (browserId) is omitted then method will iterate over tests for all browsers.

• eachTestByVersion(browserId, (test, browserId, version) => ...) - iterates over tests and over browser versions for passed browser. Implicitly sets browser version for each test in browserVersion property.

• disableAll([browserId]) - disables all tests. Disables tests for specific browser if browserId passed. Returns current test collection instance.

• enableAll([browserId]) - enables all previously disabled tests. Enables tests for specific browser if browserId passed. Returns current test collection instance.

• disableTest(fullTitle, [browserId]) - disables test with passed full title. Disables test only in specific browser if browserId passed. Returns current test collection instance.

• enableTest(fullTitle, [browserId]) - enables test with passed full title. Enables test only in specific browser if browserId passed. Returns current test collection instance.

• getRootSuite(browserId) - returns root suite for passed browser. Returns undefined if there are no tests in collection for passed browser.

• eachRootSuite((root, browserId) => ...) - iterates over all root suites in collection which have some tests.

Test Parser API

TestParserAPI object is emitted on BEFORE_FILE_READ event. It provides the ability to customize test parsing process.

setController(name, methods)

Adds controller to hermione object in test files.

• name - controller name
• methods - an object with names as keys and callbacks as values describing controller methods. Each callback will be called on corresponding test or suite.

Example:

// in plugin
hermione.on(hermione.events.BEFORE_FILE_READ, ({file, browser, testParser}) => {
    testParser.setController('logger', {
        log: function(prefix) {
            console.log(`${prefix}: Just parsed ${this.fullTitle()} from file ${file} for browser ${browser}`);
        }
    });
});

// in test file
describe('foo', () => {
    hermione.logger.log('some-prefix');
    it('bar', function() {
        // ...
    });
});

Note: controller will be removed as soon as current file will be parsed

events

Parser events list for subscription.

Available events which are triggered in the TestParserAPI

Event	Description
TEST	Will be triggered on test parsing. The handler accepts test instance.
SUITE	Will be triggered on suite parsing. The handler accepts suite instance.
HOOK	Will be triggered on hook parsing. The handler accepts hook instance.

Example:

// in plugin
hermione.on(hermione.events.BEFORE_FILE_READ, ({testParser}) => {
    testParser.on(testParser.events.TEST, (test) => {
        console.log('my awesome test:', test);
    });
});