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1.5.0-alpha.2 • Public • Published


Wrapper to run nemo/mocha suites

Getting started

Install nemo-runner and nemo

npm install --save-dev nemo nemo-runner

Install chromedriver and GeckoDriver to your $PATH

Add tests directory structure



  "driver": {
    "browser": "phantomjs"
  "data": {
    "baseUrl": "http://localhost:8000"
  "profiles": {
    "base": {
      "tests": "path:spec/*.js",
      "env": {
        "DEBUG": "nemo*"
      "mocha": {
        "timeout": 180000,
        "retries": 0,
        "require": "babel-register",
        "grep": "argv:grep"
    "chrome": {
      "driver": {
        "browser": "chrome"
    "firefox": {
      "driver": {
        "browser": "firefox"


describe('@foo@', _ => {
    it('should @success@fully load a URL', async function () {
        let nemo = this.nemo;
        await nemo.driver.get(;
        await nemo.driver.sleep(3000);
describe('@bar@', _ => {
    it('should @fail@ to load a URL', async function () {
        let nemo = this.nemo;
        await nemo.driver.get('http://localhost/does/not/exist');
        await nemo.driver.sleep(3000);

Add run script(s) to package.json (you can also just run the full command directly but this is cleaner)

"scripts": {
    "start": "node index.js",
    "nemo": "nemo-runner -B test/functional -P firefox,chrome -G @foo@,@bar@",
    "nemo:debug": "nemo-runner --inspect --debug-brk -B test/functional -P firefox -G @foo@"

Give it a try

npm run nemo

You should have seen two Firefox and two Chrome browser instances open and execute the scripts.

CLI arguments

  Usage: _nemo-runner [options]
    -h, --help                   output usage information
    -V, --version                output the version number
    -B, --base-directory <path>  parent directory for config/ and spec/ (or other test file) directories. relative to cwd
    -P, --profile [profile]      which profile(s) to run, out of the configuration
    -G, --grep <pattern>         only run tests matching <pattern>
    -F, --file                   run parallel by file
    -D, --data                   run parallel by data
    --debug-brk                  enable node's debugger breaking on the first line
    --inspect                    activate devtools in chrome
    --no-timeouts                remove timeouts in debug/inspect use case

Profile options


is the main profile configuration that others will merge into


is an absolute path based glob pattern. (e.g. "tests": "path:spec/!(wdb)*.js",)


only valid for 'base'.

  • if set to 'file' it will create a child process for each mocha file (alternative to -F CLI arg)
  • if set to 'data' it will create a child process for each object key under (alternative to the -D CLI arg)


Recommended to set this as path:report, which will create a report directory beneath your base directory. See Reporting below.


mocha options. described elsewhere


any environment variables you want in the test process


a number which represents the max limit of concurrent suites nemo-runner will execute in parallel - if not provided there is no limit


Recommended reporters are mochawesome or xunit. If you use either of these, nemo-runner will generate timestamped directories for each run. The reports will be further separated based on the parallel options. E.g.


In the above example, parallel options were "profile", "file", and "data".

A summary for all parallel instances can be found at summary.json


nemo-runner will take a screenshot automatically after each test execution (pass or fail). The screenshots will be named based on the respective test name. E.g. my awesome test.after.png.

You can use nemo.runner.snap() at any point in a test, to grab a screenshot. These screenshots will be named based on the respective test name, and number of screenshots taken using nemo.runner.snap(). E.g.

  • my awesome test.1.png
  • my awesome test.2.png
  • my awesome test.3.png

If you use the mochawesome reporter, you will see these screeshots in the Additional Context section of the html report.

Adding Nemo into the mocha context and vice versa

nemo-runner injects a nemo instance into the Mocha context (for it, before, after, etc functions) which can be accessed by this.nemo within the test suites.

nemo-runner also adds the current test's context to nemo.mocha. That can be useful if you want to access or modify the test's context from within a nemo plugin.

Parallel functionality

nemo-runner will execute in parallel -P (profile) x -G (grep) mocha instances. The example above uses "browser" as the profile dimension and suite name as the "grep" dimension. Giving 2x2=4 parallel executions.

In addition to profile and grep, are the dimensions file and data.

Parallel by file

file will multiply the existing # of instances by the # of files selected by your configuration.

Parallel by data

data will multiply the existing # of instances by the # of keys found under It can also be overriden per-profile. It will also replace with the value of each keyed object. In other words, you can use this to do parallel, data-driven testing.

If you have the following base profile configuration:

  "profiles": {
    "base": {
      "data": {
        "US": {"url": ""},
        "FR": {"url": ""}
      "parallel": "data",
      "tests": "path:spec/test-spec.js",
      "mocha": {

Then the following test will run twice (in parallel) with corresponding values of

it('@loadHome@', function () {
    var nemo = this.nemo;
    return nemo.driver.get(;//runs once with, once with

Parallel reporting

Using a reporter which gives file output will be the most beneficial. nemo-runner comes out of the box, ready to use mochawesome or xunit for outputting a report per parallel instance.

Mocha options

The properties passed in to the "mocha" property of config.json will be applied to the mocha instances that are created. In general, these properties correlate with the mocha command line arguments. E.g. if you want this:

mocha --timeout 180000

You should add this to the "mocha" property within "profiles" of config.json:

    ...other stuff,
    "mocha": {
        "timeout": 180000

nemo-runner creates mocha instances programmatically. Unfortunately, not all mocha command line options are available when instantiating it this way. One of the arguments that is not supported is the --require flag, which useful if you want to require a module, e.g. babel-register for transpilation. Thus, we added a "require" property in config.json, which takes a string of a single npm module name, or an array of npm module names. If it is an array, nemo-runner will require each one before instantiating the mocha instances.


npm i nemo-runner

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