Using the command line - Attester documentation

Using the command line

attester can be used from the command line to execute test campaigns.

It runs your tests on all the required browsers and reports the result in the command line. This can be easily integrated in any build system or continuous integration environment.

attester [<options>] [<configuration file>]

Configuration file

The configuration file describes the campaign to execute. A very detailed description is available at this page


The whole list of options, with a short description, is available with

attester --help

Usual options

  • --phantomjs-path <path> Path to the PhantomJS executable (default: phantomjs). You can follow this guide to install and configure PhantomJS

  • --phantomjs-instances <number> Number of instances of PhantomJS to start (default: 0). Additionally, a string auto can be passed to let the program use the optimal number of instances for best performance (max. 1 per CPU thread).

  • --browser <path> Path to any browser executable to execute the tests. Can be repeated multiple times to start multiple browsers or multiple instances of the same browser. Each browser is started with one parameter: the URL to open to start tests. At the end of the tests, all started processes are killed.

  • --env <path> Path to a yaml or json file containing environment options. See the section about environment variables.

  • --ignore-errors When enabled, test errors (not including failures) will not cause this process to return a non-zero value.

  • --ignore-failures When enabled, test failures (anticipated errors) will not cause this process to return a non-zero value.

  • --port <number> Port used for the internal web server. By default it tries to use port 7777 and will choose an available port automatically if the one specified is not available.

  • --server-only Only starts the web server, and configure it for the test campaign but do not start the campaign. This is useful to run tests manually or display coverage reports of old campaigns.

  • --log-level <number> Level of logging: integer from 0 (no logging) to 4 (debug).

  • --colors Uses colors (disable with --no-colors).

  • --help Displays a help message and exits.

  • --version Displays the version number and exits.

Advanced options

  • --json-console When enabled, JSON objects will be sent to stdout to provide information about tests. This is used by the junit bridge.

  • --heartbeats Delay (in ms) for heartbeats messages sent when --json-console is enabled. Use 0 to disable them.

  • --task-timeout Maximum duration (in ms) for a test task, defaults to 5 minutes.

Configuration file options

Any option configurable through the configuration file can also be specified from the command line with the --config prefix. For example, to configure resources, it is possible to use:

attester --config.resources./ path1/root1 --config.resources./ path2/root2 --config.resources./aria path/to/aria

which is equivalent to run attester with the following configuration file

    "resources": {
        "/": ["path1/root1", "path2/root2"],
        "aria": ["path/to/aria"]

Environment Variables

It is possible to build a special portion of the configuration object from an external file using --env option.

attester --env package.json

This puts the content of package.json inside the env section of attester configuration. It is then possible to reference such values with simple templates.

<%= prop.subprop %> Expands to the value of prop.subprop in the config. Such templates can only be used inside string values, either in arrays or objects

  "resources": {
    "/": "src"
  "tests": {
    "mocha": {
      "files": {
        "includes": ["spec/**/*"]
  "coverage": {
    "files": {
      "rootDirectory": "src",
      "includes": ["**/*.js"]
  "coverage-reports": {
    "json-file": "/reports/coverage-<%= env.version %>.json"

The configuration above generates a coverage report file called coverage-x.y.z.json where x.y.z is the value taken from package.json or any other file passed referenced by --env.

Template options can be used both in yaml and json file and the environment file can be of any of the two format.