karma-stacktrace

karma-stacktrace

What

Provides readable mapped stacktrace for failed tests to debug the them in your browser.

Motivation

Test frameworks like QUnit and Jasmine use non-standard stack property of Error object to output a stacktrace for failed unit tests. Modern browsers do not apply sourcemaps to Error.prototype.stack and unmapped stacktrace looks useless.

An example of an unmapped stacktrace:

The framework catches failed tests and reports mapped stacktrace by using stacktrace-js library:

Install

Install with yarn:

yarn add karma-stacktrace

With npm:

npm install karma-stacktrace

Karma configuration

Add stacktrace to the list of frameworks for a corresponding karma configuration:

// karma.conf.js
module.exports = function(config) {
  config.set({
    //...
    frameworks: ['stacktrace'],
    //...
  });
};

To avoid blocking the main execution thread of a web application Web Workers are used by default for parsing/mapping stacktrace, however you can disable it (you might need it for inline sourcemaps):

// karma.conf.js
module.exports = function(config) {
  config.set({
    //...
    client: {
      stacktrace: {
        useWorker: false
      }
    },
    //...
  });
};

Limitations/Gotchas

• At the moment the framework supports only Jasmine and QUnit testing frameworks.
• The framework attaches isolated reporters to trace mapped stacktrace, it does not affect stacktrace in original messages.
• It is recommended to set useWorker option to false value for inline sourcemaps to get mapped stacktrace.

Examples

See examples folder for details.

Inspired by

• sourcemapped-stacktrace