gruntMock

A simple mock for testing Grunt multi-tasks.

Overview

Some Grunt tasks are thin wrappers over functionality that's already well tested (ex: grunt-contrib-jshint). Other Grunt tasks offer custom functionality, specialized behavior, or need their output to be verified. gruntMock is targeted at the second set and offers a way to validate the complete, end-to-end lifecycle of a Grunt multi-task.

gruntMock is simple mock object that simulates the Grunt task runner for multi-tasks and can easily be integrated into a unit testing environment such as Nodeunit. gruntMock invokes tasks the same way Grunt does and exposes (almost) the same set of APIs. After providing input to a task, gruntMock runs and captures its output so tests can verify expected behavior. Task success and failure are unified, so it's easy to write positive and negative tests.

Example

var gruntMock = require('gruntmock');
var example = require('./example-task.js');
 
exports.exampleTest = {
 
  pass: function(test) {
    test.expect(4);
    var mock = gruntMock.create({
      target: 'pass',
      files: [
        { src: ['unused.txt'] }
      ],
      options: { str: 'string', num: 1 }
    });
    mock.invoke(example, function(err) {
      test.ok(!err);
      test.equal(mock.logOk.length, 1);
      test.equal(mock.logOk[0], 'pass');
      test.equal(mock.logError.length, 0);
      test.done();
    });
  },
 
  fail: function(test) {
    test.expect(2);
    var mock = gruntMock.create({ target: 'fail' });
    mock.invoke(example, function(err) {
      test.ok(err);
      test.equal(err.message, 'fail');
      test.done();
    });
  }
};

Mocking

Some of Grunt's APIs are self-contained and don't need special handling (ex: grunt.file), so gruntMock exposes the original implementation via a pass-through. Other APIs need to be captured or redirected for test purposes (ex: grunt.log), so gruntMock returns a custom implementation. Other APIs are complicated or uncommon enough that gruntMock doesn't try to support them (ex: grunt.task).

Interface

/**
 * Creates an instance of GruntMock.
 *
 * @param {Object} config Configuration object (target, files, options, data).
 * @return {GruntMock} A new instance of GruntMock.
 */
var gruntMock = GruntMock.create(config)
 
/**
 * Mocks Grunt and invokes a multi-task.
 *
 * @param {Function} task A Grunt multi-task.
 * @param {Function} callback A callback(err, mock) function.
 */
gruntMock.invoke(task, callback)
 
/**
 * Array of all error messages a task logs.
 */
gruntMock.logError
 
/**
 * Array of all non-error messages a task logs.
 */
gruntMock.logOk

Supported APIs

grunt

• registerMultiTask
• warn
• fatal
• option
• package
• version

grunt.event

• All methods (via pass-through)

grunt.fail

• All methods

grunt.file

• All methods (via pass-through)

grunt.log

• All methods (with helpers via pass-through)

grunt.option

• All methods (via pass-through)

grunt.task

• registerMultiTask

grunt.template

• All methods (via pass-through)

grunt.util

• All methods (via pass-through)

Inside Tasks

• args (see note below)
• async
• data
• errorCount
• files (see note below)
• filesSrc
• flags (see note below)
• name
• nameArgs
• options
• target

Notes

• gruntMock supports both synchronous and asynchronous task execution. gruntMock's invoke method always calls its callback asynchronously.
• The files input uses Grunt's array format. Globbing is not handled by gruntMock because it's outside the scope of testing a Grunt task. Test input can be provided un-globbed for the same effect.
• Although grunt.log.warn behaves like grunt.log.error, it does not increment this.errorCount, so its output is logged to gruntMock.logOk.
• gruntMock unconditionally captures and reports verbose/debug output along with normal log output. Differentiating among normal/verbose/debug output is not currently supported.
• Grunt's --force option is not supported; a call to grunt.warn.fatal or an unhandled exception always ends the task.
• this.args and this.flags are unused and always empty.

License

MIT

Releases

• 0.1.0 - Initial release.
• 0.1.1 - Lower-case package name per npm policy.
• 0.2.0 - Add support for this.data inside a task.
• 0.2.1 - Update to work with Grunt 1.0.0 release.