babel-plugin-espower

babel-plugin-espower

Babel plugin for power-assert.

DESCRIPTION

babel-plugin-espower is a Babel plugin for power-assert.

power-assert provides descriptive assertion messages for your tests, like this.

  1) ES6 demo Destructuring and TemplateLiteral:

      AssertionError:   # test/demo_test.js:7

  assert(`${ alice.name } and ${ bob.name }` === `bob and alice`)
         |   |     |             |   |       |   |
         |   |     |             |   |       |   "bob and alice"
         |   |     |             |   "bob"   false
         |   |     "alice"       Object{name:"bob"}
         |   Object{name:"alice"}
         "alice and bob"

  --- [string] `bob and alice`
  +++ [string] `${ alice.name } and ${ bob.name }`
  @@ -1,13 +1,13 @@
  -bob and alice
  +alice and bob

Pull-requests, issue reports and patches are always welcomed. See power-assert project for more documentation.

INSTALL

$ npm install --save-dev babel-plugin-espower

CAUTION

Babel6 is incompatible with Babel5. For Babel 5 or lower, you need to use the 1.x release of babel-plugin-espower.

$ npm install --save-dev babel-plugin-espower@1.1.0

HOW TO USE

via .babelrc

{
  "presets": [
    ...
  ],
  "plugins": [
    "babel-plugin-espower"
  ]
}

$ babel /path/to/test/some_test.js > /path/to/build/some_test.js

For example, with babel-register module and .babelrc above, you can run mocha without code generation steps.

$ $(npm bin)/mocha --require babel-register test/some_test.js

via Babel API

var babel = require('babel-core');
var jsCode = fs.readFileSync('/path/to/test/some_test.js');
var transformed = babel.transform(jsCode, {
    presets: [...],
    plugins: ['babel-plugin-espower']
});
console.log(transformed.code);

via Babel Require Hook

require('babel-register')({
    presets: [...],
    plugins: ['babel-plugin-espower']
});

For example, with babel_hook.js above, you can run mocha without code generation steps.

$ $(npm bin)/mocha --require ./babel_hook /path/to/test/demo_test.js

with babelify

var fs = require('fs');
var browserify = require('browserify');
var babelify = require('babelify');
var glob = require('glob'),
browserify({ entries: glob.sync('./test/*_test.js'), debug: true })
  .transform(babelify.configure({
      presets: [...],
      plugins: ['babel-plugin-espower']
  }))
  .bundle()
  .on('error', function (err) { console.log('Error : ' + err.message); })
  .pipe(fs.createWriteStream('all_test.js'));

$ $(npm bin)/browserify -d -e ./test/*_test.js -t [ babelify --presets ... --plugins babel-plugin-espower ]

with babelify and gulp

var source = require('vinyl-source-stream');
var browserify = require('browserify');
var glob = require('glob'),
gulp.task('build_test', function() {
    var files = glob.sync('./test/*_test.js');
    var b = browserify({entries: files, debug: true});
    b.transform(babelify.configure({
        presets: [...],
        plugins: ['babel-plugin-espower']
    }));
    return b.bundle()
        .pipe(source('all_test.js'))
        .pipe(gulp.dest('./build'));
});

with babelify and Karma

module.exports = function(config) {
  config.set({
    frameworks: ['mocha', 'browserify'],
    files: [
      "test/**/*.js"
    ],
    preprocessors: {
      "test/**/*.js": "browserify"
    },
    browserify: {
      debug: true,
      transform: [
        [
          'babelify', {
            presets: [...],
            plugins: ['babel-plugin-espower']
          }
        ]
      ]
    },
    // ...

EXAMPLE

For given test file test/demo_test.js below,

import assert from 'power-assert';

describe('ES6 demo', () => {

    it('Destructuring and TemplateLiteral', () => {
        let [alice, bob] = [ { name: 'alice' }, { name: 'bob' } ];
        assert(`${alice.name} and ${bob.name}` === `bob and alice`);
    });

    it('ArrowFunctionExpression and SpreadElement', () => {
        let seven = 7, ary = [4, 5];
        assert(seven === ((v, i) => v + i)(...[...ary]));
    });

    it('Enhanced Object Literals', () => {
        let name = 'bobby';
        assert.deepEqual({
            name,
            [ `${name}'s greet` ]: `Hello, I'm ${name}`
        }, null);
    });

});

prepare babel_hook.js to transform tests.

{
  "presets": [
    ...
  ],
  "plugins": [
    "babel-plugin-espower"
  ]
}

Run mocha with --require babel-register option. You will see the power-assert output appears.

$ $(npm bin)/mocha --require babel-register test/demo_test.js

  ES6 demo
    1) Destructuring and TemplateLiteral
    2) ArrowFunctionExpression and SpreadElement
    3) Enhanced Object Literals


  0 passing
  3 failing

  1) ES6 demo Destructuring and TemplateLiteral:

      AssertionError:   # test/demo_test.js:7

  assert(`${ alice.name } and ${ bob.name }` === `bob and alice`)
         |   |     |             |   |       |   |
         |   |     |             |   |       |   "bob and alice"
         |   |     |             |   "bob"   false
         |   |     "alice"       Object{name:"bob"}
         |   Object{name:"alice"}
         "alice and bob"

  --- [string] `bob and alice`
  +++ [string] `${ alice.name } and ${ bob.name }`
  @@ -1,13 +1,13 @@
  -bob and alice
  +alice and bob

      at Context.<anonymous> (test/demo_test.js:19:28)

  2) ES6 demo ArrowFunctionExpression and SpreadElement:

      AssertionError:   # test/demo_test.js:12

  assert(seven === ((v, i) => v + i)(...[...ary]))
         |     |   |                    |   |
         |     |   |                    |   [4,5]
         |     |   9                    [4,5]
         7     false

  [number] ((v, i) => v + i)(...[...ary])
  => 9
  [number] seven
  => 7

      at Context.<anonymous> (test/demo_test.js:29:28)

  3) ES6 demo Enhanced Object Literals:
     AssertionError:   # test/demo_test.js:17

  assert.deepEqual({name,[`${ name }'s greet`]: `Hello, I'm ${ name }`}, null)
                   |      |   |                 |              |
                   |      |   |                 |              "bobby"
                   |      |   "bobby"           "Hello, I'm bobby"
                   |      "bobby's greet"
                   Object{name:"bobby","bobby's greet":"Hello, I'm bobby"}

      at Context.<anonymous> (test/demo_test.js:40:29)

CUSTOMIZE

var plugin = createEspowerPlugin(babel, [options])

You can customize assertion patterns via Babel API,

var babel = require('babel-core');
var createEspowerPlugin = require('babel-plugin-espower/create');
var jsCode = fs.readFileSync('/path/to/test/some_test.js');
var transformed = babel.transform(jsCode, {
    presets: [...],
    plugins: [
        createEspowerPlugin(babel, {
            patterns: [
                'assert.isNull(object, [message])',
                'assert.same(actual, expected, [message])',
                'assert.near(actual, expected, delta, [message])'
            ]
        })
    ]
});
console.log(transformed.code);

or via Require Hook.

var createEspowerPlugin = require('babel-plugin-espower/create');
require('babel-register')({
    presets: [...],
    plugins: [
        createEspowerPlugin(babel, {
            patterns: [
                'assert.isNull(object, [message])',
                'assert.same(actual, expected, [message])',
                'assert.near(actual, expected, delta, [message])'
            ]
        })
    ]
});

options

type	default value
object	objects shown below

Configuration options for babel-plugin-espower. If not passed, default options will be used (return value of defaultOptions() with default visitorKeys, astWhiteList, path, sourceRoot and sourceMap. visitorKeys is value of babel.types.VISITOR_KEYS. astWhiteList is value of babel.types.BUILDER_KEYS. path is filename passed to babel. sourceRoot is be return value of process.cwd(), sourceMap is babel's internal SourceMap object).

{
    patterns: [
        'assert(value, [message])',
        'assert.ok(value, [message])',
        'assert.equal(actual, expected, [message])',
        'assert.notEqual(actual, expected, [message])',
        'assert.strictEqual(actual, expected, [message])',
        'assert.notStrictEqual(actual, expected, [message])',
        'assert.deepEqual(actual, expected, [message])',
        'assert.notDeepEqual(actual, expected, [message])',
        'assert.deepStrictEqual(actual, expected, [message])',
        'assert.notDeepStrictEqual(actual, expected, [message])'
    ],
    visitorKeys: babel.types.VISITOR_KEYS,
    astWhiteList: babel.types.BUILDER_KEYS,
    sourceRoot: process.cwd(),
    path: file.opts.filename,
    sourceMap: file.opts.inputSourceMap
}

CHANGELOG

See CHANGELOG

AUTHOR

• Takuto Wada

CONTRIBUTORS

• James Talmage (jamestalmage)

LICENSE

Licensed under the MIT license.

Changelog

2.1.1 (2016-01-26)

Performance Improvements

• Use prototype based Recorder for performance boost (by @jamestalmage)