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@yannickcr
Last active October 28, 2019 13:14
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Testing ES6 React components with Gulp + Mocha + Istanbul

Testing ES6 React components with Gulp + Mocha + Istanbul

Recipe to test your ES6 React components.

$ npm install gulp gulp-util gulp-mocha gulp-istanbul isparta run-sequence babel jsdom

Note: You must name all your files .js, even if they contains JSX, or istanbul will not instrument them.

  • gulp test: Run unit tests
  • gulp test:coverage: Run unit tests with code coverage (the report is stored in ./coverage)
  • gulp tdd: Watch files and run unit tests (without coverage) on changes
'use strict';
var gulp = require('gulp');
var gutil = require('gulp-util');
var mocha = require('gulp-mocha');
var istanbul = require('gulp-istanbul');
var isparta = require('isparta');
var runSequence = require('run-sequence');
// Transform all required files with Babel
require('babel/register');
// Files to process
var TEST_FILES = 'tests/**/*.js';
var SRC_FILES = 'js/**/*.js';
/*
* Instrument files using istanbul and isparta
*/
gulp.task('coverage:instrument', function() {
return gulp.src(SRC_FILES)
.pipe(istanbul({
instrumenter: isparta.Instrumenter // Use the isparta instrumenter (code coverage for ES6)
// Istanbul configuration (see https://github.com/SBoudrias/gulp-istanbul#istanbulopt)
// ...
}))
.pipe(istanbul.hookRequire()); // Force `require` to return covered files
});
/*
* Write coverage reports after test success
*/
gulp.task('coverage:report', function(done) {
return gulp.src(SRC_FILES, {read: false})
.pipe(istanbul.writeReports({
// Istanbul configuration (see https://github.com/SBoudrias/gulp-istanbul#istanbulwritereportsopt)
// ...
}));
});
/**
* Run unit tests
*/
gulp.task('test', function() {
return gulp.src(TEST_FILES, {read: false})
.pipe(mocha({
require: [__dirname + '/lib/jsdom'] // Prepare environement for React/JSX testing
}));
});
/**
* Run unit tests with code coverage
*/
gulp.task('test:coverage', function(done) {
runSequence('coverage:instrument', 'test', 'coverage:report', done);
});
/**
* Watch files and run unit tests on changes
*/
gulp.task('tdd', function(done) {
gulp.watch([
TEST_FILES,
SRC_FILES
], ['test']).on('error', gutil.log);
});
'use strict';
var jsdom = require('jsdom');
/**
* Borrowed from: https://github.com/tmpvar/jsdom/issues/135#issuecomment-68191941
*/
function applyJsdomWorkaround(window) {
Object.defineProperties(window.HTMLElement.prototype, {
offsetLeft: {
get: function() {
return parseFloat(window.getComputedStyle(this).marginLeft) || 0;
}
},
offsetTop: {
get: function() {
return parseFloat(window.getComputedStyle(this).marginTop) || 0;
}
},
offsetHeight: {
get: function() {
return parseFloat(window.getComputedStyle(this).height) || 0;
}
},
offsetWidth: {
get: function() {
return parseFloat(window.getComputedStyle(this).width) || 0;
}
}
});
}
function setupDom() {
var baseMarkup = '<!DOCTYPE html><html><head><title></title></head><body></body></html>';
var window = jsdom.jsdom(baseMarkup).defaultView;
global.window = window;
global.document = window.document;
global.navigator = window.navigator;
applyJsdomWorkaround(window);
}
setupDom();
@rowlandekemezie
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@yannickcr, how do you handle es6 codes before running the test in your gulp test task

@juaniyyoo
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@andela-rekemezie : There is this article that explain it quite clearly.
You just need to set .babelrc and move gulpfile.js to gulpfile.babel.js.

@saladinjake
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just need a .babelrc file and rename gulpfile.js to gulpefile.babel.js

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