EVENT_SUITE_ADD_* events (@beatfactor)browser-entry.js (@PaperStrike)XUNIT and JSON reporter crash in parallel mode (@curtisman)--fail-zero (@juergba)--node-option (@juergba)JSON reporter (@dorny)#4702: Error rethrow from cwd-relative path while loading .mocharc.js (@kirill-golovan)
#4688: Usage of custom interface in parallel mode (@juergba)
#4687: ESM: don't swallow MODULE_NOT_FOUND errors in case of type:module (@giltayar)
We added a separate browser bundle mocha-es2018.js in javascript ES2018, as we skipped the transpilation down to ES5. This is an experimental step towards freezing Mocha's support of IE11.
hasStableEsmImplementation (@alexander-fenster)Mocha is going ESM-first! This means that it will now use ESM import(test_file) to load the test files, instead of the CommonJS require(test_file). This is not a problem, as import can also load most files that require does. In the rare cases where this fails, it will fallback to require(...). This ESM-first approach is the next step in Mocha's ESM migration, and allows ESM loaders to load and transform the test file.
#4638: Limit the size of actual/expected for diff generation (@juergba)
#4389: Refactoring: Consuming log-symbols alternate to code for win32 in reporters/base (@MoonSupport)
Runner(suite: Suite, delay: boolean) signature (@juergba)options.require to Mocha constructor for root hook plugins on parallel runs (@juergba)top-level await and ESM test files (@juergba)Also thanks to @outsideris for various improvements on our GH actions workflows.
require interface (@alexander-fenster)EvalError caused by regenerator-runtime (@snoack)import from mocha in parallel mode (@nicojs)require error when bundling Mocha with Webpack (@devhazem)Also thanks to @outsideris and @HyunSangHan for various fixes to our website and documentation.
Fixed stuff.
Promise rejections and erroneous “done() called twice” errors (@boneskull)MaxListenersExceededWarning in watch mode (@boneskull)Also thanks to @akeating for a documentation fix!
The major feature added in v8.2.0 is addition of support for global fixtures.
While Mocha has always had the ability to run setup and teardown via a hook (e.g., a before() at the top level of a test file) when running tests in serial, Mocha v8.0.0 added support for parallel runs. Parallel runs are incompatible with this strategy; e.g., a top-level before() would only run for the file in which it was defined.
With global fixtures, Mocha can now perform user-defined setup and teardown regardless of mode, and these fixtures are guaranteed to run once and only once. This holds for parallel mode, serial mode, and even “watch” mode (the teardown will run once you hit Ctrl-C, just before Mocha finally exits). Tasks such as starting and stopping servers are well-suited to global fixtures, but not sharing resources--global fixtures do not share context with your test files (but they do share context with each other).
Here's a short example of usage:
// fixtures.js // can be async or not exports.mochaGlobalSetup = async function() { this.server = await startSomeServer({port: process.env.TEST_PORT}); console.log(`server running on port ${this.server.port}`); }; exports.mochaGlobalTeardown = async function() { // the context (`this`) is shared, but not with the test files await this.server.stop(); console.log(`server on port ${this.server.port} stopped`); }; // this file can contain root hook plugins as well! // exports.mochaHooks = { ... }
Fixtures are loaded with --require, e.g., mocha --require fixtures.js.
For detailed information, please see the documentation and this handy-dandy flowchart to help understand the differences between hooks, root hook plugins, and global fixtures (and when you should use each).
test.js) now usable with --extension option (@jordanstephens).js, .test.js) now usable with --extension option (@boneskull)json reporter now contains speed (“fast”/“medium”/“slow”) property (@wwhurin)For implementors of custom reporters:
Runner.prototype.workerReporter()); reporters should subclass ParallelBufferedReporter in mocha/lib/nodejs/reporters/parallel-bufferedRunner.prototype.linkPartialObjects()); use if strict object equality is needed when consuming Runner event dataRunner.prototype.isParallelMode())npm v6.x causing some of Mocha‘s deps to be installed when mocha is present in a package’s devDependencies and npm install --production is run the package's working copy (@boneskull)nyc with Mocha in parallel mode (@boneskull)lookupFiles() in mocha/lib/utils, which was broken/missing in Mocha v8.1.0; it now prints a deprecation warning (use const {lookupFiles} = require('mocha/lib/cli') instead) (@boneskull)Thanks to @AviVahl, @donghoon-song, @ValeriaVG, @znarf, @sujin-park, and @majecty for other helpful contributions!
Mocha.utils.lookupFiles() and Webpack compatibility (both broken since v8.1.0); Mocha.utils.lookupFiles() is now deprecated and will be removed in the next major revision of Mocha; use require('mocha/lib/cli').lookupFiles instead (@boneskull)In this release, Mocha now builds its browser bundle with Rollup and Babel, which will provide the project's codebase more flexibility and consistency.
While we‘ve been diligent about backwards compatibility, it’s possible consumers of the browser bundle will encounter differences (other than an increase in the bundle size). If you do encounter an issue with the build, please report it here.
This release does not drop support for IE11.
Other community contributions came from @Devjeel, @Harsha509 and @sharath2106. Thank you to everyone who contributed to this release!
Do you read Korean? See this guide to running parallel tests in Mocha, translated by our maintainer, @outsideris.
mocha init (@boneskull)delay option in browser (@craigtaub)--enable-source-maps with Mocha (@bcoe)The obligatory patch after a major.
--parallel when combined with --watch (@boneskull)In this major release, Mocha adds the ability to run tests in parallel. Better late than never! Please note the breaking changes detailed below.
Let's welcome @giltayar and @nicojs to the maintenance team!
#4164: Mocha v8.0.0 now requires Node.js v10.12.0 or newer. Mocha no longer supports the Node.js v8.x line (“Carbon”), which entered End-of-Life at the end of 2019 (@UlisesGascon)
#4175: Having been deprecated with a warning since v7.0.0, mocha.opts is no longer supported (@juergba)
:sparkles: WORKAROUND: Replace mocha.opts with a configuration file.
#4260: Remove enableTimeout() (this.enableTimeout()) from the context object (@craigtaub)
:sparkles: WORKAROUND: Replace usage of this.enableTimeout(false) in your tests with this.timeout(0).
#4315: The spec option no longer supports a comma-delimited list of files (@juergba)
:sparkles: WORKAROUND: Use an array instead (e.g., "spec": "foo.js,bar.js" becomes "spec": ["foo.js", "bar.js"]).
#4309: Drop support for Node.js v13.x line, which is now End-of-Life (@juergba)
#4282: --forbid-only will throw an error even if exclusive tests are avoided via --grep or other means (@arvidOtt)
#4223: The context object's skip() (this.skip()) in a “before all” (before()) hook will no longer execute subsequent sibling hooks, in addition to hooks in child suites (@juergba)
#4178: Remove previously soft-deprecated APIs (@wnghdcjfe):
Mocha.prototype.ignoreLeaks()Mocha.prototype.useColors()Mocha.prototype.useInlineDiffs()Mocha.prototype.hideDiff()#4245: Add ability to run tests in parallel for Node.js (see docs) (@boneskull)
:exclamation: See also #4244; Root Hook Plugins (docs) -- root hooks must be defined via Root Hook Plugins to work in parallel mode
#4299: In some circumstances, Mocha can run ES modules under Node.js v10 -- use at your own risk! (@giltayar)
(All bug fixes in Mocha v8.0.0 are also breaking changes, and are listed above)
--forbid-only does not recognize it.only when before crashes (@arvidOtt)#4038: Add Node.js native ESM support (@giltayar)
Mocha supports writing your test files as ES modules:
--experimental-modules optionNote: Node.JS native ECMAScript Modules implementation has status: Stability: 1 - Experimental
allowUncaught option (@juergba)package.json (@outsideris)reporterOptions (@holm)--debug/--debug-brk and deprecate debug argument (@juergba)--list-interfaces replaces --interfaces--list-reporters replaces --reportersthis.skip() (@juergba):getOptions() and lib/cli/options.js (@juergba)pending test: don't swallow, but retrospectively fail the test for correct exit code (@juergba)Mocha constructor's option names with command-line options (@juergba)--watch mode with chokidar (@geigerzaehler):--watch-files and --watch-ignore--watch-extensionsThese are soft-deprecated, and will emit a warning upon use. Support will be removed in (likely) the next major version of Mocha:
--inspect-brk/--inspect (@juergba)Mocha constructor: improve browser setup (@juergba)--allow-uncaught with this.skip() (@juergba)done() (@jgehrcke):coffee: with emoji ☕️ (@pzrq)sh to bash for code block in docs/index.md (@HyunSangHan)package.json (@Munter)EVENT_RUN_END events upon uncaught exception (@juergba)html reporter (browser) (@pec9399)--file (@gabegorelick)global or globals (@pascalpp)_mocha binary (@juergba)--timeout/--slow string values and duplicate arguments (@boneskull, @juergba)--watch options (@geigerzaehler)--watch mode behavior (@geigerzaehler)runWatch into separate module (@geigerzaehler)mocha.min.js file to stacktrace filter (@brian-lagerman)--exclude to --ignore and create alias (@boneskull)mocha.css (@DanielRuf)yargs-related global scope pollution (@inukshuk)pnpm (@boneskull)options parameter (@plroebuck).jsonc extension (@sstephant)These are soft-deprecated, and will emit a warning upon use. Support will be removed in (likely) the next major version of Mocha:
this.skip() in “before each” hooks (@juergba)--allow-uncaught for uncaught exceptions thrown inside hooks (@givanse)and some regressions:
Suite cloning by copying root property (@fatso83)Two more regressions fixed:
mocha.opts (@boneskull)--require does not break on module names that look like certain node flags (@boneskull)The obligatory round of post-major-release bugfixes.
These issues were regressions.
test.js when run without arguments (@plroebuck)--ui (@boneskull)--watch (@boneskull)undefined value from a describe callback is no longer considered deprecated (@boneskull)@mocha/docdash@2 (@tendonstrength)require cache (@plroebuck)Suite#_onlyTests and Suite#_onlySuites (@vkarpov15)lookupFiles and files (@plroebuck)--delay (and other boolean options) not working in all cases (@boneskull)--reporter-option/--reporter-options did not support comma-separated key/value pairs (@boneskull)mocharc.json in published package (@boneskull)Documentation for this release can be found at next.mochajs.org!
Welcome @plroebuck, @craigtaub, & @markowsiak to the team!
--grep and --fgrep are now mutually exclusive; attempting to use both will cause Mocha to fail instead of simply ignoring --grep--compilers is no longer supported; attempting to use will cause Mocha to fail with a link to more information-d is no longer an alias for --debug; -d is currently ignored--watch-extensions no longer implies js; it must be explicitly added (@TheDancingCode)tap reporter emits error messages (@chrmod)before hook, subsequent before hooks and tests in nested suites are now skipped (@bannmoore)lib/template.html has moved to lib/browser/template.html (@boneskull)mocha.opts at a user-specified path (@plroebuck)Base-extending reporter without a Runner parameter will throw an exception (@craigtaub)code property (and some will have additional metadata). Some Error messages have changed. Please use the code property to check Error types instead of the message property; these descriptions will be localized in the future. (@craigtaub)These are soft-deprecated, and will emit a warning upon use. Support will be removed in (likely) the next major version of Mocha:
-gc users should use --gc-global insteadbin/options should now use the loadMochaOpts or loadOptions (preferred) functions exported by the lib/cli/options moduleRegarding the Mocha class constructor (from lib/mocha):
color: false instead of useColors: falsetimeout: false instead of enableTimeouts: falseAll of the above deprecations were introduced by #3556.
mocha.opts is now considered “legacy”; please prefer RC file or package.json over mocha.opts.
Enhancements introduced in #3556:
Mocha now supports “RC” files in JS, JSON, YAML, or package.json-based (using mocha property) format
.mocharc.js, .mocharc.json, .mocharc.yaml or .mocharc.yml are valid “rc” file names and will be automatically loaded--config /path/to/rc/file to specify an explicit path--package /path/to/package.json to specify an explicit package.json to read the mocha prop from--no-config or --no-package to completely disable loading of configuration via RC file and package.json, respectivelypackage.jsonmocha.optsNode/V8 flag support in mocha executable:
node flags as supported by the running version of node (also thanks to @demurgos)--v8- to the flag namepackage.json properties, or mocha.opts--inspect) now imply --no-timeouts--debug will automatically invoke --inspect if supported by running version of nodeSupport negation of any Mocha-specific command-line flag by prepending --no- to the flag name
Interfaces now have descriptions when listed using --interfaces flag
Mocha constructor supports all options
--extension is now an alias for --watch-extensions and affects non-watch-mode test runs as well. For example, to run only test/*.coffee (not test/*.js), you can do mocha --require coffee-script/register --extensions coffee.
#3552: tap reporter is now TAP13-capable (@plroebuck & @mollstam)
#3535: Mocha's version can now be queried programmatically via public property Mocha.prototype.version (@plroebuck)
#2529: Runner now emits a retry event when tests are retried (reporters can listen for this) (@catdad)
#2962, #3111: In-browser notification support; warn about missing prereqs when --growl supplied (@plroebuck)
--no-timeouts and --timeout 0 now does what you'd expect (@boneskull)--no-exit option (@boneskull)SIGINT (@boneskull)--forbid-only and --forbid-pending now “fail fast” when encountered on a suite (@outsideris)stdout: prefix in browser console (@Bamieh)utils.isPromise() (@fabiosantoscode)--bail would not execute “after” nor “after each” hooks (@juergba)TERM=dumb (@plroebuck).github/CONTRIBUTING.md (@markowsiak)slow option (@finfin)--watch docs (@benglass)ms userland module instead of hand-rolled solution (@gizemkeser)mocha.opts (@plroebuck)before hooks when using --bail (@outsideris)Buffer.from() (@harrysarson)--watch (@boneskull)Welcome @outsideris to the team!
--bail failing to bail within hooks (@outsideris)describe.skip()) (@outsideris)CHANGELOG.md (@tagoro9, @honzajavorek)This patch features a fix to address a potential “low severity” ReDoS vulnerability in the diff package (a dependency of Mocha).
generateDiff() in Base reporter (@harrysarson)This release fixes a class of tests which report as false positives. Certain tests will now break, though they would have previously been reported as passing. Details below. Sorry for the inconvenience!
#3226: Do not swallow errors that are thrown asynchronously from passing tests (@boneskull). Example:
```js it(‘should actually fail, sorry!’, function (done) { // passing assertion assert(true === true);
// test complete & is marked as passing done();
// ...but something evil lurks within setTimeout(() => { throw new Error(‘chaos!’); }, 100); }); ```
Previously to this version, Mocha would have silently swallowed the chaos! exception, and you wouldn't know. Well, now you know. Mocha cannot recover from this gracefully, so it will exit with a nonzero code.
Maintainers of external reporters: If a test of this class is encountered, the Runner instance will emit the end event twice; you may need to change your reporter to use runner.once('end') intead of runner.on('end').
#3093: Fix stack trace reformatting problem (@outsideris)
browser-stdout to v1.3.1 (@honzajavorek)...your garden-variety patch release.
Special thanks to Wallaby.js for their continued support! :heart:
--delay now works with .only() (@silviom)--glob docs (@outsideris)Mocha starts off 2018 right by again dropping support for unmaintained rubbish.
Welcome @vkarpov15 to the team!
--file command line argument (documentation) (@hswolff)--no-timeouts docs (@dfberry)done() callback docs (@maraisr)README.md organization (@xxczaki)