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We're proud to introduce AVA 3! 馃殌

When we began AVA, JavaScript was very different. Most syntax you find familiar today was not supported by Node.js. Instead we relied on Babel to support that syntax before it made its way to Node.js itself.

These days most new stage-4 syntax is adopted quickly. It's often not necessary to transpile anything. Therefore we're removing our built-in Babel support from AVA itself.

Without Babel you'll have to resort to using require() functions in your JavaScript files. But, you say, Node.js 13 supports ECMAScript Modules!

Well, we're getting there. For a start, AVA now also looks for .cjs files. And .mjs files are recognized too, but can't be loaded just yet. This also impacts ava.config.js files. If you'd like to help out delivering full .mjs support check out the issues in the ESM support project.

Removing Babel allowed us to simplify how test files are selected. Likely non-test files, inside "fixture" or "helper" directories are ignored. The same for files that are inside an underscore-prefixed directory. We've made some other breaking changes in this area so please do read the full release notes.

You can again pass glob patterns on the CLI. However these now filter the test files that AVA already selected based on the configuration. In other words you can't run files that wouldn't be run by invoking npx ava.

AVA now interrupts your tests if there's no progress for 10 seconds. Use the timeout configuration or --timeout CLI option to change this.

New features

Built-in debug mode

You can now debug individual test files using the V8 Inspector:

npx ava debug test.js

Connect to the debugger with Chrome DevTools. Or set up a debugger in VSCode.

Configurable Node.js arguments

You can now configure the arguments passed to Node.js itself when AVA starts its worker processes. Use the nodeArguments configuration or combine with the --node-arguments CLI option.

All breaking changes

Supported Node.js versions

We now support Node.js 10, 12 and 13. The minimal versions are 10.18.0, 12.14.0 and 13.5.0 respectively.

Removing Babel

Utilize Babel with AVA by installing our @ava/babel package and then enabling Babel by setting babel: true in the AVA configuration. Having this as a separate package means it can evolve independently.

The compileEnhancements setting has been moved into the babel configuration. Consequently, the t.assert() assertion will only print its detailed information when you use Babel. And we won't be able to catch typical mistakes with t.throws() as well as we could before.

The ava/stage-4 preset is now available from @ava/babel/stage-4. Our old @ava/babel-preset-transform-test-files and @ava/babel-preset-stage-4 packages are no longer maintained and not installed with AVA itself.

ECMAScript Module Support

AVA now also looks for .cjs and .mjs test files. That said, .mjs files cannot be loaded just yet.

Also, when you add "type": "module" , AVA would really like to treat .js files as ECMAScript Modules, but can't just yet.

Similarly,ava.config.cjs configuration files are now supported. ava.config.mjs files not just yet.

With AVA 2, we loaded ava.config.js files using the esm package. To avoid confusion between the different module formats we now only support export default statements. No import, no __filename. Configuration files that have dependencies should be written as a .cjs file for now.

Configuration files can only have .cjs, .js and .mjs extensions.

The remaining work is tracked in the ESM support project.

File selection

When you use the default configuration AVA will no longer select files matching the following glob patterns:

  • **/__tests__/**/__helper__/**/*
  • **/__tests__/**/__helpers__/**/*
  • **/__tests__/**/__fixture__/**/*
  • **/__tests__/**/__fixtures__/**/*
  • **/test/**/helper/**/*
  • **/test/**/helpers/**/*
  • **/test/**/fixture/**/*
  • **/test/**/fixtures/**/*
  • **/tests/**/helper/**/*
  • **/tests/**/helpers/**/*
  • **/tests/**/fixture/**/*
  • **/tests/**/fixtures/**/*

Additionally, when a file has a parent directory that starts with a single underscore, it can never be a test file.

test.js files are only selected if they're next to the package.json file, or inside top-level src and source directories.

We've removed the configuration of helpers. Previously, files selected by the helpers glob patterns were never considered test files. Now that this configuration is no longer supported you'll need to ensure the files patterns exclude your helper files. If you're using Babel, you can configure the compilation of additional files .

The sources configuration has also been removed. Instead, use the ignoredByWatcher configuration. Changes to files matched by these glob patterns will not cause the watcher to rerun tests.

Negated sources patterns must be used without the negation in ignoredByWatcher:

 export default {
-  sources: ['!examples/**/*']
+  ignoredByWatcher: ['examples/**/*']

CLI changes

Internally we've replaced meow by yargs. We're not expecting things to break because of this, but you never know.

Resetting the cache

The --reset-cache argument has been replaced by a proper reset-cache command:

npx ava reset-cache

File selection (again!)

AVA again accepts glob patterns via the CLI:

npx ava '**/api/**/*'

The way this work is that AVA first finds all test files, according to the configuration, and then filters to select just the files that also match the glob patterns passed via the CLI.

You can still pass paths to specific files:

npx ava src/api/test/my-api-test.js

However unlike with AVA 2, you can no longer specify test files that aren't already selected by AVA's configuration.

t.throws() and t.throwsAsync() assertions

The second argument passed to these assertions must now be an expectation object. You can no longer pass the expected constructor, error message or regular expression.

Other breaking changes

  • Support for old esm versions has been removed.
  • We've set a default test timeout of 10 seconds. This means that if no test results are received for 10 seconds, AVA forces its worker processes to quit.
  • The NODE_PATH environment variable is no longer rewritten to ensure values are absolute paths.
  • AVA longer fakes the TTY in worker processes.

Other changes

  • We've simplified how we identify observables. Any object returned by a test implementation that has a subscribe function is assumed to be an observable. AVA's type definition has been updated accordingly.
  • The TAP reporter now reports hook failures as test failures.
  • We've added an example of module path mapping to our TypeScript recipe.
  • We've added a Selenium WebDriver JS recipe.

All changes



Thank you @tymfear, @HeathNaylor, @grnch, @alexdrans, @MoppetX, @jimmywarting, @micaelmbagira, @aptester, @theashraf, @sramam and @maximelkin. We couldn't have done this without you!