We're celebrating the new year with the official AVA 4 release!
npm install -D ava
The cool new stuff
By default, test files are now run in worker threads! Huge thanks to @dnlup for landing this.
Test files should run a little quicker, since it's easier to spin up a worker thread than a child process. You can use
--no-worker-threads on the command line, or
workerThreads: false in your AVA configuration, to fall back to using child processes.
Shared workers are no longer experimental
Shared workers are no longer experimental. This is a powerful feature that loads a program in a worker thread in AVA's main process and then communicate with code running in the test workers. This enables your tests to better utilize shared resources during a test run, as well as providing opportunities to set up these resources before tests start (or clean them up after).
When you use watch mode, shared workers remain loaded across runs.
Improved test selection
AVA selects test files based on your
ava.config.* configuration files. When used on the CLI you can then provide patterns to select a subset of these files.
If AVA finds files based on the configuration, but none of those were selected to the CLI arguments, it now prints a warning.
Better monorepo support
AVA now looks for
ava.config.* files in parent directories, until it finds a directory with a
.git directory (or file). This lets you specify AVA configuration at the top of your monorepo and still run AVA from within each package.
New snapshot format
@ninevra has worked tirelessly on landing a new snapshot format. It contains all information necessary to regenerate the report file. This allows for snapshots to be updated even if tests or assertions are skipped.
Previously failing test files run first
AVA now records which test files failed in the previous run. It then prioritizes testing these files when you run AVA again. Thanks @bunysae!
AVA 4 comes with full ES module support. Both ESM and CJS entrypoints are provided so that you can use it no matter how you manage your project.
ava.config.js file is now treated as CJS or ESM depending on module type configured in the
ava.config.mjs is now supported.
Note that dependency tracking in watch mode does not yet work with ES modules.
Dedicated macro factory with type inference
test.macro() returns an object that can be used with
test() and hooks. The
t.context type is inherited from
test. When used with TypeScript this gives much better type inference.
Like with AVA 3, regular functions that also have a
title property that is a string-returning function are supported. However the type checking won’t be as good.
AVA now uses the source map support that’s built in to Node.js itself. This should give better stack traces. However we’re not sure yet what happens if you load a program that automatically modifies stack traces.
Line number selection (where
npx ava test.js:5 runs the test at line 5) now uses source maps and so should work better with TypeScript files.
Assertions as type guards
Most assertions now return a boolean indicating whether they passed. If you use AVA with TypeScript, you can use this as a type guard. Thanks @jmarkham828!
(This is not supported for
t.snapshot() and the "throws" assertions.)
AVA 4 requires at least Node.js 12.22, 14.17, 16.4 or 17. Node.js 10 is no longer supported.
If installed globally, AVA will no longer use any locally installed version. Install locally and run with
npx ava instead. When running test files from another project that also has AVA installed, those test files will now fail to run (because they'll try and use that other AVA version).
- Support for
@ava/babelhas been removed. We haven’t seen enough contributions to that package to recommend it for AVA 4. We’d be open to reinstating it in the future (just as we’d be open to support any other compilation provider).
- As a consequence, “enhanced assertions” are no longer available.
- AVA 4 requires
- Support for the
esmpackage has been removed.
ava.config.jsnow follows the module type configured in
ava.config.*files may be found that are outside your project directory.
Tests and assertions
- By default test files execute in worker threads, not child processes.
test.meta.snapshotDirectoryare now file URL strings.
- Whitespace in test titles is now normalized. This could result in two tests being treated as having the same title, even though they are different in code. Thanks @KillyMXI!
t.try()no longer take an array of test implementations. Use a loop instead.
t.throwAsync()assertions can no longer be called with a
nullvalue for the expectations argument.
t.end()have been removed. Use async functions and
t.teardown()now executes in last-in-first-out order.
- Snapshots recorded using earlier AVA versions are no longer recognized. Run
npx ava -uto rebuild your snapshots after upgrading.
- Snapshots no longer recognize React elements, instead we want to provide this functionality through a plugin interface
t.snapshot()no longer works in hooks.
t.snapshot()no longer takes an options argument allowing you to customize the snapshot ID.
t.throwsAsync()assertions must now be an
- You’re expected to use
test.macro()when declaring macros.
- Implementation arguments now default to
- Types have been renamed.
MetaInterface, other types with
Interfacesuffixes now use the
Fnsuffix. There may be some other changes too. 4b4b2f6
undefinedwhen the assertion fails. The type definition now matches this behavior.
- Our TypeScript definitions are now tested against TypeScript 4.4
- We’ve removed the non-verbose reporter because it proved too hard to maintain two subtly different reporter outputs. We’d really like to rewrite the reporter.
- AVA's configuration files may now export promises or asynchronous factory methods.
--configargument may now point to a file that is not alongside the
- When you use
t.timeout(), AVA itself won’t time out until your test does. Thanks @OhYash!
- Multi-line snapshot labels now render correctly in Markdown. Thanks @KillyMXI!
- The reporters now clean up
.specextensions from file names, as well as
- Watch mode is better at detecting changes to snapshots and not rerunning tests.
- @Fem-Fem made their first contribution in #2750
- @OhYash made their first contribution in #2758
- @KillyMXI made their first contribution in #2773
- @mcecode made their first contribution in #2794
- @duncanfinney made their first contribution in #2820
- @asaid-0 made their first contribution in #2788
- @bompus made their first contribution in #2843
- @StefanoA1 made their first contribution in #2849
- @live627 made their first contribution in #2851
- @alessandroasm made their first contribution in #2863
- @eltociear made their first contribution in #2870
- @hamidbae made their first contribution in #2878
- @rrichardson made their first contribution in #2910
- @make-github-pseudonymous-again made their first contribution in #2913
- @lightmare made their first contribution in #2918