Adds support for ava.config.js files

docs/recipes/babel.md

@@ -10,7 +10,7 @@ If you are using Babel for your source files then you must also [configure sourc
 
 ## Customize how AVA compiles your test files
 
-You can override the default Babel configuration AVA uses for test file compilation in `package.json`. For example, the configuration below adds support for JSX syntax and stage 3 features:
+You can override the default Babel configuration AVA uses for test file compilation in `package.json` or `ava.config.js`. For example, the configuration below adds support for JSX syntax and stage 3 features:
 
 ```json
 {

docs/recipes/es-modules.md

@@ -12,7 +12,7 @@ First, install [`esm`](https://github.com/standard-things/esm):
 $ npm install esm
 ```
 
-Configure it in your `package.json` file, and add it to AVA's `"require"` option as well. Make sure to add it as the first item:
+Configure it in your `package.json` or `ava.config.js` file, and add it to AVA's `"require"` option as well. Make sure to add it as the first item:
 
 ```json
 {

docs/recipes/flow.md

@@ -6,7 +6,7 @@ AVA comes bundled with a Flow definition file. This allows developers to leverag
 
 This guide assumes you've already set up Flow for your project. Note that AVA's definition as been tested with version 0.69.0.
 
-We recommend you use AVA's built-in Babel pipeline to strip Flow type annotations and declarations. AVA automatically applies your project's Babel configuration, so everything may just work without changes. Alternatively install [`@babel/plugin-transform-flow-strip-types`](https://www.npmjs.com/package/@babel/plugin-transform-flow-strip-types) and customize AVA's configuration in the `package.json` file as follows:
+We recommend you use AVA's built-in Babel pipeline to strip Flow type annotations and declarations. AVA automatically applies your project's Babel configuration, so everything may just work without changes. Alternatively install [`@babel/plugin-transform-flow-strip-types`](https://www.npmjs.com/package/@babel/plugin-transform-flow-strip-types) and customize AVA's configuration in the `package.json` file (or the `ava.config.js` file) as follows:
 
 ```json
 {

docs/recipes/jspm-systemjs.md

@@ -31,7 +31,7 @@ You will need to install the [AVA JSPM loader](https://github.com/skorlir/ava-js
 ```
 $ npm install --save-dev ava-jspm-loader @babel/register
 ```
-You will also need to update your AVA config in package.json to use the JSPM loader.
+You will also need to update your AVA config in the `package.json` or `ava.config.js` to use the JSPM loader.
 
 ```json
 {

docs/recipes/react.md

@@ -6,7 +6,7 @@ Translations: [Español](https://github.com/avajs/ava-docs/blob/master/es_ES/doc
 
 AVA automatically extends your regular (project-level) Babel configuration. You should be able to use React in your test files without any additional configuration.
 
-However if you want to set it up explicitly, add the preset to the test options in AVA's Babel pipeline by modifying your `package.json`:
+However if you want to set it up explicitly, add the preset to the test options in AVA's Babel pipeline by modifying your `package.json` or `ava.config.js` file:
 
 ```json
 {

docs/recipes/watch-mode.md

@@ -45,7 +45,7 @@ And then use:
 $ npm run watch:test
 ```
 
-Finally you could configure AVA to *always* run in watch mode by setting the `watch` key in the [`ava` section of your `package.json`]:
+Finally you could configure AVA to *always* run in watch mode by setting the `watch` key in the [`ava` section of your `package.json`, or `ava.config.js` file][config]:
 
 ```json
 {
@@ -67,7 +67,7 @@ In AVA there's a distinction between *source files* and *test files*. As you can
 
 By default AVA watches for changes to the test files, snapshot files, `package.json`, and any other `.js` files. It'll ignore files in [certain directories](https://github.com/novemberborn/ignore-by-default/blob/master/index.js) as provided by the [`ignore-by-default`] package.
 
-You can configure patterns for the source files in the [`ava` section of your `package.json`] file, using the `source` key.
+You can configure patterns for the source files in the [`ava` section of your `package.json`, or `ava.config.js` file][config], using the `source` key.
 
 You can specify patterns to match files in the folders that would otherwise be ignored, e.g. use `node_modules/some-dependency/*.js` to specify all `.js` files in `node_modules/some-dependency` as a source, even though normally all files in `node_modules` are ignored. Note that you need to specify an exact directory; `{bower_components,node_modules}/**/*.js` won't work.
 
@@ -77,7 +77,7 @@ If your tests write to disk they may trigger the watcher to rerun your tests. Co
 
 AVA tracks which source files your test files depend on. If you change such a dependency only the test file that depends on it will be rerun. AVA will rerun all tests if it cannot determine which test file depends on the changed source file.
 
-Dependency tracking works for required modules. Custom extensions and transpilers are supported, provided you [added them in your `package.json`], and not from inside your test file. Files accessed using the `fs` module are not tracked.
+Dependency tracking works for required modules. Custom extensions and transpilers are supported, provided you [added them in your `package.json` or `ava.config.js` file][config], and not from inside your test file. Files accessed using the `fs` module are not tracked.
 
 ## Watch mode and the `.only` modifier
 
@@ -118,5 +118,4 @@ Watch mode is relatively new and there might be some rough edges. Please [report
 [Install Troubleshooting]: https://github.com/paulmillr/chokidar#install-troubleshooting
 [`ignore-by-default`]: https://github.com/novemberborn/ignore-by-default
 [`.only` modifier]: https://github.com/avajs/ava#running-specific-tests
-[`ava` section of your `package.json`]: https://github.com/avajs/ava#configuration
-[added them in your `package.json`]: https://github.com/avajs/ava#configuration
+[config]: https://github.com/avajs/ava#configuration

lib/cli.js

@@ -6,8 +6,8 @@ const figures = require('figures');
 const arrify = require('arrify');
 const meow = require('meow');
 const Promise = require('bluebird');
-const pkgConf = require('pkg-conf');
 const isCi = require('is-ci');
+const loadConf = require('./load-config');
 
 // Bluebird specific
 Promise.longStackTraces();
@@ -18,10 +18,13 @@ function exit(message) {
 }
 
 exports.run = () => { // eslint-disable-line complexity
-	const conf = pkgConf.sync('ava');
-
-	const filepath = pkgConf.filepath(conf);
-	const projectDir = filepath === null ? process.cwd() : path.dirname(filepath);
+	let conf = {};
+	let confError = null;
+	try {
+		conf = loadConf();
+	} catch (err) {
+		confError = err;
+	}
 
 	const cli = meow(`
 		Usage
@@ -110,6 +113,15 @@ exports.run = () => { // eslint-disable-line complexity
 	updateNotifier({pkg: cli.pkg}).notify();
 	const chalk = require('./chalk').set({enabled: cli.flags.color});
 
+	if (confError) {
+		if (confError.parent) {
+			exit(`${confError.message}\n\n${chalk.gray((confError.parent && confError.parent.stack) || confError.parent)}`);
+		} else {
+			exit(confError.message);
+		}
+	}
+
+	const {projectDir} = conf;
 	if (cli.flags.resetCache) {
 		const cacheDir = path.join(projectDir, 'node_modules', '.cache', 'ava');
 		del('*', {

lib/load-config.js

@@ -0,0 +1,58 @@
+'use strict';
+const path = require('path');
+const esm = require('esm');
+const isPlainObject = require('is-plain-object');
+const pkgConf = require('pkg-conf');
+
+const NO_SUCH_FILE = Symbol('no ava.config.js file');
+const MISSING_DEFAULT_EXPORT = Symbol('missing default export');
+
+function loadConfig(defaults = {}) {
+	const packageConf = pkgConf.sync('ava');
+	const filepath = pkgConf.filepath(packageConf);
+	const projectDir = filepath === null ? process.cwd() : path.dirname(filepath);
+
+	let fileConf;
+	try {
+		({default: fileConf = MISSING_DEFAULT_EXPORT} = esm(module, {
+			cjs: false,
+			mode: 'all'
+		})(path.join(projectDir, 'ava.config.js')));
+	} catch (err) {
+		if (err && err.code === 'MODULE_NOT_FOUND') {
+			fileConf = NO_SUCH_FILE;
+		} else {
+			throw Object.assign(new Error('Error loading ava.config.js'), {parent: err});
+		}
+	}
+
+	if (fileConf === MISSING_DEFAULT_EXPORT) {
+		throw new Error('ava.config.js must have a default export, using ES module syntax');
+	}
+
+	if (fileConf !== NO_SUCH_FILE) {
+		if (Object.keys(packageConf).length > 0) {
+			throw new Error('Conflicting configuration in ava.config.js and package.json');
+		}
+
+		if (fileConf && typeof fileConf.then === 'function') {
+			throw new TypeError('ava.config.js must not export a promise');
+		}
+		if (!isPlainObject(fileConf) && typeof fileConf !== 'function') {
+			throw new TypeError('ava.config.js must export a plain object or factory function');
+		}
+
+		if (typeof fileConf === 'function') {
+			fileConf = fileConf({projectDir});
+			if (fileConf && typeof fileConf.then === 'function') {
+				throw new TypeError('Factory method exported by ava.config.js must not return a promise');
+			}
+			if (!isPlainObject(fileConf)) {
+				throw new TypeError('Factory method exported by ava.config.js must return a plain object');
+			}
+		}
+	}
+
+	return Object.assign({}, defaults, fileConf, packageConf, {projectDir});
+}
+module.exports = loadConfig;

package.json

@@ -91,6 +91,7 @@
 		"emittery": "^0.3.0",
 		"empower-core": "^0.6.1",
 		"equal-length": "^1.0.0",
+		"esm": "^3.0.15",
 		"escape-string-regexp": "^1.0.5",
 		"figures": "^2.0.0",
 		"get-port": "^3.2.0",
@@ -143,7 +144,6 @@
 		"codecov": "^3.0.0",
 		"del": "^3.0.0",
 		"delay": "^2.0.0",
-		"esm": "^3.0.15",
 		"execa": "^0.10.0",
 		"flow-bin": "^0.69.0",
 		"get-stream": "^3.0.0",

profile.js

@@ -8,13 +8,13 @@ require('./lib/worker/load-chalk'); // eslint-disable-line import/no-unassigned-
 const path = require('path');
 const meow = require('meow');
 const Promise = require('bluebird');
-const pkgConf = require('pkg-conf');
 const uniqueTempDir = require('unique-temp-dir');
 const arrify = require('arrify');
 const resolveCwd = require('resolve-cwd');
 const babelPipeline = require('./lib/babel-pipeline');
 const RunStatus = require('./lib/run-status');
 const VerboseReporter = require('./lib/reporters/verbose');
+const loadConfig = require('./lib/load-config');
 
 function resolveModules(modules) {
 	return arrify(modules).map(name => {
@@ -30,18 +30,14 @@ function resolveModules(modules) {
 
 Promise.longStackTraces();
 
-const conf = pkgConf.sync('ava', {
-	defaults: {
-		babel: {
-			testOptions: {}
-		},
-		compileEnhancements: true
-	}
+const conf = loadConfig({
+	babel: {
+		testOptions: {}
+	},
+	compileEnhancements: true
 });
 
-const filepath = pkgConf.filepath(conf);
-const projectDir = filepath === null ? process.cwd() : path.dirname(filepath);
-
+const {projectDir} = conf;
 // Define a minimal set of options from the main CLI
 const cli = meow(`
 	Usage

readme.md

@@ -232,7 +232,7 @@ AVA automatically removes unrelated lines in stack traces, allowing you to find
 
 ## Configuration
 
-All of the CLI options can be configured in the `ava` section of your `package.json`. This allows you to modify the default behavior of the `ava` command, so you don't have to repeatedly type the same options on the command prompt.
+All of the CLI options can be configured in the `ava` section of either your `package.json` or an `ava.config.js` file. This allows you to modify the default behavior of the `ava` command, so you don't have to repeatedly type the same options on the command prompt.
 
 To ignore a file or directory, prefix the pattern with an `!` (exclamation mark).
 
@@ -291,6 +291,47 @@ Arguments passed to the CLI will always take precedence over the configuration i
 
 Note that providing files on the CLI overrides the `files` option. If you've configured a glob pattern, for instance `test/**/*.test.js`, you may want to repeat it when using the CLI: `ava 'test/integration/*.test.js'`.
 
+### Using `ava.config.js`
+
+To use an `ava.config.js` file:
+
+ 1. It must be in the same directory as your `package.json`
+ 2. Your `package.json` must not contain an `ava` property (or, if it does, it must be an empty object)
+
+The config file must have a default export, using ES modules. It can either be a plain object or a factory function which returns a plain object:
+
+```js
+export default {
+	require: ['esm']
+};
+```
+
+```js
+export default function factory() {
+	return {
+		require: ['esm']
+	};
+};
+```
+
+The factory function is called with an object containing a `projectDir` property, which you could use to change the returned configuration:
+
+```js
+export default ({projectDir}) => {
+	if (projectDir === '/Users/username/projects/my-project') {
+		return {
+			// Config A
+		};
+	}
+
+	return {
+		// Config B
+	};
+};
+```
+
+Note that the final configuration must not be a promise.
+
 ## Documentation
 
 Tests are run concurrently. You can specify synchronous and asynchronous tests. Tests are considered synchronous unless you return a promise or [observable](https://github.com/zenparsing/zen-observable).

test/cli.js

@@ -121,6 +121,20 @@ for (const [where, which, msg = '\'js\', \'jsx\''] of [
 	});
 }
 
+test('formats errors from ava.config.js', t => {
+	execCli(['es2015.js'], {dirname: 'fixture/load-config/throws'}, (err, stdout, stderr) => {
+		t.ok(err);
+
+		const lines = stderr.split('\n');
+		t.is(lines[0], '');
+		t.is(lines[1], figures.cross + ' Error loading ava.config.js');
+		t.is(lines[2], '');
+		t.match(lines[3], /ava\.config\.js/);
+		t.match(lines[4], /foo/);
+		t.end();
+	});
+});
+
 test('enabling long stack traces will provide detailed debug information', t => {
 	execCli('fixture/long-stack-trace', (err, stdout, stderr) => {
 		t.ok(err);

test/fixture/load-config/factory-no-plain-return/ava.config.js

@@ -0,0 +1,3 @@
+class Config {}
+
+export default () => new Config();

test/fixture/load-config/factory-no-plain-return/package.json

@@ -0,0 +1 @@
+{}

test/fixture/load-config/factory-no-promise-return/ava.config.js

@@ -0,0 +1,5 @@
+export default () => new Promise(resolve => {
+	resolve({
+		files: 'this-should-not-work'
+	});
+});

test/fixture/load-config/factory-no-promise-return/package.json

@@ -0,0 +1 @@
+{}

test/fixture/load-config/no-default-export/ava.config.js

@@ -0,0 +1 @@
+export const config = {}; // eslint-disable-line import/prefer-default-export

test/fixture/load-config/no-default-export/package.json

@@ -0,0 +1 @@
+{}

test/fixture/load-config/no-plain-config/ava.config.js

@@ -0,0 +1 @@
+export default 'should not work!';

test/fixture/load-config/no-plain-config/package.json

@@ -0,0 +1 @@
+{}

test/fixture/load-config/no-promise-config/ava.config.js

@@ -0,0 +1 @@
+export default Promise.resolve('should not work!');

test/fixture/load-config/no-promise-config/package.json

@@ -0,0 +1 @@
+{}

test/fixture/load-config/package-no-file-yes-factory/ava.config.js

@@ -0,0 +1,5 @@
+export default ({projectDir}) => {
+	return {
+		files: projectDir
+	};
+};

test/fixture/load-config/package-no-file-yes-factory/package.json

@@ -0,0 +1 @@
+{}

test/fixture/load-config/package-no-file-yes/ava.config.js

@@ -0,0 +1,5 @@
+const config = {
+	files: 'config-file-esm-test-value'
+};
+
+export default config;

test/fixture/load-config/package-no-file-yes/package.json

@@ -0,0 +1 @@
+{}

test/fixture/load-config/package-only/package.json

@@ -0,0 +1,6 @@
+{
+	"ava": {
+		"failFast": true,
+		"concurrency": 10
+	}
+}

test/fixture/load-config/package-yes-file-yes/ava.config.js

@@ -0,0 +1,3 @@
+export default {
+	files: 'package-yes-files-yes-test-value'
+};

test/fixture/load-config/package-yes-file-yes/package.json

@@ -0,0 +1,8 @@
+{
+	"ava": {
+		"files": [
+			"abc",
+			"!xyz"
+		]
+	}
+}

test/fixture/load-config/throws/ava.config.js

@@ -0,0 +1 @@
+throw new Error('foo');

test/fixture/load-config/throws/package.json

@@ -0,0 +1 @@
+{}