Allow worker CLI flags to be specified

This removes AVA's internal flags, set by fork.js and consumed by
test-worker.js. Fixes #1393.

AVA now forwards arguments, provided after an `--` argument terminator,
to the worker process. Arguments are available from `process.argv[2]`
onwards.

docs/recipes/passing-arguments-to-your-test-files.md

@@ -0,0 +1,30 @@
+# Passing arguments to your test files
+
+You can pass command line arguments to your test files. Use the `--` argument terminator to separate AVA's arguments from your own:
+
+```js
+// test.js
+import test from 'ava';
+
+test('argv', t => {
+	t.deepEqual(process.argv.slice(2), ['--hello', 'world']);
+});
+```
+
+```console
+$ npx ava -- --hello world
+```
+
+You need two `--` argument terminators if you're invoking AVA through an `npm test` script:
+
+```json
+{
+	"scripts": {
+		"test": "ava"
+	}
+}
+```
+
+```console
+$ npm test -- -- --hello world
+```

lib/cli.js

@@ -107,6 +107,9 @@ exports.run = () => {
 			color: {
 				type: 'boolean',
 				default: 'color' in conf ? conf.color : require('supports-color').stdout !== false
+			},
+			'--': {
+				type: 'string'
 			}
 		}
 	});
@@ -156,7 +159,8 @@ exports.run = () => {
 		concurrency: conf.concurrency ? parseInt(conf.concurrency, 10) : 0,
 		updateSnapshots: conf.updateSnapshots,
 		snapshotDir: conf.snapshotDir ? path.resolve(projectDir, conf.snapshotDir) : null,
-		color: conf.color
+		color: conf.color,
+		workerArgv: cli.flags['--']
 	});
 
 	let reporter;

lib/fork.js

@@ -34,7 +34,7 @@ module.exports = (file, opts, execArgv) => {
 		} : false
 	}, opts);
 
-	const args = [JSON.stringify(opts), opts.color ? '--color' : '--no-color'];
+	const args = [JSON.stringify(opts), opts.color ? '--color' : '--no-color'].concat(opts.workerArgv);
 
 	const ps = childProcess.fork(path.join(__dirname, 'test-worker.js'), args, {
 		cwd: opts.projectDir,

lib/process-adapter.js

@@ -39,6 +39,9 @@ exports.forceRefChannel = () => {
 const opts = JSON.parse(process.argv[2]);
 require('./worker-options').set(opts);
 
+// Remove arguments received from fork.js and leave those specified by the user.
+process.argv.splice(2, 2);
+
 // Fake TTY support
 if (opts.tty) {
 	process.stdout.isTTY = true;

lib/test-worker.js

@@ -3,7 +3,7 @@
 // Check if the test is being run without AVA cli
 {
 	const path = require('path');
-	const chalk = require('chalk');
+	const chalk = require('chalk'); // This processes the --color/--no-color argument passed by fork.js
 
 	const isForked = typeof process.send === 'function';
 	if (!isForked) {

readme.md

@@ -1161,6 +1161,7 @@ It's the [Andromeda galaxy](https://simple.wikipedia.org/wiki/Andromeda_galaxy).
 - [Flow](docs/recipes/flow.md)
 - [Configuring Babel][Babel recipe]
 - [Using ES modules](docs/recipes/es-modules.md)
+- [Passing arguments to your test files](docs/recipes/passing-arguments-to-your-test-files.md)
 - [Testing React components](docs/recipes/react.md)
 - [Testing Vue.js components](docs/recipes/vue.md)
 - [JSPM and SystemJS](docs/recipes/jspm-systemjs.md)

test/cli.js

@@ -210,27 +210,6 @@ test('precompiler require hook does not apply to source files', t => {
 	});
 });
 
-test('pkg-conf: defaults', t => {
-	execCli([], {dirname: 'fixture/pkg-conf/defaults'}, err => {
-		t.ifError(err);
-		t.end();
-	});
-});
-
-test('pkg-conf: pkg-overrides', t => {
-	execCli([], {dirname: 'fixture/pkg-conf/pkg-overrides'}, err => {
-		t.ifError(err);
-		t.end();
-	});
-});
-
-test('pkg-conf: cli takes precedence', t => {
-	execCli(['--match=foo*', '--no-serial', '--cache', '--no-fail-fast', 'c.js'], {dirname: 'fixture/pkg-conf/precedence'}, err => {
-		t.ifError(err);
-		t.end();
-	});
-});
-
 test('pkg-conf(resolve-dir): works as expected when run from the package.json directory', t => {
 	execCli(['--verbose'], {dirname: 'fixture/pkg-conf/resolve-dir'}, (err, stdout, stderr) => {
 		t.ifError(err);
@@ -863,3 +842,10 @@ test('workers load compiled helpers if in the require configuration', t => {
 		t.end();
 	});
 });
+
+test('additional arguments are forwarded to the worker', t => {
+	execCli(['worker-argv.js', '--serial', '--', '--hello', 'world'], {dirname: 'fixture'}, err => {
+		t.ifError(err);
+		t.end();
+	});
+});

test/fixture/worker-argv.js

@@ -0,0 +1,5 @@
+import test from '../../';
+
+test('argv', t => {
+	t.deepEqual(process.argv, [process.execPath, require.resolve('../../lib/test-worker.js'), '--hello', 'world']);
+});