Breaking: t.end requires test be declared async

Accessing `t.end` now throws an error unless the test is first
declared async via `test.async([title], fn)`

Reference:
  #244

(cherry picked from commit 28b1641)
  Initial implementation of #244 - require explicit test.async

Author: jamestalmage

lib/runner.js

@@ -33,7 +33,8 @@ function Runner(opts) {
 		type: 'test',
 		serial: false,
 		exclusive: false,
-		skipped: false
+		skipped: false,
+		async: false
 	}, this._addFn.bind(this));
 }
 
@@ -47,7 +48,8 @@ var chainableFunctions = {
 	skip: {skipped: true},
 	only: {exclusive: true},
 	beforeEach: {type: 'beforeEach'},
-	afterEach: {type: 'afterEach'}
+	afterEach: {type: 'afterEach'},
+	async: {async: true}
 };
 
 function makeChain(defaults, parentAdd) {

lib/test.js

@@ -28,6 +28,11 @@ function Test(title, fn) {
 	this.duration = null;
 	this.assertError = undefined;
 
+	// TODO(jamestalmage): make this an optional constructor arg instead of having Runner set it after the fact.
+	// metadata should just always exist, otherwise it requires a bunch of ugly checks all over the place.
+	// I will fix this correctly in the upstream PR.
+	this.metadata = {};
+
 	// store the time point before test execution
 	// to calculate the total time spent in test
 	this._timeStart = null;
@@ -47,7 +52,9 @@ module.exports = Test;
 Test.prototype._assert = function () {
 	this.assertCount++;
 
-	if (this.assertCount === this.planCount) {
+	// TODO(jamestalmage): no only auto-ends in "declared" async mode `test.async(...)`. Should we drop auto-end behavior all together?
+	// https://github.com/sindresorhus/ava/issues/244#issuecomment-158705839
+	if (this.metadata.async && this.assertCount === this.planCount) {
 		globals.setImmediate(this.exit.bind(this));
 	}
 };
@@ -135,27 +142,38 @@ Test.prototype.run = function () {
 	ret = observableToPromise(ret);
 
 	if (isPromise(ret)) {
-		ret
-			.then(function () {
-				if (!self.planCount || self.planCount === self.assertCount) {
-					self.exit();
-				}
-			})
-			.catch(function (err) {
-				self._setAssertError(new assert.AssertionError({
-					actual: err,
-					message: 'Promise rejected → ' + err,
-					operator: 'promise'
-				}));
-
+		if (!this.metadata.async) {
+			ret = ret.then(function () {
 				self.exit();
 			});
+		}
+
+		ret.catch(function (err) {
+			self._setAssertError(new assert.AssertionError({
+				actual: err,
+				message: 'Promise rejected → ' + err,
+				operator: 'promise'
+			}));
+
+			self.exit();
+		});
+	} else if (!this.metadata.async) {
+		this.exit();
 	}
 
 	return this.promise.promise;
 };
 
-Test.prototype.end = function (err) {
+Object.defineProperty(Test.prototype, 'end', {
+	get: function () {
+		if (this.metadata.async) {
+			return this._end;
+		}
+		throw new Error('t.end is not supported in this context. To use t.end as a callback, you must explicitly declare the test asynchronous via `test.async(testName, fn)` ');
+	}
+});
+
+Test.prototype._end = function (err) {
 	if (err) {
 		this._setAssertError(new assert.AssertionError({
 			actual: err,

test/fixture/circular-reference-on-assertion.js

@@ -4,5 +4,4 @@ test(t => {
 	var circular = ['a', 'b'];
 	circular.push(circular);
 	t.same([circular, 'c'], [circular, 'd']);
-	t.end();
 });

test/fixture/es2015.js

@@ -2,5 +2,4 @@ import test from '../../';
 
 test(t => {
 	t.pass();
-	t.end();
 });

test/fixture/fail-fast.js

@@ -2,10 +2,8 @@ import test from '../../';
 
 test(t => {
 	t.fail();
-	t.end();
 });
 
 test(t => {
 	t.pass();
-	t.end();
 });

test/fixture/hooks-failing.js

@@ -4,10 +4,8 @@ test.beforeEach(fail);
 test(pass);
 
 function pass(t) {
-	t.end();
 }
 
 function fail(t) {
 	t.fail();
-	t.end();
 }

test/fixture/hooks-passing.js

@@ -7,5 +7,4 @@ test.afterEach(pass);
 test(pass);
 
 function pass(t) {
-	t.end();
 }

test/fixture/long-running.js

@@ -2,7 +2,7 @@
 const test = require('../../');
 var onExit = require('signal-exit');
 
-test('long running', function (t) {
+test.async('long running', function (t) {
 	t.plan(1);
 
 	onExit(function () {

test/fixture/loud-rejection.js

@@ -1,6 +1,6 @@
 const test = require('../../');
 
-test('creates an unhandled rejection', t => {
+test.async('creates an unhandled rejection', t => {
 	Promise.reject(new Error(`You can't handle this!`));
 
 	setTimeout(function () {

test/fixture/one-pass-one-fail.js

@@ -2,10 +2,8 @@ const test = require('../../');
 
 test('this is a passing test', t => {
 	t.ok(true);
-	t.end();
 });
 
 test('this is a failing test', t => {
 	t.ok(false);
-	t.end();
 });