assert: async parameter for assert.throws() and assert.doesNotThrow()

lib/assert.js

@@ -243,21 +243,21 @@ function expectedException(actual, expected, msg) {
   return expected.call({}, actual) === true;
 }
 
-function getActual(block) {
+async function getActual(block) {
   if (typeof block !== 'function') {
     throw new errors.TypeError('ERR_INVALID_ARG_TYPE', 'block', 'Function',
                                block);
   }
   try {
-    block();
+    await block();
   } catch (e) {
     return e;
   }
 }
 
 // Expected to throw an error.
-assert.throws = function throws(block, error, message) {
-  const actual = getActual(block);
+assert.throws = async function throws(block, error, message) {
+  const actual = await getActual(block);
 
   if (typeof error === 'string') {
     if (arguments.length === 3)
@@ -289,8 +289,8 @@ assert.throws = function throws(block, error, message) {
   }
 };
 
-assert.doesNotThrow = function doesNotThrow(block, error, message) {
-  const actual = getActual(block);
+assert.doesNotThrow = async function doesNotThrow(block, error, message) {
+  const actual = await getActual(block);
   if (actual === undefined)
     return;
 

test/parallel/test-assert-async.js

@@ -0,0 +1,42 @@
+'use strict';
+const common = require('../common');
+const assert = require('assert');
+const promisify = require('util').promisify;
+const wait = promisify(setTimeout);
+
+// Ensure async support for assert.throws() and assert.doesNotThrow()
+/* eslint-disable prefer-common-expectserror */
+
+assert.throws(
+  async () => { assert.fail(); },
+  common.expectsError({
+    code: 'ERR_ASSERTION',
+    type: assert.AssertionError,
+    message: 'Failed',
+    operator: undefined,
+    actual: undefined,
+    expected: undefined
+  })
+);
+
+assert.throws(
+  async () => {
+    await wait(common.platformTimeout(10));
+    assert.fail();
+  },
+  common.expectsError({
+    code: 'ERR_ASSERTION',
+    type: assert.AssertionError,
+    message: 'Failed',
+    operator: undefined,
+    actual: undefined,
+    expected: undefined
+  })
+);
+
+assert.doesNotThrow(async () => {});
+
+assert.doesNotThrow(async () => {
+  await wait(common.platformTimeout(10));
+  assert.fail();
+});