diff --git a/lib/index.js b/lib/index.js
index a6eb8cc..adec4fe 100644
--- a/lib/index.js
+++ b/lib/index.js
@@ -119,8 +119,9 @@ function AssertDiff() {
 AssertDiff.options = {strict: false};
 
 Object.keys(assert_plus__WEBPACK_IMPORTED_MODULE_0__).forEach(function(k) {
-  AssertDiff[k] = function() {
-    assert_plus__WEBPACK_IMPORTED_MODULE_0__[k].apply(assert_plus__WEBPACK_IMPORTED_MODULE_0__[k], arguments);
+  let fun = assert_plus__WEBPACK_IMPORTED_MODULE_0__[k];
+  AssertDiff[k] = async function() {
+    return fun.apply(fun, arguments);
   };
 });
 
diff --git a/lib/index.js.map b/lib/index.js.map
index 2a8a433..35c0dea 100644
--- a/lib/index.js.map
+++ b/lib/index.js.map
@@ -1 +1 @@
-{"version":3,"file":"index.js","sources":["webpack:///webpack/universalModuleDefinition","webpack:///webpack/bootstrap","webpack:///./lib/index.mjs","webpack:///external \"assert-plus\"","webpack:///external \"json-diff\""],"sourcesContent":["(function webpackUniversalModuleDefinition(root, factory) {\n\tif(typeof exports === 'object' && typeof module === 'object')\n\t\tmodule.exports = factory();\n\telse if(typeof define === 'function' && define.amd)\n\t\tdefine([], factory);\n\telse {\n\t\tvar a = factory();\n\t\tfor(var i in a) (typeof exports === 'object' ? exports : root)[i] = a[i];\n\t}\n})(global, function() {\nreturn "," \t// The module cache\n \tvar installedModules = {};\n\n \t// The require function\n \tfunction __webpack_require__(moduleId) {\n\n \t\t// Check if module is in cache\n \t\tif(installedModules[moduleId]) {\n \t\t\treturn installedModules[moduleId].exports;\n \t\t}\n \t\t// Create a new module (and put it into the cache)\n \t\tvar module = installedModules[moduleId] = {\n \t\t\ti: moduleId,\n \t\t\tl: false,\n \t\t\texports: {}\n \t\t};\n\n \t\t// Execute the module function\n \t\tmodules[moduleId].call(module.exports, module, module.exports, __webpack_require__);\n\n \t\t// Flag the module as loaded\n \t\tmodule.l = true;\n\n \t\t// Return the exports of the module\n \t\treturn module.exports;\n \t}\n\n\n \t// expose the modules object (__webpack_modules__)\n \t__webpack_require__.m = modules;\n\n \t// expose the module cache\n \t__webpack_require__.c = installedModules;\n\n \t// define getter function for harmony exports\n \t__webpack_require__.d = function(exports, name, getter) {\n \t\tif(!__webpack_require__.o(exports, name)) {\n \t\t\tObject.defineProperty(exports, name, { enumerable: true, get: getter });\n \t\t}\n \t};\n\n \t// define __esModule on exports\n \t__webpack_require__.r = function(exports) {\n \t\tif(typeof Symbol !== 'undefined' && Symbol.toStringTag) {\n \t\t\tObject.defineProperty(exports, Symbol.toStringTag, { value: 'Module' });\n \t\t}\n \t\tObject.defineProperty(exports, '__esModule', { value: true });\n \t};\n\n \t// create a fake namespace object\n \t// mode & 1: value is a module id, require it\n \t// mode & 2: merge all properties of value into the ns\n \t// mode & 4: return value when already ns object\n \t// mode & 8|1: behave like require\n \t__webpack_require__.t = function(value, mode) {\n \t\tif(mode & 1) value = __webpack_require__(value);\n \t\tif(mode & 8) return value;\n \t\tif((mode & 4) && typeof value === 'object' && value && value.__esModule) return value;\n \t\tvar ns = Object.create(null);\n \t\t__webpack_require__.r(ns);\n \t\tObject.defineProperty(ns, 'default', { enumerable: true, value: value });\n \t\tif(mode & 2 && typeof value != 'string') for(var key in value) __webpack_require__.d(ns, key, function(key) { return value[key]; }.bind(null, key));\n \t\treturn ns;\n \t};\n\n \t// getDefaultExport function for compatibility with non-harmony modules\n \t__webpack_require__.n = function(module) {\n \t\tvar getter = module && module.__esModule ?\n \t\t\tfunction getDefault() { return module['default']; } :\n \t\t\tfunction getModuleExports() { return module; };\n \t\t__webpack_require__.d(getter, 'a', getter);\n \t\treturn getter;\n \t};\n\n \t// Object.prototype.hasOwnProperty.call\n \t__webpack_require__.o = function(object, property) { return Object.prototype.hasOwnProperty.call(object, property); };\n\n \t// __webpack_public_path__\n \t__webpack_require__.p = \"\";\n\n\n \t// Load entry module and return exports\n \treturn __webpack_require__(__webpack_require__.s = \"./lib/index.mjs\");\n","import assert from 'assert-plus';\nimport jdiff from 'json-diff';\n\nfunction AssertDiff() {\n  assert.ok.apply(assert.ok, arguments);\n}\n\nAssertDiff.options = {strict: false};\n\nObject.keys(assert).forEach(function(k) {\n  AssertDiff[k] = function() {\n    assert[k].apply(assert[k], arguments);\n  };\n});\n\nexport const deepStrictEqual = AssertDiff.deepStrictEqual = function deepStrictEqual() {\n  try {\n    assert.deepStrictEqual.apply(assert.deepStrictEqual, arguments);\n  } catch (e) {\n    throw new assert.AssertionError({\n      message: addDiffToMessage(e.message, jdiff.diffString(e.expected, e.actual)),\n      stackStartFunction: assert.AssertionError\n    })\n  }\n};\n\nexport const deepEqual = AssertDiff.deepEqual = function deepEqual() {\n  try {\n    assert.deepEqual.apply(assert.deepEqual, arguments);\n  } catch (e) {\n    throw new assert.AssertionError({\n      message: addDiffToMessage(e.message, jdiff.diffString(e.expected, e.actual)),\n      stackStartFunction: assert.AssertionError\n    })\n  }\n  if (AssertDiff.options.strict && jdiff.diff(arguments[0], arguments[1])) {\n    throw new assert.AssertionError({\n      message: addDiffToMessage(arguments[2], jdiff.diffString(arguments[0], arguments[1])),\n      stackStartFunction: assert.AssertionError\n    })\n  }\n};\n\nfunction addDiffToMessage(message, diff) {\n  var msg = message ? message : '';\n  var resetCliColorAttributes = '\\u001b[m';\n\n  return msg + resetCliColorAttributes + '\\n' + diff;\n}\n\nAssertDiff.deepEqualOrig = assert.deepEqual;\n\nexport default AssertDiff;\n","module.exports = require(\"assert-plus\");","module.exports = require(\"json-diff\");"],"mappings":"AAAA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;ACVA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;;;;;;;;;;;;;AClFA;AAAA;AAAA;AAAA;AAAA;AAAA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;;;;;;;;;;;;ACpDA;;;;;;;;;;;ACAA;;;;;A","sourceRoot":""}
\ No newline at end of file
+{"version":3,"file":"index.js","sources":["webpack:///webpack/universalModuleDefinition","webpack:///webpack/bootstrap","webpack:///./lib/index.mjs","webpack:///external \"assert-plus\"","webpack:///external \"json-diff\""],"sourcesContent":["(function webpackUniversalModuleDefinition(root, factory) {\n\tif(typeof exports === 'object' && typeof module === 'object')\n\t\tmodule.exports = factory();\n\telse if(typeof define === 'function' && define.amd)\n\t\tdefine([], factory);\n\telse {\n\t\tvar a = factory();\n\t\tfor(var i in a) (typeof exports === 'object' ? exports : root)[i] = a[i];\n\t}\n})(global, function() {\nreturn "," \t// The module cache\n \tvar installedModules = {};\n\n \t// The require function\n \tfunction __webpack_require__(moduleId) {\n\n \t\t// Check if module is in cache\n \t\tif(installedModules[moduleId]) {\n \t\t\treturn installedModules[moduleId].exports;\n \t\t}\n \t\t// Create a new module (and put it into the cache)\n \t\tvar module = installedModules[moduleId] = {\n \t\t\ti: moduleId,\n \t\t\tl: false,\n \t\t\texports: {}\n \t\t};\n\n \t\t// Execute the module function\n \t\tmodules[moduleId].call(module.exports, module, module.exports, __webpack_require__);\n\n \t\t// Flag the module as loaded\n \t\tmodule.l = true;\n\n \t\t// Return the exports of the module\n \t\treturn module.exports;\n \t}\n\n\n \t// expose the modules object (__webpack_modules__)\n \t__webpack_require__.m = modules;\n\n \t// expose the module cache\n \t__webpack_require__.c = installedModules;\n\n \t// define getter function for harmony exports\n \t__webpack_require__.d = function(exports, name, getter) {\n \t\tif(!__webpack_require__.o(exports, name)) {\n \t\t\tObject.defineProperty(exports, name, { enumerable: true, get: getter });\n \t\t}\n \t};\n\n \t// define __esModule on exports\n \t__webpack_require__.r = function(exports) {\n \t\tif(typeof Symbol !== 'undefined' && Symbol.toStringTag) {\n \t\t\tObject.defineProperty(exports, Symbol.toStringTag, { value: 'Module' });\n \t\t}\n \t\tObject.defineProperty(exports, '__esModule', { value: true });\n \t};\n\n \t// create a fake namespace object\n \t// mode & 1: value is a module id, require it\n \t// mode & 2: merge all properties of value into the ns\n \t// mode & 4: return value when already ns object\n \t// mode & 8|1: behave like require\n \t__webpack_require__.t = function(value, mode) {\n \t\tif(mode & 1) value = __webpack_require__(value);\n \t\tif(mode & 8) return value;\n \t\tif((mode & 4) && typeof value === 'object' && value && value.__esModule) return value;\n \t\tvar ns = Object.create(null);\n \t\t__webpack_require__.r(ns);\n \t\tObject.defineProperty(ns, 'default', { enumerable: true, value: value });\n \t\tif(mode & 2 && typeof value != 'string') for(var key in value) __webpack_require__.d(ns, key, function(key) { return value[key]; }.bind(null, key));\n \t\treturn ns;\n \t};\n\n \t// getDefaultExport function for compatibility with non-harmony modules\n \t__webpack_require__.n = function(module) {\n \t\tvar getter = module && module.__esModule ?\n \t\t\tfunction getDefault() { return module['default']; } :\n \t\t\tfunction getModuleExports() { return module; };\n \t\t__webpack_require__.d(getter, 'a', getter);\n \t\treturn getter;\n \t};\n\n \t// Object.prototype.hasOwnProperty.call\n \t__webpack_require__.o = function(object, property) { return Object.prototype.hasOwnProperty.call(object, property); };\n\n \t// __webpack_public_path__\n \t__webpack_require__.p = \"\";\n\n\n \t// Load entry module and return exports\n \treturn __webpack_require__(__webpack_require__.s = \"./lib/index.mjs\");\n","import assert from 'assert-plus';\nimport jdiff from 'json-diff';\n\nfunction AssertDiff() {\n  assert.ok.apply(assert.ok, arguments);\n}\n\nAssertDiff.options = {strict: false};\n\nObject.keys(assert).forEach(function(k) {\n  let fun = assert[k];\n  AssertDiff[k] = async function() {\n    return fun.apply(fun, arguments);\n  };\n});\n\nexport const deepStrictEqual = AssertDiff.deepStrictEqual = function deepStrictEqual() {\n  try {\n    assert.deepStrictEqual.apply(assert.deepStrictEqual, arguments);\n  } catch (e) {\n    throw new assert.AssertionError({\n      message: addDiffToMessage(e.message, jdiff.diffString(e.expected, e.actual)),\n      stackStartFunction: assert.AssertionError\n    })\n  }\n};\n\nexport const deepEqual = AssertDiff.deepEqual = function deepEqual() {\n  try {\n    assert.deepEqual.apply(assert.deepEqual, arguments);\n  } catch (e) {\n    throw new assert.AssertionError({\n      message: addDiffToMessage(e.message, jdiff.diffString(e.expected, e.actual)),\n      stackStartFunction: assert.AssertionError\n    })\n  }\n  if (AssertDiff.options.strict && jdiff.diff(arguments[0], arguments[1])) {\n    throw new assert.AssertionError({\n      message: addDiffToMessage(arguments[2], jdiff.diffString(arguments[0], arguments[1])),\n      stackStartFunction: assert.AssertionError\n    })\n  }\n};\n\nfunction addDiffToMessage(message, diff) {\n  var msg = message ? message : '';\n  var resetCliColorAttributes = '\\u001b[m';\n\n  return msg + resetCliColorAttributes + '\\n' + diff;\n}\n\nAssertDiff.deepEqualOrig = assert.deepEqual;\n\nexport default AssertDiff;\n","module.exports = require(\"assert-plus\");","module.exports = require(\"json-diff\");"],"mappings":"AAAA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;ACVA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;;;;;;;;;;;;;AClFA;AAAA;AAAA;AAAA;AAAA;AAAA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;AACA;;;;;;;;;;;;ACrDA;;;;;;;;;;;ACAA;;;;;A","sourceRoot":""}
\ No newline at end of file
diff --git a/lib/index.mjs b/lib/index.mjs
index 14d128a..28c7465 100644
--- a/lib/index.mjs
+++ b/lib/index.mjs
@@ -8,8 +8,9 @@ function AssertDiff() {
 AssertDiff.options = {strict: false};
 
 Object.keys(assert).forEach(function(k) {
-  AssertDiff[k] = function() {
-    assert[k].apply(assert[k], arguments);
+  let fun = assert[k];
+  AssertDiff[k] = async function() {
+    return fun.apply(fun, arguments);
   };
 });
 
diff --git a/test/example-passing-tests.js b/test/example-passing-tests.js
index f32db20..d5552e9 100644
--- a/test/example-passing-tests.js
+++ b/test/example-passing-tests.js
@@ -38,3 +38,36 @@ it('basic derived asserts works', function() {
   assert.equal(3, 3, 'this should not fail')
   assert.object({}, 'this should not fail');
 })
+
+it('async functions', async function() {
+  let a = false;
+  await assert.doesNotReject(function() {
+    return new Promise(function(resolve, reject) {
+      setTimeout(function() {
+        a = true;
+        resolve();
+      })
+    })
+  })
+  assert.ok(a);
+
+  let b = false;
+  await assert.rejects(async function() {
+    return new Promise(function(resolve, reject) {
+      setTimeout(function() {
+        b = true;
+        reject(Error('bad error'))
+      })
+    })
+  });
+  assert.ok(b);
+
+  let c = false;
+  await assert.rejects(new Promise(function(resolve, reject) {
+    setTimeout(function() {
+      c = true;
+      reject(Error('bad error'))
+    })
+  }))
+  assert.ok(c);
+})