diff --git a/yargs/yargs-tests.ts b/yargs/yargs-tests.ts
index c964e1b724..9246bf4725 100644
--- a/yargs/yargs-tests.ts
+++ b/yargs/yargs-tests.ts
@@ -4,8 +4,9 @@
 // Definitions: https://github.com/DefinitelyTyped/DefinitelyTyped
 
 /// <reference path="yargs.d.ts" />
+/// <reference path="../node/node.d.ts"/>
 
-import yargs = require('yargs');
+import * as yargs from 'yargs';
 
 // Examples taken from yargs website
 // https://github.com/chevex/yargs
@@ -343,3 +344,15 @@ function Argv$commandDirWithOptions() {
 		})
 		.argv
 }
+
+// http://yargs.js.org/docs/#methods-failfn
+function Argv$fail() {
+	var argv = yargs
+		.fail(function (msg, err) {
+			if (err) throw err // preserve stack
+			console.error('You broke it!')
+			console.error(msg)
+			process.exit(1)
+		})
+		.argv
+}
diff --git a/yargs/yargs.d.ts b/yargs/yargs.d.ts
index e2f329e3c0..547b6e9e63 100644
--- a/yargs/yargs.d.ts
+++ b/yargs/yargs.d.ts
@@ -135,7 +135,7 @@ declare module "yargs" {
 			count(key: string): Argv;
 			count(keys: string[]): Argv;
 
-			fail(func: (msg: string) => any): void;
+			fail(func: (msg: string, err: Error) => any): Argv;
 		}
 
 		interface RequireDirectoryOptions {