diff --git a/lockfile/lockfile-tests.ts b/lockfile/lockfile-tests.ts
index 49aa423d9..9ebb956da 100644
--- a/lockfile/lockfile-tests.ts
+++ b/lockfile/lockfile-tests.ts
@@ -9,6 +9,9 @@ var path: string;
 var opts: lockfile.Options;
 var callback: (err: Error) => {
 
+};
+var callback2: (err: Error, isLocked: boolean) => {
+
 };
 
 opts = {
@@ -25,7 +28,7 @@ lockfile.lockSync(path, opts);
 lockfile.unlock(path, callback);;
 lockfile.unlockSync(path);
 
-lockfile.check(path, opts, callback);
-lockfile.check(path, callback);
+lockfile.check(path, opts, callback2);
+lockfile.check(path, callback2);
 
 bool = lockfile.checkSync(path, opts);
diff --git a/lockfile/lockfile.d.ts b/lockfile/lockfile.d.ts
index 99dfbe28d..1f3acdebc 100644
--- a/lockfile/lockfile.d.ts
+++ b/lockfile/lockfile.d.ts
@@ -18,7 +18,7 @@ declare module 'lockfile' {
 	export function unlock(path: string, callback: (err: Error) => void): void;
 	export function unlockSync(path: string):void;
 
-	export function check(path: string, opts: Options, callback: (err: Error) => void): void;
-	export function check(path: string, callback: (err: Error) => void): void;
+	export function check(path: string, opts: Options, callback: (err: Error, isLocked: boolean) => void): void;
+	export function check(path: string, callback: (err: Error, isLocked: boolean) => void): void;
 	export function checkSync(path: string, opts: Options): boolean;
 }