diff --git a/packages/tasq/src/TaskExecutor.test.ts b/packages/tasq/src/TaskExecutor.test.ts
index 08b3b04..08b236e 100644
--- a/packages/tasq/src/TaskExecutor.test.ts
+++ b/packages/tasq/src/TaskExecutor.test.ts
@@ -19,7 +19,7 @@ describe('TaskExecutor', () => {
       await te.wait()
       expect(results).toEqual([10, 5, 7])
     })
-    it.only('executes tasks in different order', async () => {
+    it('executes tasks in different order', async () => {
       const results: number[] = []
       const te = new TaskExecutor<number>(2, async task => {
         await delay(task)
@@ -36,7 +36,13 @@ describe('TaskExecutor', () => {
   })
 
   describe('error handling', () => {
+    it('does not fail on error', async () => {
 
+    })
+
+    it('triggers failure event on error', async () => {
+
+    })
   })
 
 })
diff --git a/packages/tasq/src/TaskExecutor.ts b/packages/tasq/src/TaskExecutor.ts
index 95e4c28..98c82a1 100644
--- a/packages/tasq/src/TaskExecutor.ts
+++ b/packages/tasq/src/TaskExecutor.ts
@@ -5,9 +5,9 @@ export interface ITask<T> {
   execute(): Promise<void>
 }
 
-interface ITaskEvents {
-  success: void
-  failure: Error
+interface ITaskEventHandler {
+  success: () => void
+  failure: (err: Error) => void
 }
 
 export interface ITaskExecutor<T> {
@@ -15,10 +15,10 @@ export interface ITaskExecutor<T> {
 
   wait(): Promise<void>
 
-  addListener<E extends keyof ITaskEvents>(
-    event: E, listener: (value: ITaskEvents[E]) => void): void
-  removeListener<E extends keyof ITaskEvents>(
-    event: E, listener: (value: ITaskEvents[E]) => void): void
+  addListener<E extends keyof ITaskEventHandler>(
+    event: E, listener: ITaskEventHandler[E]): void
+  removeListener<E extends keyof ITaskEventHandler>(
+    event: E, listener: ITaskEventHandler[E]): void
 }
 
 let counter = 0
@@ -34,12 +34,12 @@ export class TaskExecutor<T> implements ITaskExecutor<T> {
   ) {
   }
 
-  addListener<E extends keyof ITaskEvents>(
-    event: E, listener: (value: ITaskEvents[E]) => void): void {
+  addListener<E extends keyof ITaskEventHandler>(
+    event: E, listener: ITaskEventHandler[E]): void {
     this.events.addListener(event, listener)
   }
-  removeListener<E extends keyof ITaskEvents>(
-    event: E, listener: (value: ITaskEvents[E]) => void): void {
+  removeListener<E extends keyof ITaskEventHandler>(
+    event: E, listener: ITaskEventHandler[E]): void {
     this.events.removeListener(event, listener)
   }