diff --git a/packages/backend/src/managers/playground.spec.ts b/packages/backend/src/managers/playground.spec.ts
index 1cee39755..3ff7df873 100644
--- a/packages/backend/src/managers/playground.spec.ts
+++ b/packages/backend/src/managers/playground.spec.ts
@@ -59,6 +59,7 @@ beforeEach(() => {
 });
 
 test('startPlayground should fail if no provider', async () => {
+  mocks.postMessage.mockResolvedValue(undefined);
   mocks.getContainerConnections.mockReturnValue([]);
   await expect(manager.startPlayground('model1', '/path/to/model')).rejects.toThrowError(
     'Unable to find an engine to start playground',
@@ -66,6 +67,7 @@ test('startPlayground should fail if no provider', async () => {
 });
 
 test('startPlayground should download image if not present then create container', async () => {
+  mocks.postMessage.mockResolvedValue(undefined);
   mocks.getContainerConnections.mockReturnValue([
     {
       connection: {
@@ -122,6 +124,7 @@ test('stopPlayground should fail if no playground is running', async () => {
 });
 
 test('stopPlayground should stop a started playground', async () => {
+  mocks.postMessage.mockResolvedValue(undefined);
   mocks.getContainerConnections.mockReturnValue([
     {
       connection: {