🧪 Add unit tests for toast utility

apps/mobile/__tests__/toast.test.ts

@@ -0,0 +1,66 @@
+import { toast } from '../src/utils/toast';
+
+describe('toast utility', () => {
+  let mockListener: jest.Mock;
+
+  beforeEach(() => {
+    mockListener = jest.fn();
+  });
+
+  afterEach(() => {
+    // Clear listeners to avoid leaking between tests
+    // Since we don't have a public clear method, we rely on unsubscribe
+    jest.clearAllMocks();
+  });
+
+  it('subscribes and receives a show event', () => {
+    const unsubscribe = toast.subscribe(mockListener);
+    toast.show('Hello World', 'info', 2000);
+
+    expect(mockListener).toHaveBeenCalledTimes(1);
+    expect(mockListener).toHaveBeenCalledWith(
+      expect.objectContaining({
+        message: 'Hello World',
+        type: 'info',
+        duration: 2000,
+        id: expect.any(String)
+      })
+    );
+
+    unsubscribe();
+  });
+
+  it('helper methods work correctly', () => {
+    const unsubscribe = toast.subscribe(mockListener);
+
+    toast.success('Success message');
+    expect(mockListener).toHaveBeenLastCalledWith(
+      expect.objectContaining({ message: 'Success message', type: 'success' })
+    );
+
+    toast.error('Error message');
+    expect(mockListener).toHaveBeenLastCalledWith(
+      expect.objectContaining({ message: 'Error message', type: 'error' })
+    );
+
+    toast.warning('Warning message');
+    expect(mockListener).toHaveBeenLastCalledWith(
+      expect.objectContaining({ message: 'Warning message', type: 'warning' })
+    );
+
+    toast.info('Info message');
+    expect(mockListener).toHaveBeenLastCalledWith(
+      expect.objectContaining({ message: 'Info message', type: 'info' })
+    );
+
+    unsubscribe();
+  });
+
+  it('unsubscribes correctly', () => {
+    const unsubscribe = toast.subscribe(mockListener);
+    unsubscribe();
+
+    toast.show('Test');
+    expect(mockListener).not.toHaveBeenCalled();
+  });
+});