diff --git a/src/components/UserProfile/UserProfile.test.tsx b/src/components/UserProfile/UserProfile.test.tsx
index 4f11849..e671dce 100644
--- a/src/components/UserProfile/UserProfile.test.tsx
+++ b/src/components/UserProfile/UserProfile.test.tsx
@@ -6,7 +6,7 @@ import { UserProfile } from './UserProfile';
 import translationsMock from '../../translations/translations-mock';
 
 const setup = () => {
-  return render(<UserProfile translations={translationsMock} changeUsername={() => {}}/>)
+  return render(<UserProfile translations={translationsMock} changeUsername={()=>''}/>)
 };
 
 describe('UserProfile component', () => {
diff --git a/src/components/UserProfile/UserProfile.tsx b/src/components/UserProfile/UserProfile.tsx
index 29241c9..4b2876a 100644
--- a/src/components/UserProfile/UserProfile.tsx
+++ b/src/components/UserProfile/UserProfile.tsx
@@ -10,7 +10,7 @@ interface IUserProfileState {
   username: string;
 }
 
-export class UserProfile extends React.Component<{ translations: IAppContext }> {
+export class UserProfile extends React.Component<{ translations: IAppContext, changeUsername: (val: string) => void }> {
   public state: IUserProfileState = {
     username: readRecord('username') || 'guest0001'
   };