diff --git a/frontend/src/views/Pages/UserProfile/UserCard_FormUsername.spec.js b/frontend/src/views/Pages/UserProfile/UserCard_FormUsername.spec.js
new file mode 100644
index 000000000..b1d705952
--- /dev/null
+++ b/frontend/src/views/Pages/UserProfile/UserCard_FormUsername.spec.js
@@ -0,0 +1,121 @@
+import { mount } from '@vue/test-utils'
+import { extend } from 'vee-validate'
+import UserCardFormUsername from './UserCard_FormUsername'
+import loginAPI from '../../../apis/loginAPI'
+import flushPromises from 'flush-promises'
+
+jest.mock('../../../apis/loginAPI')
+
+extend('gddUsernameRgex', {
+  validate(value) {
+    return true
+  },
+})
+
+extend('gddUsernameUnique', {
+  validate(value) {
+    return true
+  },
+})
+
+const localVue = global.localVue
+
+const mockAPIcall = jest.fn((args) => {
+  return { success: true }
+})
+
+loginAPI.changeUsernameProfile = mockAPIcall
+
+describe('UserCard_FormUsername', () => {
+  let wrapper
+
+  const mocks = {
+    $t: jest.fn((t) => t),
+    $store: {
+      state: {
+        sessionId: 1,
+        email: 'user@example.org',
+        username: '',
+      },
+      commit: jest.fn(),
+    },
+    $toast: {
+      success: jest.fn(),
+    },
+  }
+
+  const Wrapper = () => {
+    return mount(UserCardFormUsername, { localVue, mocks })
+  }
+
+  describe('mount', () => {
+    beforeEach(() => {
+      wrapper = Wrapper()
+    })
+
+    it('renders the component', () => {
+      expect(wrapper.find('div#formusername').exists()).toBeTruthy()
+    })
+
+    describe('username in store is empty', () => {
+      it('renders an empty username', () => {
+        expect(wrapper.find('div.display-username').text()).toEqual('@')
+      })
+
+      it('has an edit icon', () => {
+        expect(wrapper.find('svg.bi-pencil').exists()).toBeTruthy()
+      })
+
+      describe('edit username', () => {
+        beforeEach(async () => {
+          await wrapper.find('svg.bi-pencil').trigger('click')
+        })
+
+        it('shows an input field for the username', () => {
+          expect(wrapper.find('input[placeholder="Username"]').exists()).toBeTruthy()
+        })
+
+        it('shows an cancel icon', () => {
+          expect(wrapper.find('svg.bi-x-circle').exists()).toBeTruthy()
+        })
+
+        it('closes the input when cancel icon is clicked', async () => {
+          wrapper.find('svg.bi-x-circle').trigger('click')
+          await wrapper.vm.$nextTick()
+          expect(wrapper.find('input[placeholder="Username"]').exists()).toBeFalsy()
+        })
+
+        it('does not change the username when cancel is clicked', async () => {
+          wrapper.find('input[placeholder="Username"]').setValue('username')
+          wrapper.find('svg.bi-x-circle').trigger('click')
+          await wrapper.vm.$nextTick()
+          expect(wrapper.find('div.display-username').text()).toEqual('@')
+        })
+
+        it('has a submit button', () => {
+          expect(wrapper.find('button[type="submit"]').exists()).toBeTruthy()
+        })
+
+        describe('successfull submit', () => {
+          beforeEach(async () => {
+            await wrapper.find('input[placeholder="Username"]').setValue('username')
+            await wrapper.find('form').trigger('submit')
+            await flushPromises()
+          })
+
+          it('calls the loginAPI', () => {
+            expect(mockAPIcall).toHaveBeenCalledWith(1, 'user@example.org', 'username')
+          })
+
+          it('displays the new username', () => {
+            expect(wrapper.find('div.display-username').text()).toEqual('@username')
+          })
+
+          it('has no edit button anymore', () => {
+            expect(wrapper.find('svg.bi-pencil').exists()).toBeFalsy()
+          })
+        })
+      })
+    })
+  })
+})
diff --git a/frontend/src/views/Pages/UserProfile/UserCard_FormUsername.vue b/frontend/src/views/Pages/UserProfile/UserCard_FormUsername.vue
index 21fa01aad..e908fd08c 100644
--- a/frontend/src/views/Pages/UserProfile/UserCard_FormUsername.vue
+++ b/frontend/src/views/Pages/UserProfile/UserCard_FormUsername.vue
@@ -26,7 +26,7 @@
         <b-col class="col-lg-3 col-md-10 col-sm-10 text-md-left text-lg-right">
           <small>{{ $t('form.username') }}</small>
         </b-col>
-        <b-col class="col-md-9 col-sm-10">@{{ form.username }}</b-col>
+        <b-col class="col-md-9 col-sm-10 display-username">@{{ username }}</b-col>
       </b-row>
     </b-container>
     <b-container v-else>
@@ -97,7 +97,10 @@ export default {
         this.showUsername = true
         this.$toast.success(this.$t('site.profil.user-data.change-success'))
       } else {
-        alert(result.result.message)
+        this.$toast.error(result.result.message)
+        this.showUsername = true
+        this.username = this.$store.state.username
+        this.form.username = this.$store.state.username
       }
     },
   },