diff --git a/src/main/java/catering/users/UserController.java b/src/main/java/catering/users/UserController.java
index 5404c70..bcfd8f8 100644
--- a/src/main/java/catering/users/UserController.java
+++ b/src/main/java/catering/users/UserController.java
@@ -94,7 +94,7 @@ public class UserController {
 		if (
 			(!result.hasErrors()) &&
 			(!userManagement.getUserByName(form.getUsername()).isEmpty()) &&
-			(userManagement.getUserByAccount(userAccount).get().getUsername() != form.getUsername())
+			(!userManagement.getUserByAccount(userAccount).get().getUsername().equals(form.getUsername()))
 		) {
 			result.rejectValue("username", "username already in use");
 		}
diff --git a/src/test/java/catering/users/UserControllerIntegrationTests.java b/src/test/java/catering/users/UserControllerIntegrationTests.java
index a6456b6..e697378 100644
--- a/src/test/java/catering/users/UserControllerIntegrationTests.java
+++ b/src/test/java/catering/users/UserControllerIntegrationTests.java
@@ -59,6 +59,8 @@ class UserControllerIntegrationTests {
 		createTestUser("paul");
 		createTestUser("mark");
 		createTestUser("eva");
+		createTestUser("sarah");
+		createTestUser("paul");
 	}
 
 	@Test
@@ -353,4 +355,50 @@ class UserControllerIntegrationTests {
 			).andExpect(content().string(containsString("Ungültiger Nutzername")));
 		assertTrue(userAccountManagement.findByUsername("eva").isPresent());
 	}
+
+	@Test
+	@WithMockUser(username = "admin", password = "admin", roles = "ADMIN")
+	void editCustomerDetailsExeptUsername() throws Exception {
+		assertThat(userManagement.getUsers().findAll())
+				.extracting("username", "fullName", "address")
+				.contains(tuple("sarah", "Sarah Klaus", "Baum Weg"));
+		mvc.perform(post("/customers/edit/" + userManagement.getUserByName("sarah").get().getId())
+				// this form of construction is necessary,
+				// because we belive MockMvc internally uses the provided strings directly
+				// this leads to different behavor between tests and browser
+				.param("username", new String("sarah"))
+				.param("fullName", "Sarah Klaus")
+				.param("address", "Baum Straße"))
+				.andExpect(redirectedUrl("/customers"));
+		assertThat(userManagement.getUsers().findAll())
+				.extracting("username", "fullName", "address")
+				.contains(tuple("sarah", "Sarah Klaus", "Baum Straße"));
+		mvc.perform(get("/customers/edit/" + userManagement.getUserByName("sarah").get().getId()))
+				.andExpect(status().isOk())
+				.andExpect(view().name("edit-customer"));
+	}
+
+	@Test
+	@WithMockUser(username = "paul", password = "123")
+	void updateEverythingInProfileExceptUsername() throws Exception {
+		assertTrue(userManagement.getUserByName("paul").isPresent());
+		MockHttpServletRequestBuilder createMessage = post("/profile")
+				.param("username", new String("paul")) // explained above
+				.param("password", "paul")
+				.param("fullName", "Paul")
+				.param("address", "Hotel");
+		mvc.perform(createMessage)
+				.andExpect(status().is3xxRedirection())
+				.andExpect(redirectedUrl("/profile"));
+		assertThat(userManagement.getUsers().findAll())
+				.extracting("username", "fullName", "address")
+				.contains(tuple("paul", "Paul", "Hotel"));
+		MockHttpServletRequestBuilder login = post("/login")
+				.param("username", "paul")
+				.param("password", "paul");
+		mvc.perform(login)
+				.andExpect(status().is3xxRedirection())
+				.andExpect(redirectedUrl("/"));
+	}
+
 }