diff --git a/goofy-server/src/main/java/de/itvsh/goofy/historie/HistorieModelAssembler.java b/goofy-server/src/main/java/de/itvsh/goofy/historie/HistorieModelAssembler.java
index f5636484ffbf7c553ad7d54b26629066133e1310..15719a6c8a6f97382dafa786832fc7d1de8c2384 100644
--- a/goofy-server/src/main/java/de/itvsh/goofy/historie/HistorieModelAssembler.java
+++ b/goofy-server/src/main/java/de/itvsh/goofy/historie/HistorieModelAssembler.java
@@ -35,7 +35,7 @@ class HistorieModelAssembler implements RepresentationModelAssembler<Command, En
 	}
 
 	Command unsetSystemUser(Command entity) {
-		if (Objects.nonNull(entity.getCreatedBy()) && entity.getCreatedBy().toString().startsWith(SYSTEM_NOTIFICATION_MANAGER_PREFIX)) {
+		if (isSystemNotificationUser(entity)) {
 			return entity.toBuilder().createdBy(null).build();
 		}
 
@@ -43,6 +43,10 @@ class HistorieModelAssembler implements RepresentationModelAssembler<Command, En
 
 	}
 
+	private boolean isSystemNotificationUser(Command entity) {
+		return Objects.nonNull(entity.getCreatedBy()) && entity.getCreatedBy().toString().startsWith(SYSTEM_NOTIFICATION_MANAGER_PREFIX);
+	}
+
 	private void addAssignedTo(Command entity, ModelBuilder<Command> modelBuilder) {
 		Optional.ofNullable(entity.getBody()).map(body -> body.get(ASSIGNED_TO_BODY_FIELD))
 				.ifPresent(assignedTo -> modelBuilder.addLink(linkTo(UserProfileController.class).slash(assignedTo).withRel(REL_ASSIGNED_TO)));
diff --git a/goofy-server/src/test/java/de/itvsh/goofy/historie/HistorieModelAssemblerTest.java b/goofy-server/src/test/java/de/itvsh/goofy/historie/HistorieModelAssemblerTest.java
index 49e336a51a35340a38cde013183d76c4f51a665a..824d8d08f59e6439463026eb40f24f0430e58aaf 100644
--- a/goofy-server/src/test/java/de/itvsh/goofy/historie/HistorieModelAssemblerTest.java
+++ b/goofy-server/src/test/java/de/itvsh/goofy/historie/HistorieModelAssemblerTest.java
@@ -17,6 +17,10 @@ import de.itvsh.goofy.common.user.UserProfileTestFactory;
 
 class HistorieModelAssemblerTest {
 
+	private static final String USER_PROFILES_API_PATH = "/api/userProfiles/";
+
+	private static final String CREATED_BY = "createdBy";
+
 	@InjectMocks
 	private HistorieModelAssembler modelAssembler;
 
@@ -29,14 +33,6 @@ class HistorieModelAssemblerTest {
 		assertThat(model.getLink(IanaLinkRelations.SELF)).isPresent().get().extracting(Link::getHref).isEqualTo(COMMAND_SINGLE_PATH);
 	}
 
-	@Test
-	void shouldHaveCreatedByLink() {
-		var model = modelAssembler.toModel(CommandTestFactory.create());
-
-		assertThat(model.getLink("createdBy")).isPresent().get().extracting(Link::getHref)
-				.isEqualTo("/api/userProfiles/" + UserProfileTestFactory.ID);
-	}
-
 	@DisplayName("AssignedTo Link")
 	@Nested
 	class TestAssignedToLink {
@@ -47,7 +43,7 @@ class HistorieModelAssemblerTest {
 					.body(Map.of(HistorieModelAssembler.ASSIGNED_TO_BODY_FIELD, UserProfileTestFactory.ID)).build());
 
 			assertThat(model.getLink(HistorieModelAssembler.REL_ASSIGNED_TO)).isPresent().get().extracting(Link::getHref)
-					.isEqualTo("/api/userProfiles/" + UserProfileTestFactory.ID);
+					.isEqualTo(USER_PROFILES_API_PATH + UserProfileTestFactory.ID);
 		}
 
 		@Test
@@ -61,12 +57,13 @@ class HistorieModelAssemblerTest {
 	@DisplayName("createdBy Link")
 	@Nested
 	class TestCreatedByLink {
+
 		@Test
 		void shouldExistingAtUser() {
 			var model = modelAssembler.toModel(CommandTestFactory.create());
 
-			assertThat(model.getLink("createdBy")).isPresent().get().extracting(Link::getHref)
-					.isEqualTo("/api/userProfiles/" + UserProfileTestFactory.ID);
+			assertThat(model.getLink(CREATED_BY)).isPresent().get().extracting(Link::getHref)
+					.isEqualTo(USER_PROFILES_API_PATH + UserProfileTestFactory.ID);
 		}
 
 		@Test
@@ -75,14 +72,14 @@ class HistorieModelAssemblerTest {
 					.toModel(CommandTestFactory.createBuilder().createdBy(UserId.from(HistorieModelAssembler.SYSTEM_NOTIFICATION_MANAGER_PREFIX))
 							.build());
 
-			assertThat(model.getLink("createdBy")).isNotPresent();
+			assertThat(model.getLink(CREATED_BY)).isNotPresent();
 		}
 
 		@Test
 		void shouldNotBePresentOnNullValue() {
 			var model = modelAssembler.toModel(CommandTestFactory.createBuilder().createdBy(null).build());
 
-			assertThat(model.getLink("createdBy")).isNotPresent();
+			assertThat(model.getLink(CREATED_BY)).isNotPresent();
 		}
 	}
 }
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