TSK-614 BUG to allow update empty wbAccessItems

- Update to empty workbasket access items was not allowed.

lib/taskana-core/src/main/java/pro/taskana/impl/WorkbasketServiceImpl.java

@@ -215,11 +215,13 @@ public class WorkbasketServiceImpl implements WorkbasketService {
                     }
                     newItems.add(wbAccessItemImpl);
                 }
+            }
 
-                // delete all current ones
+            // delete all current ones
-                workbasketAccessMapper.deleteAllAccessItemsForWorkbasketId(workbasketId);
+            workbasketAccessMapper.deleteAllAccessItemsForWorkbasketId(workbasketId);
 
-                // add all
+            // add all
+            if (!newItems.isEmpty()) {
                 newItems.stream().forEach(item -> workbasketAccessMapper.insert(item));
             }
         } finally {
@@ -366,7 +368,7 @@ public class WorkbasketServiceImpl implements WorkbasketService {
 
             if ((originalItem.getAccessId() != null && !originalItem.getAccessId().equals(accessItem.getAccessId()))
                 || (originalItem.getWorkbasketId() != null
-                    && !originalItem.getWorkbasketId().equals(accessItem.getWorkbasketId()))) {
+                && !originalItem.getWorkbasketId().equals(accessItem.getWorkbasketId()))) {
                 throw new InvalidArgumentException(
                     "AccessId and WorkbasketId must not be changed in updateWorkbasketAccessItem calls");
             }

lib/taskana-core/src/test/java/acceptance/workbasket/UpdateWorkbasketAuthorizationsAccTest.java

@@ -205,6 +205,26 @@ public class UpdateWorkbasketAuthorizationsAccTest extends AbstractAccTest {
         assertFalse(item1.isPermTransfer());
     }
 
+    @WithAccessId(
+        userName = "teamlead_1",
+        groupNames = {"group_1", "businessadmin"})
+    @Test
+    public void testUpdatedAccessItemListToEmptyList() throws InvalidArgumentException, NotAuthorizedException {
+        WorkbasketService workbasketService = taskanaEngine.getWorkbasketService();
+        final String wbId = "WBI:100000000000000000000000000000000004";
+        List<WorkbasketAccessItem> accessItems = workbasketService
+            .getWorkbasketAccessItems(wbId);
+        int countBefore = accessItems.size();
+        assertThat(3, equalTo(countBefore));
+
+        workbasketService.setWorkbasketAccessItems(wbId, new ArrayList<>());
+
+        List<WorkbasketAccessItem> updatedAccessItems = workbasketService
+            .getWorkbasketAccessItems(wbId);
+        int countAfter = updatedAccessItems.size();
+        assertThat(0, equalTo(countAfter));
+    }
+
     @WithAccessId(
         userName = "teamlead_1",
         groupNames = {"group_1", "businessadmin"})