diff --git a/ccm-core/src/main/java/org/libreccm/security/GroupManager.java b/ccm-core/src/main/java/org/libreccm/security/GroupManager.java
index 326643beb..80bcc3da6 100644
--- a/ccm-core/src/main/java/org/libreccm/security/GroupManager.java
+++ b/ccm-core/src/main/java/org/libreccm/security/GroupManager.java
@@ -62,6 +62,7 @@ public class GroupManager implements Serializable {
     @RequiresPrivilege(CoreConstants.PRIVILEGE_ADMIN)
     @Transactional(Transactional.TxType.REQUIRED)
     public void addMemberToGroup(final User user, final Group group) {
+        
         if (user == null) {
             throw new IllegalArgumentException(
                 "Can't add null as user to a group.");
diff --git a/ccm-core/src/main/java/org/libreccm/security/GroupRepository.java b/ccm-core/src/main/java/org/libreccm/security/GroupRepository.java
index 1e49d9032..46b641649 100644
--- a/ccm-core/src/main/java/org/libreccm/security/GroupRepository.java
+++ b/ccm-core/src/main/java/org/libreccm/security/GroupRepository.java
@@ -24,8 +24,10 @@ import org.libreccm.core.CoreConstants;
 import javax.enterprise.context.RequestScoped;
 import javax.persistence.TypedQuery;
 import javax.transaction.Transactional;
+
 import java.util.List;
 import java.util.Optional;
+import java.util.UUID;
 
 /**
  * Repository for groups.
@@ -132,6 +134,12 @@ public class GroupRepository extends AbstractEntityRepository<Long, Group> {
     public void save(final Group group) {
         super.save(group);
     }
+    
+    @Override
+    public void initNewEntity(final Group group) {
+        
+        group.setUuid(UUID.randomUUID().toString());
+    }
 
     @AuthorizationRequired
     @RequiresPrivilege(CoreConstants.PRIVILEGE_ADMIN)
diff --git a/ccm-core/src/test/java/org/libreccm/security/GroupManagerTest.java b/ccm-core/src/test/java/org/libreccm/security/GroupManagerTest.java
index 601a47d8e..632ead654 100644
--- a/ccm-core/src/test/java/org/libreccm/security/GroupManagerTest.java
+++ b/ccm-core/src/test/java/org/libreccm/security/GroupManagerTest.java
@@ -153,8 +153,10 @@ public class GroupManagerTest {
     @Test
     @UsingDataSet("datasets/org/libreccm/security/GroupManagerTest/data.yml")
     @ShouldMatchDataSet(
-        value = "datasets/org/libreccm/security/GroupManagerTest/after-add.yml",
-        excludeColumns = {"membership_id"})
+        excludeColumns = {"membership_id", "uuid"},
+        orderBy = {"group_memberships.membership_id"},
+        value = "datasets/org/libreccm/security/GroupManagerTest/after-add.yml"
+    )
     @InSequence(200)
     public void addUserToGroup() {
         final Group admins = groupRepository.findByName("admins").get();
diff --git a/ccm-core/src/test/java/org/libreccm/security/GroupRepositoryTest.java b/ccm-core/src/test/java/org/libreccm/security/GroupRepositoryTest.java
index 9fc154564..212fc7b26 100644
--- a/ccm-core/src/test/java/org/libreccm/security/GroupRepositoryTest.java
+++ b/ccm-core/src/test/java/org/libreccm/security/GroupRepositoryTest.java
@@ -149,15 +149,15 @@ public class GroupRepositoryTest {
                              final Optional<Group> editors,
                              final Optional<Group> none) {
         assertThat(admins.isPresent(), is(true));
-        assertThat(admins.get().getPartyId(), is(-10L));
+        assertThat(admins.get().getPartyId(), is(10L));
         assertThat(admins.get().getName(), is(equalTo(ADMINS)));
 
         assertThat(users.isPresent(), is(true));
-        assertThat(users.get().getPartyId(), is(-20L));
+        assertThat(users.get().getPartyId(), is(20L));
         assertThat(users.get().getName(), is(equalTo(USERS)));
 
         assertThat(editors.isPresent(), is(true));
-        assertThat(editors.get().getPartyId(), is(-30L));
+        assertThat(editors.get().getPartyId(), is(30L));
         assertThat(editors.get().getName(), is(equalTo(EDITORS)));
 
         assertThat(none.isPresent(), is(false));
@@ -167,10 +167,10 @@ public class GroupRepositoryTest {
     @UsingDataSet("datasets/org/libreccm/security/GroupRepositoryTest/data.yml")
     @InSequence(100)
     public void findGroupById() {
-        final Optional<Group> admins = groupRepository.findById(-10L);
-        final Optional<Group> users = groupRepository.findById(-20L);
-        final Optional<Group> editors = groupRepository.findById(-30L);
-        final Optional<Group> none = groupRepository.findById(-999L);
+        final Optional<Group> admins = groupRepository.findById(10L);
+        final Optional<Group> users = groupRepository.findById(20L);
+        final Optional<Group> editors = groupRepository.findById(30L);
+        final Optional<Group> none = groupRepository.findById(999L);
 
         checkGroups(admins, users, editors, none);
     }
@@ -198,9 +198,11 @@ public class GroupRepositoryTest {
 
     @Test
     @UsingDataSet("datasets/org/libreccm/security/GroupRepositoryTest/data.yml")
-    @ShouldMatchDataSet(value = "datasets/org/libreccm/security/"
-                                    + "GroupRepositoryTest/after-save-new.yml",
-                        excludeColumns = {"party_id"})
+    @ShouldMatchDataSet(
+        excludeColumns = {"party_id", "uuid"},
+        value = "datasets/org/libreccm/security/"
+                    + "GroupRepositoryTest/after-save-new.yml"
+    )
     @InSequence(400)
     public void saveNewGroup() {
         final Group authors = new Group();
@@ -216,7 +218,7 @@ public class GroupRepositoryTest {
                         excludeColumns = {"party_id"})
     @InSequence(500)
     public void saveChangedGroup() {
-        final Group group = groupRepository.findById(-30L).get();
+        final Group group = groupRepository.findById(30L).get();
         group.setName("authors");
 
         groupRepository.save(group);
diff --git a/ccm-core/src/test/java/org/libreccm/security/PartyRepositoryTest.java b/ccm-core/src/test/java/org/libreccm/security/PartyRepositoryTest.java
index 047c06c0e..722609114 100644
--- a/ccm-core/src/test/java/org/libreccm/security/PartyRepositoryTest.java
+++ b/ccm-core/src/test/java/org/libreccm/security/PartyRepositoryTest.java
@@ -151,11 +151,11 @@ public class PartyRepositoryTest {
     @UsingDataSet("datasets/org/libreccm/security/PartyRepositoryTest/data.yml")
     @InSequence(100)
     public void findPartyById() {
-        final User jdoe = (User) partyRepository.findById(-10L).get();
-        final Group admins = (Group) partyRepository.findById(-20L).get();
+        final User jdoe = (User) partyRepository.findById(10L).get();
+        final Group admins = (Group) partyRepository.findById(20L).get();
 
         assertThat(jdoe, is(not(nullValue())));
-        assertThat(jdoe.getPartyId(), is(-10L));
+        assertThat(jdoe.getPartyId(), is(10L));
         assertThat(jdoe.getName(), is(equalTo(JDOE)));
         assertThat(jdoe.getFamilyName(), is(equalTo("Doe")));
         assertThat(jdoe.getGivenName(), is(equalTo("John")));
@@ -164,7 +164,7 @@ public class PartyRepositoryTest {
                        "$shiro1$SHA-512$500000$7xkDcZUN0/whJInHIvGsDw==$WhelBVmJU/cLV7lAkMOrE5B/mqCW0bUuid1WX+xBwzzAaekC5bYn9eeOFGJWhiDgmaC50ZCUmM96/iGsRoc4uA==")));
 
         assertThat(admins, is(not(nullValue())));
-        assertThat(admins.getPartyId(), is(-20L));
+        assertThat(admins.getPartyId(), is(20L));
         assertThat(admins.getName(), is(equalTo(ADMINS)));
     }
 
@@ -176,7 +176,7 @@ public class PartyRepositoryTest {
         final Group admins = (Group) partyRepository.findByName(ADMINS).get();
 
         assertThat(jdoe, is(not(nullValue())));
-        assertThat(jdoe.getPartyId(), is(-10L));
+        assertThat(jdoe.getPartyId(), is(10L));
         assertThat(jdoe.getName(), is(equalTo(JDOE)));
         assertThat(jdoe.getFamilyName(), is(equalTo("Doe")));
         assertThat(jdoe.getGivenName(), is(equalTo("John")));
@@ -185,7 +185,7 @@ public class PartyRepositoryTest {
                        "$shiro1$SHA-512$500000$7xkDcZUN0/whJInHIvGsDw==$WhelBVmJU/cLV7lAkMOrE5B/mqCW0bUuid1WX+xBwzzAaekC5bYn9eeOFGJWhiDgmaC50ZCUmM96/iGsRoc4uA==")));
 
         assertThat(admins, is(not(nullValue())));
-        assertThat(admins.getPartyId(), is(-20L));
+        assertThat(admins.getPartyId(), is(20L));
         assertThat(admins.getName(), is(equalTo(ADMINS)));
     }
 
@@ -200,9 +200,10 @@ public class PartyRepositoryTest {
 
     @Test
     @UsingDataSet("datasets/org/libreccm/security/PartyRepositoryTest/data.yml")
-    @ShouldMatchDataSet(value = "datasets/org/libreccm/security/"
-                                    + "PartyRepositoryTest/after-save-new.yml",
-                        excludeColumns = {"party_id", "password"}
+    @ShouldMatchDataSet(
+        excludeColumns = {"party_id", "uuid", "password"},
+        value = "datasets/org/libreccm/security/"
+                    + "PartyRepositoryTest/after-save-new.yml"
     )
     @InSequence(300)
     public void saveNewParty() {
@@ -238,8 +239,8 @@ public class PartyRepositoryTest {
     )
     @InSequence(400)
     public void saveChangedParty() {
-        final Party user = partyRepository.findById(-10L).get();
-        final Party group = partyRepository.findById(-20L).get();
+        final Party user = partyRepository.findById(10L).get();
+        final Party group = partyRepository.findById(20L).get();
 
         user.setName("johndoe");
         group.setName("managers");
@@ -264,7 +265,7 @@ public class PartyRepositoryTest {
                         excludeColumns = {"party_id"})
     @InSequence(600)
     public void deleteParty() {
-        final Party user = partyRepository.findById(-10L).get();
+        final Party user = partyRepository.findById(10L).get();
 
         shiro.getSystemUser().execute(() -> partyRepository.delete(user));
     }
diff --git a/ccm-core/src/test/resources/datasets/org/libreccm/security/GroupManagerTest/after-add.yml b/ccm-core/src/test/resources/datasets/org/libreccm/security/GroupManagerTest/after-add.yml
index 913b52c26..fc3872825 100644
--- a/ccm-core/src/test/resources/datasets/org/libreccm/security/GroupManagerTest/after-add.yml
+++ b/ccm-core/src/test/resources/datasets/org/libreccm/security/GroupManagerTest/after-add.yml
@@ -1,26 +1,26 @@
 ccm_core.parties:
     # John Doe
-    - party_id": 10
+    - party_id: 10
       uuid: 631be113-7e86-453d-9f8b-8cb6cb6df268
       name: jdoe
     # Max Muster
-    - party_id": 20
+    - party_id: 20
       uuid: 3a61d302-97a5-4e46-bbc9-8d716f7c54c4
       name: mmuster
     # Joe Public
-    - party_id": 30
+    - party_id: 30
       uuid: 7d5ad4a7-c2bd-4e49-8716-0bfb40413c75
       name: joe
     # admins
-    - party_id": 40
+    - party_id: 40
       uuid: 0fc446b7-a242-4407-9d04-b8ccaaa9dee5
       name: admins
     # users
-    - party_id": 50
+    - party_id: 50
       uuid: 2082d7fc-8268-4195-8cbe-eb826b1afaeb
       name: users
     # editors
-    - party_id": 60
+    - party_id: 60
       uuid: 176bfecc-c0fa-4e76-8935-5d6d0ec60e8c
       name: editors
 ccm_core.users:
@@ -30,7 +30,7 @@ ccm_core.users:
       email_address: john.doe@example.com
       family_name: Doe
       given_name: John
-      party_id": 10
+      party_id: 10
       # foo123
       password: $shiro1$SHA-512$500000$7xkDcZUN0/whJInHIvGsDw==$WhelBVmJU/cLV7lAkMOrE5B/mqCW0bUuid1WX+xBwzzAaekC5bYn9eeOFGJWhiDgmaC50ZCUmM96/iGsRoc4uA==
       password_reset_required: false
@@ -41,7 +41,7 @@ ccm_core.users:
       email_address: max.mustermann@example.org
       family_name: Mustermann
       given_name: Max
-      party_id": 20
+      party_id: 20
       # foo123
       password: $shiro1$SHA-512$500000$Y7CnccN1h25sR7KCElMOXg==$CVLWBhetodaEzzhDfGjRcCFZtSW02xOnjH7xhBx0lbxO66grKIt6LWmXoUhLEydce1JZ7cbzNLYOxIwwTeqi5Q==
       password_reset_required: false
@@ -52,45 +52,45 @@ ccm_core.users:
       email_address: joe.public@example.com
       family_name: Public
       given_name: Joe
-      party_id": 30
+      party_id: 30
       password: $shiro1$SHA-512$500000$RUCYXAQt+XzUmj3x8oG5gw==$qU+lX160Jc6sNUOI9X85wlf2lzn4/hLJNURtjmw9LOYJ7vAqUFFmhyNCMxpzuHIpzeMELr+A0XReoSmtcZnOOw==
       password_reset_required: false
       verified: true
 ccm_core.groups:
     # admins
-    - party_id": 40
+    - party_id: 40
     # users
-    - party_id": 50
+    - party_id: 50
     # editors
-    - party_id": 60
+    - party_id: 60
 ccm_core.group_memberships:
     # admins <-> jdoe
-    - membership_id": 100
+    - membership_id: 100
       uuid: 1f9dad0a-c51a-49e7-8720-c3c669cde67e
-      group_id": 40
-      member_id": 10
+      group_id: 40
+      member_id: 10
     # users <-> mmuster
-    - membership_id": 200
+    - membership_id: 200
       uuid: 3837b1c2-b4e4-44b9-a92f-2330d76b51df
-      group_id": 50
-      member_id": 20
+      group_id: 50
+      member_id: 20
     # users <-> joe
-    - membership_id": 300
+    - membership_id: 300
       uuid: cf8ffbc6-96d3-4e23-9503-4b396ea112aa
-      group_id": 50
-      member_id": 30
+      group_id: 50
+      member_id: 30
     # editors <-> joe
-    - membership_id": 400
+    - membership_id: 400
       uuid: 610ad227-cc55-4a8f-b532-3a5204f9d2dd
-      group_id": 60
-      member_id": 30
+      group_id: 60
+      member_id: 30
       # admins <-> mmuster
-    - membership_id": 500
+    - membership_id: 500
       uuid: 555657c8-e8ce-41e1-a327-f853901c8813
-      group_id": 40
-      member_id": 20
+      group_id: 40
+      member_id: 20
     # editors <-> jdoe
-    - membership_id": 600
+    - membership_id: 600
       uuid: ed78b175-3ff3-4f34-8a5f-829e2113c593
-      group_id": 60
-      member_id": 10
\ No newline at end of file
+      group_id: 60
+      member_id: 10
\ No newline at end of file
diff --git a/ccm-core/src/test/resources/datasets/org/libreccm/security/GroupManagerTest/after-remove.yml b/ccm-core/src/test/resources/datasets/org/libreccm/security/GroupManagerTest/after-remove.yml
index 0fef856a8..77c0e8f70 100644
--- a/ccm-core/src/test/resources/datasets/org/libreccm/security/GroupManagerTest/after-remove.yml
+++ b/ccm-core/src/test/resources/datasets/org/libreccm/security/GroupManagerTest/after-remove.yml
@@ -1,26 +1,26 @@
 ccm_core.parties:
     # John Doe
-    - party_id": 10
+    - party_id: 10
       uuid: 631be113-7e86-453d-9f8b-8cb6cb6df268
       name: jdoe
     # Max Muster
-    - party_id": 20
+    - party_id: 20
       uuid: 3a61d302-97a5-4e46-bbc9-8d716f7c54c4
       name: mmuster
     # Joe Public
-    - party_id": 30
+    - party_id: 30
       uuid: 7d5ad4a7-c2bd-4e49-8716-0bfb40413c75
       name: joe
     # admins
-    - party_id": 40
+    - party_id: 40
       uuid: 0fc446b7-a242-4407-9d04-b8ccaaa9dee5
       name: admins
     # users
-    - party_id": 50
+    - party_id: 50
       uuid: 2082d7fc-8268-4195-8cbe-eb826b1afaeb
       name: users
     # editors
-    - party_id": 60
+    - party_id: 60
       uuid: 176bfecc-c0fa-4e76-8935-5d6d0ec60e8c
       name: editors
 ccm_core.users:
@@ -30,7 +30,7 @@ ccm_core.users:
       email_address: john.doe@example.com
       family_name: Doe
       given_name: John
-      party_id": 10
+      party_id: 10
       # foo123
       password: $shiro1$SHA-512$500000$7xkDcZUN0/whJInHIvGsDw==$WhelBVmJU/cLV7lAkMOrE5B/mqCW0bUuid1WX+xBwzzAaekC5bYn9eeOFGJWhiDgmaC50ZCUmM96/iGsRoc4uA==
       password_reset_required: false
@@ -41,7 +41,7 @@ ccm_core.users:
       email_address: max.mustermann@example.org
       family_name: Mustermann
       given_name: Max
-      party_id": 20
+      party_id: 20
       # foo123
       password: $shiro1$SHA-512$500000$Y7CnccN1h25sR7KCElMOXg==$CVLWBhetodaEzzhDfGjRcCFZtSW02xOnjH7xhBx0lbxO66grKIt6LWmXoUhLEydce1JZ7cbzNLYOxIwwTeqi5Q==
       password_reset_required: false
@@ -52,25 +52,25 @@ ccm_core.users:
       email_address: joe.public@example.com
       family_name: Public
       given_name: Joe
-      party_id": 30
+      party_id: 30
       password: $shiro1$SHA-512$500000$RUCYXAQt+XzUmj3x8oG5gw==$qU+lX160Jc6sNUOI9X85wlf2lzn4/hLJNURtjmw9LOYJ7vAqUFFmhyNCMxpzuHIpzeMELr+A0XReoSmtcZnOOw==
       password_reset_required: false
       verified: true
 ccm_core.groups:
     # admins
-    - party_id": 40
+    - party_id: 40
     # users
-    - party_id": 50
+    - party_id: 50
     # editors
-    - party_id": 60
+    - party_id: 60
 ccm_core.group_memberships:
     # users <-> joe
-    - membership_id": 300
+    - membership_id: 300
       uuid: cf8ffbc6-96d3-4e23-9503-4b396ea112aa
-      group_id": 50
-      member_id": 30
+      group_id: 50
+      member_id: 30
     # editors <-> joe
-    - membership_id": 400
+    - membership_id: 400
       uuid: 610ad227-cc55-4a8f-b532-3a5204f9d2dd
-      group_id": 60
-      member_id": 30
\ No newline at end of file
+      group_id: 60
+      member_id: 30
\ No newline at end of file
diff --git a/ccm-core/src/test/resources/datasets/org/libreccm/security/GroupManagerTest/data.yml b/ccm-core/src/test/resources/datasets/org/libreccm/security/GroupManagerTest/data.yml
index d4d58fc68..a5bc9b55c 100644
--- a/ccm-core/src/test/resources/datasets/org/libreccm/security/GroupManagerTest/data.yml
+++ b/ccm-core/src/test/resources/datasets/org/libreccm/security/GroupManagerTest/data.yml
@@ -1,26 +1,26 @@
 ccm_core.parties:
     # John Doe
-    - party_id": 10
+    - party_id: 10
       uuid: 631be113-7e86-453d-9f8b-8cb6cb6df268
       name: jdoe
     # Max Muster
-    - party_id": 20
+    - party_id: 20
       uuid: 3a61d302-97a5-4e46-bbc9-8d716f7c54c4
       name: mmuster
     # Joe Public
-    - party_id": 30
+    - party_id: 30
       uuid: 7d5ad4a7-c2bd-4e49-8716-0bfb40413c75
       name: joe
     # admins
-    - party_id": 40
+    - party_id: 40
       uuid: 0fc446b7-a242-4407-9d04-b8ccaaa9dee5
       name: admins
     # users
-    - party_id": 50
+    - party_id: 50
       uuid: 2082d7fc-8268-4195-8cbe-eb826b1afaeb
       name: users
     # editors
-    - party_id": 60
+    - party_id: 60
       uuid: 176bfecc-c0fa-4e76-8935-5d6d0ec60e8c
       name: editors
 ccm_core.users:
@@ -30,7 +30,7 @@ ccm_core.users:
       email_address: john.doe@example.com
       family_name: Doe
       given_name: John
-      party_id": 10
+      party_id: 10
       # foo123
       password: $shiro1$SHA-512$500000$7xkDcZUN0/whJInHIvGsDw==$WhelBVmJU/cLV7lAkMOrE5B/mqCW0bUuid1WX+xBwzzAaekC5bYn9eeOFGJWhiDgmaC50ZCUmM96/iGsRoc4uA==
       password_reset_required: false
@@ -41,7 +41,7 @@ ccm_core.users:
       email_address: max.mustermann@example.org
       family_name: Mustermann
       given_name: Max
-      party_id": 20
+      party_id: 20
       # foo123
       password: $shiro1$SHA-512$500000$Y7CnccN1h25sR7KCElMOXg==$CVLWBhetodaEzzhDfGjRcCFZtSW02xOnjH7xhBx0lbxO66grKIt6LWmXoUhLEydce1JZ7cbzNLYOxIwwTeqi5Q==
       password_reset_required: false
@@ -52,35 +52,35 @@ ccm_core.users:
       email_address: joe.public@example.com
       family_name: Public
       given_name: Joe
-      party_id": 30
+      party_id: 30
       password: $shiro1$SHA-512$500000$RUCYXAQt+XzUmj3x8oG5gw==$qU+lX160Jc6sNUOI9X85wlf2lzn4/hLJNURtjmw9LOYJ7vAqUFFmhyNCMxpzuHIpzeMELr+A0XReoSmtcZnOOw==
       password_reset_required: false
       verified: true
 ccm_core.groups:
     # admins
-    - party_id": 40
+    - party_id: 40
     # users
-    - party_id": 50
+    - party_id: 50
     # editors
-    - party_id": 60
+    - party_id: 60
 ccm_core.group_memberships:
     # admins <-> jdoe
-    - membership_id": 100
+    - membership_id: 100
       uuid: 1f9dad0a-c51a-49e7-8720-c3c669cde67e
-      group_id": 40
-      member_id": 10
+      group_id: 40
+      member_id: 10
     # users <-> mmuster
-    - membership_id": 200
+    - membership_id: 200
       uuid: 3837b1c2-b4e4-44b9-a92f-2330d76b51df
-      group_id": 50
-      member_id": 20
+      group_id: 50
+      member_id: 20
     # users <-> joe
-    - membership_id": 300
+    - membership_id: 300
       uuid: cf8ffbc6-96d3-4e23-9503-4b396ea112aa
-      group_id": 50
-      member_id": 30
+      group_id: 50
+      member_id: 30
     # editors <-> joe
-    - membership_id": 400
+    - membership_id: 400
       uuid: 610ad227-cc55-4a8f-b532-3a5204f9d2dd
-      group_id": 60
-      member_id": 30
\ No newline at end of file
+      group_id: 60
+      member_id: 30
\ No newline at end of file
diff --git a/ccm-core/src/test/resources/datasets/org/libreccm/security/PartyRepositoryTest/after-save-changed.yml b/ccm-core/src/test/resources/datasets/org/libreccm/security/PartyRepositoryTest/after-save-changed.yml
index e75332768..e41c6067d 100644
--- a/ccm-core/src/test/resources/datasets/org/libreccm/security/PartyRepositoryTest/after-save-changed.yml
+++ b/ccm-core/src/test/resources/datasets/org/libreccm/security/PartyRepositoryTest/after-save-changed.yml
@@ -2,7 +2,7 @@ ccm_core.parties:
     # John Doe
     - party_id: 10
       uuid: 631be113-7e86-453d-9f8b-8cb6cb6df268
-      name: jdoe
+      name: johndoe
     - party_id: 20
       uuid: 3a61d302-97a5-4e46-bbc9-8d716f7c54c4
       name: managers