diff --git a/src/main/java/fr/plil/sio/persistence/api/GroupService.java b/src/main/java/fr/plil/sio/persistence/api/GroupService.java
index 72daae3..9e85f4b 100644
--- a/src/main/java/fr/plil/sio/persistence/api/GroupService.java
+++ b/src/main/java/fr/plil/sio/persistence/api/GroupService.java
@@ -4,12 +4,12 @@ public interface GroupService {
 
     /**
      * Create a group with a specific name in the database.
-     * There is no two groups with the same name in the database.
+     * There is no two groups with the same name or the same ID in the database.
      *
      * @param name the name of the group
      * @return an instance of the group
      * @throws IllegalArgumentException if name is null
-     * @throws IllegalStateException    if a group with the same name is already present
+     * @throws IllegalStateException if a group with the same name is already present
      */
     Group create(String name);
 
@@ -32,7 +32,7 @@ public interface GroupService {
     Group findByName(String name);
 
     /**
-     * Add a right in the group. Right is inserted at the end of rights list of the group.
+     * Add a right in the group.
      *
      * @param groupName the name of the group.
      * @param right     the right to add
diff --git a/src/main/java/fr/plil/sio/persistence/api/UserService.java b/src/main/java/fr/plil/sio/persistence/api/UserService.java
index 9bad49f..f488e6f 100644
--- a/src/main/java/fr/plil/sio/persistence/api/UserService.java
+++ b/src/main/java/fr/plil/sio/persistence/api/UserService.java
@@ -6,7 +6,7 @@ public interface UserService {
      * Create an user with a specific name in the database and affected to an existing group.
      * There is no two users with the same name in the database.
      *
-     * @param name      the name of the user
+     * @param name the name of the user
      * @param groupName the name of the group
      * @return an instance of the user
      * @throws IllegalArgumentException if name or groupName is null, or if group does not exist.
diff --git a/src/test/java/fr/plil/sio/persistence/jpa/RightServiceTest.java b/src/test/java/fr/plil/sio/persistence/jpa/RightServiceTest.java
index f6d0b4c..c214d9e 100644
--- a/src/test/java/fr/plil/sio/persistence/jpa/RightServiceTest.java
+++ b/src/test/java/fr/plil/sio/persistence/jpa/RightServiceTest.java
@@ -90,7 +90,7 @@ public class RightServiceTest {
     public void testDeleteRightIfNotInDatabase() {
         Right right = new Right();
         right.setName("not-a-right");
-        assertFalse(rightService.delete(right));
+        rightService.delete(right);
     }
 
     @Test(expected = IllegalArgumentException.class)
diff --git a/src/test/java/fr/plil/sio/persistence/jpa/UserServiceTest.java b/src/test/java/fr/plil/sio/persistence/jpa/UserServiceTest.java
index 89e94e6..55d79f8 100644
--- a/src/test/java/fr/plil/sio/persistence/jpa/UserServiceTest.java
+++ b/src/test/java/fr/plil/sio/persistence/jpa/UserServiceTest.java
@@ -70,6 +70,7 @@ public class UserServiceTest {
 
     @Test
     public void testDeleteUserIfNotFound() {
+        userService.delete("user");
         assertFalse(userService.delete("user"));
     }
 
diff --git a/src/test/resources/application.properties b/src/test/resources/application.properties
index d744dce..7db6022 100644
--- a/src/test/resources/application.properties
+++ b/src/test/resources/application.properties
@@ -2,4 +2,4 @@ logging.level.org.springframework=INFO
 logging.level.org.hibernate.SQL=DEBUG
 logging.level.org.hibernate=INFO
 spring.datasource.url=jdbc:h2:mem:persistence;TRACE_LEVEL_FILE=4;
-spring.datasource.tomcat.max-active=300
\ No newline at end of file
+spring.datasource.tomcat.max-active=500
\ No newline at end of file
--
libgit2 0.21.2