diff --git a/COMET.Web.Common.Tests/Extensions/SessionServiceExtensionsTestFixture.cs b/COMET.Web.Common.Tests/Extensions/SessionServiceExtensionsTestFixture.cs
new file mode 100644
index 00000000..c946fbec
--- /dev/null
+++ b/COMET.Web.Common.Tests/Extensions/SessionServiceExtensionsTestFixture.cs
@@ -0,0 +1,91 @@
+// --------------------------------------------------------------------------------------------------------------------
+//  <copyright file="SessionServiceExtensionsTestFixture.cs" company="RHEA System S.A.">
+//     Copyright (c) 2023 RHEA System S.A.
+// 
+//     Authors: Sam Gerené, Alex Vorobiev, Alexander van Delft, Jaime Bernar, Théate Antoine
+// 
+//     This file is part of COMET WEB Community Edition
+//     The COMET WEB Community Edition is the RHEA Web Application implementation of ECSS-E-TM-10-25 Annex A and Annex C.
+// 
+//     The COMET WEB Community Edition is free software; you can redistribute it and/or
+//     modify it under the terms of the GNU Affero General Public
+//     License as published by the Free Software Foundation; either
+//     version 3 of the License, or (at your option) any later version.
+// 
+//     The COMET WEB Community Edition is distributed in the hope that it will be useful,
+//     but WITHOUT ANY WARRANTY; without even the implied warranty of
+//     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+//    Affero General Public License for more details.
+// 
+//    You should have received a copy of the GNU Affero General Public License
+//    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+//  </copyright>
+//  --------------------------------------------------------------------------------------------------------------------
+
+namespace COMET.Web.Common.Tests.Extensions
+{
+    using CDP4Common.EngineeringModelData;
+    using CDP4Common.SiteDirectoryData;
+
+    using CDP4Dal;
+    using CDP4Dal.Operations;
+
+    using COMET.Web.Common.Extensions;
+    using COMET.Web.Common.Services.SessionManagement;
+    using Microsoft.Extensions.Logging;
+    using Moq;
+    using NUnit.Framework;
+
+    [TestFixture]
+    public class SessionServiceExtensionsTestFixture
+    {
+        private Mock<ISession> session;
+        private ISessionService sessionService;
+
+        [SetUp]
+        public void Setup()
+        {
+            var logger = new Mock<ILogger<SessionService>>();
+
+            this.session = new Mock<ISession>();
+            this.sessionService = new SessionService(logger.Object)
+            {
+                Session = this.session.Object
+            };
+        }
+
+        [Test]
+        public void VerifyAddParameter()
+        {
+            var model = new EngineeringModel();
+            var iterationSetup = new IterationSetup();
+            var iteration = new Iteration()
+            {
+                IterationSetup = iterationSetup,
+                Container = model
+            };
+            model.Iteration.Add(iteration);
+
+            var elementDefinition = new ElementDefinition();
+            iteration.Element.Add(elementDefinition);
+
+            var textParameterType = new TextParameterType();
+
+            var doe = new DomainOfExpertise()
+            {
+                Name = "doe",
+                ShortName = "doe"
+            };
+
+            Assert.Multiple(() =>
+            {
+                Assert.That(() => this.sessionService.AddParameter(null, null, null, null, null), Throws.ArgumentNullException);
+                Assert.That(() => this.sessionService.AddParameter(elementDefinition, null, null, null, null), Throws.ArgumentNullException);
+                Assert.That(() => this.sessionService.AddParameter(elementDefinition, null, textParameterType, null, null), Throws.ArgumentNullException);
+                Assert.That(() => this.sessionService.AddParameter(elementDefinition, null, textParameterType, null, doe), Throws.Nothing);
+            });
+
+            this.session.Verify(x => x.Write(It.IsAny<OperationContainer>()), Times.Once);
+        }
+    }
+}
diff --git a/COMET.Web.Common/Extensions/SessionServiceExtensions.cs b/COMET.Web.Common/Extensions/SessionServiceExtensions.cs
index b08eedd1..821d0f4c 100644
--- a/COMET.Web.Common/Extensions/SessionServiceExtensions.cs
+++ b/COMET.Web.Common/Extensions/SessionServiceExtensions.cs
@@ -36,27 +36,6 @@ namespace COMET.Web.Common.Extensions
     /// </summary>
     public static class SessionServiceExtensions
     {
-        /// <summary>
-        /// Marks a top element for a given iteration
-        /// </summary>
-        /// <param name="sessionService">The <see cref="ISessionService"/> in which the iteration will be updated</param>
-        /// <param name="iteration">The <see cref="Iteration"/> to be updated</param>
-        /// <param name="element">The <see cref="ElementDefinition"/> to be marked as top element</param>
-        /// <returns>A <see cref="Task"/></returns>
-        /// <exception cref="ArgumentNullException">Throws an <see cref="ArgumentException"/></exception>
-        public static async Task<Result> MarkTopElement(this ISessionService sessionService, Iteration iteration, ElementDefinition element)
-        {
-            if (iteration == null)
-            {
-                throw new ArgumentNullException(nameof(iteration));
-            }
-
-            var iterationClone = iteration.Clone(false);
-            iterationClone.TopElement = element;
-
-            return await sessionService.UpdateThing(iteration.Container, iterationClone);
-        }
-
         /// <summary>
         /// Adds a new parameter for a given element definition
         /// </summary>