Index: Ringtoets/Integration/src/Ringtoets.Integration.Service/Merge/AssessmentSectionProviderService.cs
===================================================================
diff -u -rf940039cf98be19f0e419fbb22dd4d17777c89ed -r14739dcebfe29602d6141e045315e9e44269f4b0
--- Ringtoets/Integration/src/Ringtoets.Integration.Service/Merge/AssessmentSectionProviderService.cs	(.../AssessmentSectionProviderService.cs)	(revision f940039cf98be19f0e419fbb22dd4d17777c89ed)
+++ Ringtoets/Integration/src/Ringtoets.Integration.Service/Merge/AssessmentSectionProviderService.cs	(.../AssessmentSectionProviderService.cs)	(revision 14739dcebfe29602d6141e045315e9e44269f4b0)
@@ -45,7 +45,12 @@
                 throw new AssessmentSectionProviderException(exceptionMessage, e);
             }
 
-            return openedProject?.AssessmentSections;
+            if (openedProject == null)
+            {
+                throw new AssessmentSectionProviderException();
+            }
+
+            return openedProject.AssessmentSections;
         }
     }
 }
\ No newline at end of file
Index: Ringtoets/Integration/src/Ringtoets.Integration.Service/Merge/IAssessmentSectionProvider.cs
===================================================================
diff -u -r29d71fc2b326ae60c281103380b4babe1b881f87 -r14739dcebfe29602d6141e045315e9e44269f4b0
--- Ringtoets/Integration/src/Ringtoets.Integration.Service/Merge/IAssessmentSectionProvider.cs	(.../IAssessmentSectionProvider.cs)	(revision 29d71fc2b326ae60c281103380b4babe1b881f87)
+++ Ringtoets/Integration/src/Ringtoets.Integration.Service/Merge/IAssessmentSectionProvider.cs	(.../IAssessmentSectionProvider.cs)	(revision 14739dcebfe29602d6141e045315e9e44269f4b0)
@@ -21,6 +21,7 @@
 
 using System.Collections.Generic;
 using Ringtoets.Integration.Data;
+using Ringtoets.Integration.Service.Exceptions;
 
 namespace Ringtoets.Integration.Service.Merge
 {
@@ -34,6 +35,8 @@
         /// </summary>
         /// <param name="filePath">The file path to read the assessment sections from.</param>
         /// <returns>A collection of <see cref="AssessmentSection"/>.</returns>
+        /// <exception cref="AssessmentSectionProviderException">Thrown if something went wrong
+        /// when providing the assessment sections.</exception>
         IEnumerable<AssessmentSection> GetAssessmentSections(string filePath);
     }
 }
\ No newline at end of file
Index: Ringtoets/Integration/test/Ringtoets.Integration.Service.Test/Merge/AssessmentSectionProviderServiceTest.cs
===================================================================
diff -u -rf940039cf98be19f0e419fbb22dd4d17777c89ed -r14739dcebfe29602d6141e045315e9e44269f4b0
--- Ringtoets/Integration/test/Ringtoets.Integration.Service.Test/Merge/AssessmentSectionProviderServiceTest.cs	(.../AssessmentSectionProviderServiceTest.cs)	(revision f940039cf98be19f0e419fbb22dd4d17777c89ed)
+++ Ringtoets/Integration/test/Ringtoets.Integration.Service.Test/Merge/AssessmentSectionProviderServiceTest.cs	(.../AssessmentSectionProviderServiceTest.cs)	(revision 14739dcebfe29602d6141e045315e9e44269f4b0)
@@ -37,63 +37,85 @@
 
             // Assert
             Assert.IsInstanceOf<IAssessmentSectionProvider>(provider);
+            mocks.VerifyAll();
         }
 
         [Test]
-        public void GetAssessmentSections_LoadingProjectSuccesful_ReturnsRingtoetsProject()
+        public void GetAssessmentSections_Always_SendsFilePathToLoadsProject()
         {
             // Setup
             const string filePath = "Some path";
+
+            var mocks = new MockRepository();
+            var storeProject = mocks.StrictMock<IStoreProject>();
+            storeProject.Expect(sp => sp.LoadProject(filePath)).Return(new RingtoetsProject());
+            mocks.ReplayAll();
+
+            var provider = new AssessmentSectionProviderService(storeProject);
+
+            // Call
+            provider.GetAssessmentSections(filePath);
+
+            // Assert
+            mocks.VerifyAll();
+        }
+
+        [Test]
+        public void GetAssessmentSections_LoadingProjectSuccesful_ReturnsRingtoetsProject()
+        {
+            // Setup
             var project = new RingtoetsProject();
 
             var mocks = new MockRepository();
             var storeProject = mocks.StrictMock<IStoreProject>();
-            storeProject.Expect(sp => sp.LoadProject(filePath)).Return(project);
+            storeProject.Expect(sp => sp.LoadProject(null))
+                        .IgnoreArguments()
+                        .Return(project);
             mocks.ReplayAll();
 
             var provider = new AssessmentSectionProviderService(storeProject);
 
             // Call
-            IEnumerable<AssessmentSection> assessmentSections = provider.GetAssessmentSections(filePath);
+            IEnumerable<AssessmentSection> assessmentSections = provider.GetAssessmentSections(string.Empty);
 
             // Assert
             Assert.AreSame(project.AssessmentSections, assessmentSections);
             mocks.VerifyAll();
         }
 
         [Test]
-        public void GetAssessmentSections_LoadedProjectNull_ReturnsNull()
+        public void GetAssessmentSections_LoadedProjectNull_ThrowsAssessmentSectionProviderException()
         {
             // Setup
-            const string filePath = "Some path";
-
             var mocks = new MockRepository();
             var storeProject = mocks.StrictMock<IStoreProject>();
-            storeProject.Expect(sp => sp.LoadProject(filePath)).Return(null);
+            storeProject.Expect(sp => sp.LoadProject(null))
+                        .IgnoreArguments()
+                        .Return(null);
             mocks.ReplayAll();
 
             var provider = new AssessmentSectionProviderService(storeProject);
 
             // Call
-            IEnumerable<AssessmentSection> assessmentSections = provider.GetAssessmentSections(filePath);
+            TestDelegate call = () => provider.GetAssessmentSections(string.Empty);
 
             // Assert
-            Assert.IsNull(assessmentSections);
+            Assert.Throws<AssessmentSectionProviderException>(call);
             mocks.VerifyAll();
         }
 
         [Test]
         public void GetAssessmentSections_LoadingProjectThrowsException_ThrowsAssessmentSectionProviderExceptionAndLogsError()
         {
             // Setup
-            const string filePath = "Some path";
             const string exceptionMessage = "StorageException";
-
             var storageException = new StorageException(exceptionMessage);
 
             var mocks = new MockRepository();
             var storeProject = mocks.StrictMock<IStoreProject>();
-            storeProject.Expect(sp => sp.LoadProject(filePath)).Throw(storageException);
+            storeProject.Expect(sp => sp.LoadProject(null))
+                        .IgnoreArguments()
+                        .Throw(storageException);
             mocks.ReplayAll();
 
             var provider = new AssessmentSectionProviderService(storeProject);
@@ -105,7 +127,7 @@
             {
                 try
                 {
-                    provider.GetAssessmentSections(filePath);
+                    provider.GetAssessmentSections(string.Empty);
                 }
                 catch (AssessmentSectionProviderException e)
                 {