Index: Core/Common/src/Core.Common.Base/Plugin/DataItemInfo.cs
===================================================================
diff -u -rd1e069321cba9d3b92f873fdd18e393a20659542 -r3fe1e0bdfa0ff0939bbabbc78386ecc7617c96c4
--- Core/Common/src/Core.Common.Base/Plugin/DataItemInfo.cs	(.../DataItemInfo.cs)	(revision d1e069321cba9d3b92f873fdd18e393a20659542)
+++ Core/Common/src/Core.Common.Base/Plugin/DataItemInfo.cs	(.../DataItemInfo.cs)	(revision 3fe1e0bdfa0ff0939bbabbc78386ecc7617c96c4)
@@ -8,6 +8,12 @@
     /// </summary>
     public class DataItemInfo
     {
+        public DataItemInfo()
+        {
+            Name = "";
+            Category = "";
+        }
+
         /// <summary>
         /// Gets or sets the <see cref="Type"/> of the data to create.
         /// </summary>
@@ -46,6 +52,12 @@
     /// <typeparam name="TValue">The type of data to create.</typeparam>
     public class DataItemInfo<TValue>
     {
+        public DataItemInfo()
+        {
+            Name = "";
+            Category = "";
+        }
+
         /// <summary>
         /// Gets the <see cref="Type"/> of the data to create.
         /// </summary>
Index: Core/Common/src/Core.Common.Base/Service/Activity.cs
===================================================================
diff -u -rcf4f947febf6a8d92379094230ca4bade46a87d0 -r3fe1e0bdfa0ff0939bbabbc78386ecc7617c96c4
--- Core/Common/src/Core.Common.Base/Service/Activity.cs	(.../Activity.cs)	(revision cf4f947febf6a8d92379094230ca4bade46a87d0)
+++ Core/Common/src/Core.Common.Base/Service/Activity.cs	(.../Activity.cs)	(revision 3fe1e0bdfa0ff0939bbabbc78386ecc7617c96c4)
@@ -30,6 +30,7 @@
         /// </summary>
         protected Activity()
         {
+            Name = "";
             State = ActivityState.None;
             LogMessages = new Collection<string>();
         }
Index: Core/Common/test/Core.Common.Base.Test/Plugin/ApplicationCoreTest.cs
===================================================================
diff -u -rad6f88d1d7b21f950588f6109b79fe007aab0c9e -r3fe1e0bdfa0ff0939bbabbc78386ecc7617c96c4
--- Core/Common/test/Core.Common.Base.Test/Plugin/ApplicationCoreTest.cs	(.../ApplicationCoreTest.cs)	(revision ad6f88d1d7b21f950588f6109b79fe007aab0c9e)
+++ Core/Common/test/Core.Common.Base.Test/Plugin/ApplicationCoreTest.cs	(.../ApplicationCoreTest.cs)	(revision 3fe1e0bdfa0ff0939bbabbc78386ecc7617c96c4)
@@ -63,7 +63,9 @@
             applicationCore.AddPlugin(applicationPlugin);
 
             // Assert
-            Assert.AreEqual(1, applicationCore.GetSupportedFileImporters(targetItem).Count());
+            var supportedFileImporters = applicationCore.GetSupportedFileImporters(targetItem).ToArray();
+            Assert.AreEqual(1, supportedFileImporters.Length);
+            Assert.AreSame(fileImporter, supportedFileImporters[0]);
         }
 
         [Test]
@@ -146,10 +148,10 @@
             applicationCore.AddPlugin(applicationPlugin);
 
             // Call
-            var supportedImporters = applicationCore.GetSupportedFileImporters(targetItem).ToList();
+            var supportedImporters = applicationCore.GetSupportedFileImporters(targetItem).ToArray();
 
             // Assert
-            Assert.AreEqual(2, supportedImporters.Count);
+            Assert.AreEqual(2, supportedImporters.Length);
             Assert.AreSame(supportedFileImporter1, supportedImporters[0]);
             Assert.AreSame(supportedFileImporter2, supportedImporters[1]);
         }
@@ -176,11 +178,8 @@
 
             applicationCore.AddPlugin(applicationPlugin);
 
-            // Call
-            var supportedImporters = applicationCore.GetSupportedFileImporters(null).ToList();
-
-            // Assert
-            Assert.AreEqual(0, supportedImporters.Count);
+            // Call / Assert
+            CollectionAssert.IsEmpty(applicationCore.GetSupportedFileImporters(null));
         }
 
         [Test]
@@ -213,10 +212,10 @@
             applicationCore.AddPlugin(applicationPlugin);
 
             // Call
-            var supportedExporters = applicationCore.GetSupportedFileExporters(targetItem).ToList();
+            var supportedExporters = applicationCore.GetSupportedFileExporters(targetItem).ToArray();
 
             // Assert
-            Assert.AreEqual(2, supportedExporters.Count);
+            Assert.AreEqual(2, supportedExporters.Length);
             Assert.AreSame(supportedFileExporter1, supportedExporters[0]);
             Assert.AreSame(supportedFileExporter2, supportedExporters[1]);
         }
@@ -243,11 +242,8 @@
 
             applicationCore.AddPlugin(applicationPlugin);
 
-            // Call
-            var supportedExporters = applicationCore.GetSupportedFileExporters(null).ToList();
-
-            // Assert
-            Assert.AreEqual(0, supportedExporters.Count);
+            // Call / Assert
+            CollectionAssert.IsEmpty(applicationCore.GetSupportedFileExporters(null));
         }
 
         [Test]
@@ -279,10 +275,10 @@
             applicationCore.AddPlugin(applicationPlugin);
 
             // Call
-            var supportedDataItemInfos = applicationCore.GetSupportedDataItemInfos(new object()).ToList();
+            var supportedDataItemInfos = applicationCore.GetSupportedDataItemInfos(new object()).ToArray();
 
             // Assert
-            Assert.AreEqual(1, supportedDataItemInfos.Count);
+            Assert.AreEqual(1, supportedDataItemInfos.Length);
             Assert.AreSame(supportedDataItemInfo, supportedDataItemInfos[0]);
         }
 
@@ -306,11 +302,8 @@
 
             applicationCore.AddPlugin(applicationPlugin);
 
-            // Call
-            var supportedDataItemInfos = applicationCore.GetSupportedDataItemInfos(null).ToList();
-
-            // Assert
-            Assert.AreEqual(0, supportedDataItemInfos.Count);
+            // Call / Assert
+            CollectionAssert.IsEmpty(applicationCore.GetSupportedDataItemInfos(null));
         }
 
         [Test]
Index: Core/Common/test/Core.Common.Base.Test/Plugin/DataItemInfoTest.cs
===================================================================
diff -u -r2d209fab7140dfcd277106ee15a1896234159930 -r3fe1e0bdfa0ff0939bbabbc78386ecc7617c96c4
--- Core/Common/test/Core.Common.Base.Test/Plugin/DataItemInfoTest.cs	(.../DataItemInfoTest.cs)	(revision 2d209fab7140dfcd277106ee15a1896234159930)
+++ Core/Common/test/Core.Common.Base.Test/Plugin/DataItemInfoTest.cs	(.../DataItemInfoTest.cs)	(revision 3fe1e0bdfa0ff0939bbabbc78386ecc7617c96c4)
@@ -15,8 +15,8 @@
 
             // Assert
             Assert.IsNull(dataItemInfo.ValueType);
-            Assert.IsNull(dataItemInfo.Name);
-            Assert.IsNull(dataItemInfo.Category);
+            Assert.AreEqual("", dataItemInfo.Name);
+            Assert.AreEqual("", dataItemInfo.Category);
             Assert.IsNull(dataItemInfo.Image);
             Assert.IsNull(dataItemInfo.AdditionalOwnerCheck);
             Assert.IsNull(dataItemInfo.CreateData);
@@ -30,8 +30,8 @@
 
             // Assert
             Assert.AreEqual(typeof(double), dataItemInfo.ValueType);
-            Assert.IsNull(dataItemInfo.Name);
-            Assert.IsNull(dataItemInfo.Category);
+            Assert.AreEqual("", dataItemInfo.Name);
+            Assert.AreEqual("", dataItemInfo.Category);
             Assert.IsNull(dataItemInfo.Image);
             Assert.IsNull(dataItemInfo.AdditionalOwnerCheck);
             Assert.IsNull(dataItemInfo.CreateData);
Index: Core/Common/test/Core.Common.Base.Test/Service/ActivityTest.cs
===================================================================
diff -u -rd6e6eadf4a2521df75b6d371bacbb181a43058a3 -r3fe1e0bdfa0ff0939bbabbc78386ecc7617c96c4
--- Core/Common/test/Core.Common.Base.Test/Service/ActivityTest.cs	(.../ActivityTest.cs)	(revision d6e6eadf4a2521df75b6d371bacbb181a43058a3)
+++ Core/Common/test/Core.Common.Base.Test/Service/ActivityTest.cs	(.../ActivityTest.cs)	(revision 3fe1e0bdfa0ff0939bbabbc78386ecc7617c96c4)
@@ -15,7 +15,7 @@
             var activity = new SimpleActivity(false, false, false);
 
             // Assert
-            Assert.IsNull(activity.Name);
+            Assert.AreEqual("", activity.Name);
             Assert.AreEqual(ActivityState.None, activity.State);
             Assert.IsNull(activity.ProgressText);
             CollectionAssert.IsEmpty(activity.LogMessages);
@@ -40,16 +40,19 @@
         public void ProgressText_SetValue_ProgressChangedListenersAreNotified()
         {
             // Setup
+            const string someProgress = "Some progress";
+
             var counter = 0;
             var activity = new SimpleActivity(false, false, false);
 
             activity.ProgressChanged += (sender, args) => counter++;
 
             // Call
-            activity.SetProgressText("Some progress");
+            activity.SetProgressText(someProgress);
 
             // Assert
             Assert.AreEqual(1, counter);
+            Assert.AreEqual(someProgress, activity.ProgressText);
         }
 
         [Test]
Index: Ringtoets/Piping/test/Ringtoets.Piping.Service.Test/PipingCalculationActivityTest.cs
===================================================================
diff -u -rd6e6eadf4a2521df75b6d371bacbb181a43058a3 -r3fe1e0bdfa0ff0939bbabbc78386ecc7617c96c4
--- Ringtoets/Piping/test/Ringtoets.Piping.Service.Test/PipingCalculationActivityTest.cs	(.../PipingCalculationActivityTest.cs)	(revision d6e6eadf4a2521df75b6d371bacbb181a43058a3)
+++ Ringtoets/Piping/test/Ringtoets.Piping.Service.Test/PipingCalculationActivityTest.cs	(.../PipingCalculationActivityTest.cs)	(revision 3fe1e0bdfa0ff0939bbabbc78386ecc7617c96c4)
@@ -49,8 +49,8 @@
             // Assert
             TestHelper.AssertLogMessages(call, messages =>
             {
-                var msgs = messages.ToList();
-                Assert.AreEqual(4, msgs.Count);
+                var msgs = messages.ToArray();
+                Assert.AreEqual(4, msgs.Length);
                 StringAssert.StartsWith(String.Format("Validatie van '{0}' gestart om: ", invalidPipingCalculation.Name), msgs[0]);
                 StringAssert.StartsWith("Validatie mislukt: ", msgs[1]);
                 StringAssert.StartsWith("Validatie mislukt: ", msgs[2]);
@@ -76,8 +76,8 @@
             // Assert
             TestHelper.AssertLogMessages(call, messages =>
             {
-                var msgs = messages.ToList();
-                Assert.AreEqual(4, msgs.Count);
+                var msgs = messages.ToArray();
+                Assert.AreEqual(4, msgs.Length);
                 StringAssert.StartsWith(String.Format("Validatie van '{0}' gestart om: ", validPipingCalculation.Name), msgs[0]);
                 StringAssert.StartsWith(String.Format("Validatie van '{0}' beëindigd om: ", validPipingCalculation.Name), msgs[1]);
                 StringAssert.StartsWith(String.Format("Berekening van '{0}' gestart om: ", validPipingCalculation.Name), msgs[2]);