Index: Ringtoets/Common/test/Ringtoets.Common.Data.Test/Probability/NormProbabilityInputTest.cs
===================================================================
diff -u -rfbbee7721490bed57feff74bd27afc3f5cc46849 -r8047e7fd59525ed424105aaefc4ee88b9ae8def6
--- Ringtoets/Common/test/Ringtoets.Common.Data.Test/Probability/NormProbabilityInputTest.cs	(.../NormProbabilityInputTest.cs)	(revision fbbee7721490bed57feff74bd27afc3f5cc46849)
+++ Ringtoets/Common/test/Ringtoets.Common.Data.Test/Probability/NormProbabilityInputTest.cs	(.../NormProbabilityInputTest.cs)	(revision 8047e7fd59525ed424105aaefc4ee88b9ae8def6)
@@ -37,7 +37,9 @@
             var normProbabilityInput = new NormProbabilityInput();
 
             // Assert
+            Assert.AreEqual(double.NaN, normProbabilityInput.Contribution);
             Assert.AreEqual(2, normProbabilityInput.N);
+            Assert.AreEqual(0, normProbabilityInput.Norm);
         }
 
         [Test]
@@ -60,7 +62,7 @@
         [Test]
         [TestCase(0)]
         [TestCase(21)]
-        public void N_ValueOutsideValidRegion_ThrowsArgumentException(int value)
+        public void N_ValueOutsideValidRegion_ThrowsArgumentOutOfRangeException(int value)
         {
             // Setup
             var normProbabilityInput = new NormProbabilityInput();
@@ -69,7 +71,41 @@
             TestDelegate test = () => normProbabilityInput.N = value;
 
             // Assert
-            TestHelper.AssertThrowsArgumentExceptionAndTestMessage<ArgumentOutOfRangeException>(test, Resources.N_Value_should_be_in_interval_1_20);
+            TestHelper.AssertThrowsArgumentExceptionAndTestMessage<ArgumentOutOfRangeException>(test, 
+                Resources.N_Value_should_be_in_interval_1_20);
         }
+
+        [Test]
+        [TestCase(0)]
+        [TestCase(50)]
+        [TestCase(100)]
+        public void Contribution_ValueInsideValidRegion_DoesNotThrow(int value)
+        {
+            // Setup
+            var normProbabilityInput = new NormProbabilityInput();
+
+            // Call
+            TestDelegate test = () => normProbabilityInput.Contribution = value;
+
+            // Assert
+            Assert.DoesNotThrow(test);
+            Assert.AreEqual(value, normProbabilityInput.Contribution);
+        }
+        
+        [Test]
+        [TestCase(-1)]
+        [TestCase(101)]
+        public void Contribution_ValueOutsideValidRegion_ThrowsArgumentOutOfRangeException(int value)
+        {
+            // Setup
+            var normProbabilityInput = new NormProbabilityInput();
+
+            // Call
+            TestDelegate test = () => normProbabilityInput.Contribution = value;
+
+            // Assert
+            TestHelper.AssertThrowsArgumentExceptionAndTestMessage<ArgumentOutOfRangeException>(test,
+                Resources.Contribution_Value_should_be_in_interval_0_100);
+        }
     }
 }
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