Index: Ringtoets/Common/test/Ringtoets.Common.Service.Test/DesignWaterLevelCalculationServiceTest.cs
===================================================================
diff -u -r736f04ea6f24399148ab8efd7f3b03ae8f8f56b5 -r7044ef7d789aec3c3d9dd2c6f38b3699bea0444b
--- Ringtoets/Common/test/Ringtoets.Common.Service.Test/DesignWaterLevelCalculationServiceTest.cs	(.../DesignWaterLevelCalculationServiceTest.cs)	(revision 736f04ea6f24399148ab8efd7f3b03ae8f8f56b5)
+++ Ringtoets/Common/test/Ringtoets.Common.Service.Test/DesignWaterLevelCalculationServiceTest.cs	(.../DesignWaterLevelCalculationServiceTest.cs)	(revision 7044ef7d789aec3c3d9dd2c6f38b3699bea0444b)
@@ -176,7 +176,7 @@
 
                 // Assert
                 AssessmentLevelCalculationInput expectedInput = CreateInput(hydraulicBoundaryLocation, norm);
-                AssertInput(expectedInput, calculator.ReceivedInputs.First());
+                AssertInput(expectedInput, calculator.ReceivedInputs.Single());
                 Assert.IsFalse(calculator.IsCanceled);
             }
             mockRepository.VerifyAll();