Index: Ringtoets/GrassCoverErosionOutwards/test/Ringtoets.GrassCoverErosionOutwards.Integration.Test/GrassCoverErosionOutwardsWaveConditionsCalculationActivityIntegrationTest.cs
===================================================================
diff -u -r623d00969818278225ff9f2524a4b9e9d3b0b1d8 -r4111bcd2332c3de3de91bd524378ddca18e515d7
--- Ringtoets/GrassCoverErosionOutwards/test/Ringtoets.GrassCoverErosionOutwards.Integration.Test/GrassCoverErosionOutwardsWaveConditionsCalculationActivityIntegrationTest.cs	(.../GrassCoverErosionOutwardsWaveConditionsCalculationActivityIntegrationTest.cs)	(revision 623d00969818278225ff9f2524a4b9e9d3b0b1d8)
+++ Ringtoets/GrassCoverErosionOutwards/test/Ringtoets.GrassCoverErosionOutwards.Integration.Test/GrassCoverErosionOutwardsWaveConditionsCalculationActivityIntegrationTest.cs	(.../GrassCoverErosionOutwardsWaveConditionsCalculationActivityIntegrationTest.cs)	(revision 4111bcd2332c3de3de91bd524378ddca18e515d7)
@@ -23,6 +23,7 @@
 using System.Collections.Generic;
 using System.IO;
 using System.Linq;
+using Core.Common.Base;
 using Core.Common.Base.Data;
 using Core.Common.Base.Service;
 using Core.Common.TestUtil;
@@ -698,6 +699,110 @@
             mockRepository.VerifyAll();
         }
 
+        [Test]
+        [TestCaseSource(typeof(HydraRingCalculatorTestCaseProvider), nameof(HydraRingCalculatorTestCaseProvider.GetCalculatorFailingConditions), new object[]
+        {
+            nameof(Finish_InvalidCalculation_DoesNotSetOutputAndNotifyObservers)
+        })]
+        public void Finish_InvalidCalculation_DoesNotSetOutputAndNotifyObservers(bool endInFailure,
+                                                                                 string lastErrorFileContent)
+        {
+            // Setup
+            var mockRepository = new MockRepository();
+            var observer = mockRepository.StrictMock<IObserver>();
+            observer.Expect(o => o.UpdateObserver());
+
+            var calculator = new TestWaveConditionsCosineCalculator
+            {
+                EndInFailure = endInFailure,
+                LastErrorFileContent = lastErrorFileContent
+            };
+            var calculatorFactory = mockRepository.StrictMock<IHydraRingCalculatorFactory>();
+            calculatorFactory.Expect(cf => cf.CreateWaveConditionsCosineCalculator(testDataPath, string.Empty)).Return(calculator).Repeat.Times(3);
+            mockRepository.ReplayAll();
+
+            AssessmentSectionStub assessmentSection = CreateAssessmentSection();
+            var failureMechanism = new GrassCoverErosionOutwardsFailureMechanism();
+            GrassCoverErosionOutwardsHydraulicBoundaryLocationsTestHelper.SetHydraulicBoundaryLocations(
+                failureMechanism,
+                assessmentSection, new[]
+                {
+                    new TestHydraulicBoundaryLocation()
+                });
+            ConfigureAssessmentSectionWithHydraulicBoundaryOutput(assessmentSection);
+
+            GrassCoverErosionOutwardsWaveConditionsCalculation calculation = CreateValidCalculation(assessmentSection.HydraulicBoundaryDatabase.Locations.First());
+
+            calculation.Attach(observer);
+
+            CalculatableActivity activity = GrassCoverErosionOutwardsCalculationActivityFactory.CreateCalculationActivity(calculation,
+                                                                                                                          failureMechanism,
+                                                                                                                          assessmentSection);
+            using (new HydraRingCalculatorFactoryConfig(calculatorFactory))
+            {
+                activity.Run();
+            }
+
+            // Call
+            activity.Finish();
+
+            // Assert
+            Assert.IsNull(calculation.Output);
+            mockRepository.VerifyAll();
+        }
+
+        [Test]
+        public void Finish_ValidCalculation_SetsOutputAndNotifyObserversOfCalculation()
+        {
+            // Setup
+            var mockRepository = new MockRepository();
+            var observer = mockRepository.StrictMock<IObserver>();
+            observer.Expect(o => o.UpdateObserver());
+
+            var calculatorFactory = mockRepository.StrictMock<IHydraRingCalculatorFactory>();
+            var waveConditionsCosineCalculator = new TestWaveConditionsCosineCalculator
+            {
+                WaveHeight = new Random(39).NextDouble()
+            };
+            calculatorFactory.Expect(cf => cf.CreateWaveConditionsCosineCalculator(testDataPath, string.Empty)).Return(waveConditionsCosineCalculator).Repeat.Times(3);
+            mockRepository.ReplayAll();
+
+            AssessmentSectionStub assessmentSection = CreateAssessmentSection();
+            var failureMechanism = new GrassCoverErosionOutwardsFailureMechanism();
+            GrassCoverErosionOutwardsHydraulicBoundaryLocationsTestHelper.SetHydraulicBoundaryLocations(
+                failureMechanism,
+                assessmentSection, new[]
+                {
+                    new TestHydraulicBoundaryLocation()
+                });
+            ConfigureAssessmentSectionWithHydraulicBoundaryOutput(assessmentSection);
+
+            GrassCoverErosionOutwardsWaveConditionsCalculation calculation = CreateValidCalculation(assessmentSection.HydraulicBoundaryDatabase.Locations.First());
+
+            calculation.Attach(observer);
+
+            CalculatableActivity activity = GrassCoverErosionOutwardsCalculationActivityFactory.CreateCalculationActivity(calculation,
+                                                                                                                          failureMechanism,
+                                                                                                                          assessmentSection);
+            using (new HydraRingCalculatorFactoryConfig(calculatorFactory))
+            {
+                activity.Run();
+            }
+
+            // Call
+            activity.Finish();
+
+            // Assert
+            Assert.IsNotNull(calculation.Output);
+            Assert.AreEqual(3, calculation.Output.Items.Count());
+            foreach (WaveConditionsOutput waveConditionsOutput in calculation.Output.Items)
+            {
+                Assert.AreEqual(waveConditionsCosineCalculator.WaveHeight, waveConditionsOutput.WaveHeight, waveConditionsOutput.WaveHeight.GetAccuracy());
+            }
+
+            mockRepository.VerifyAll();
+        }
+
         private static void ConfigureAssessmentSectionWithHydraulicBoundaryOutput(IAssessmentSection assessmentSection)
         {
             assessmentSection.WaterLevelCalculationsForFactorizedLowerLimitNorm.First().Output = new TestHydraulicBoundaryLocationCalculationOutput(9.3);