Index: Ringtoets/Piping/test/Ringtoets.Piping.Data.Test/PipingSoilLayerTest.cs
===================================================================
diff -u -r1b6b6e221ac583d9d24ec033972acf73ffe30c56 -r24145cb7feea063e2986e8f4b2270bb2a478b3fd
--- Ringtoets/Piping/test/Ringtoets.Piping.Data.Test/PipingSoilLayerTest.cs	(.../PipingSoilLayerTest.cs)	(revision 1b6b6e221ac583d9d24ec033972acf73ffe30c56)
+++ Ringtoets/Piping/test/Ringtoets.Piping.Data.Test/PipingSoilLayerTest.cs	(.../PipingSoilLayerTest.cs)	(revision 24145cb7feea063e2986e8f4b2270bb2a478b3fd)
@@ -90,14 +90,29 @@
         }
 
         [Test]
+        public void Equals_Null_ReturnsFalse()
+        {
+            // Setup
+            var layer = CreateRandomLayer(21);
+
+            // Call
+            var areEqual = layer.Equals(null);
+
+            // Assert
+            Assert.IsFalse(areEqual);
+        }
+
+        [Test]
         [TestCaseSource(nameof(LayerCombinations))]
         public void Equals_DifferentScenarios_ReturnsExpectedResult(PipingSoilLayer layer, PipingSoilLayer otherLayer, bool expectedEqual)
         {
             // Call
-            var areEqual = layer.Equals(otherLayer);
+            var areEqualOne = layer.Equals(otherLayer);
+            var areEqualTwo = otherLayer.Equals(layer);
 
             // Assert
-            Assert.AreEqual(expectedEqual, areEqual);
+            Assert.AreEqual(expectedEqual, areEqualOne);
+            Assert.AreEqual(expectedEqual, areEqualTwo);
         }
 
         private static TestCaseData[] LayerCombinations()