Index: Ringtoets/Common/test/Ringtoets.Common.IO.Test/Readers/CombinedXmlSchemaDefinitionTest.cs
===================================================================
diff -u -r85461eb2fda69be38558eb36a0d757fca4ddb125 -rc04a1ae67303b6029fe655a1fc7e57f6509e9a5f
--- Ringtoets/Common/test/Ringtoets.Common.IO.Test/Readers/CombinedXmlSchemaDefinitionTest.cs	(.../CombinedXmlSchemaDefinitionTest.cs)	(revision 85461eb2fda69be38558eb36a0d757fca4ddb125)
+++ Ringtoets/Common/test/Ringtoets.Common.IO.Test/Readers/CombinedXmlSchemaDefinitionTest.cs	(.../CombinedXmlSchemaDefinitionTest.cs)	(revision c04a1ae67303b6029fe655a1fc7e57f6509e9a5f)
@@ -34,6 +34,8 @@
     public class CombinedXmlSchemaDefinitionTest
     {
         private readonly string validMainSchemaDefinition;
+        private readonly string validNestedSchemaDefinition1;
+        private readonly string validNestedSchemaDefinition2;
 
         private readonly string testDirectoryPath = TestHelper.GetTestDataPath(TestDataPath.Ringtoets.Common.IO,
                                                                                "CombinedXmlSchemaDefinition");
@@ -45,7 +47,15 @@
         public void Constructor_EmptyMainSchemaDefinition_ThrowArgumentException(string emptyMainSchemaDefinition)
         {
             // Call
-            TestDelegate call = () => new CombinedXmlSchemaDefinition(emptyMainSchemaDefinition, new Dictionary<string, string>());
+            TestDelegate call = () => new CombinedXmlSchemaDefinition(emptyMainSchemaDefinition, new Dictionary<string, string>
+            {
+                {
+                    "NestedSchemaDefintion1.xsd", validNestedSchemaDefinition1
+                },
+                {
+                    "NestedSchemaDefintion2.xsd", validNestedSchemaDefinition2
+                }
+            });
 
             // Assert
             var exception = Assert.Throws<ArgumentException>(call);
@@ -73,7 +83,10 @@
             TestDelegate call = () => new CombinedXmlSchemaDefinition(validMainSchemaDefinition, new Dictionary<string, string>
             {
                 {
-                    "Test", emptyNestedSchemaDefinition
+                    "NestedSchemaDefintion1.xsd", validNestedSchemaDefinition1
+                },
+                {
+                    "NestedSchemaDefintion2.xsd", emptyNestedSchemaDefinition
                 }
             });
 
@@ -97,7 +110,15 @@
             string xsdPath = Path.Combine(testDirectoryPath, invalidMainSchemaDefinition);
 
             // Call
-            TestDelegate call = () => new CombinedXmlSchemaDefinition(File.ReadAllText(xsdPath), new Dictionary<string, string>());
+            TestDelegate call = () => new CombinedXmlSchemaDefinition(File.ReadAllText(xsdPath), new Dictionary<string, string>
+            {
+                {
+                    "NestedSchemaDefintion1.xsd", validNestedSchemaDefinition1
+                },
+                {
+                    "NestedSchemaDefintion2.xsd", validNestedSchemaDefinition2
+                }
+            });
 
             // Assert
             var exception = Assert.Throws<ArgumentException>(call);
@@ -108,6 +129,8 @@
         public CombinedXmlSchemaDefinitionTest()
         {
             validMainSchemaDefinition = File.ReadAllText(Path.Combine(testDirectoryPath, "validMainSchemaDefinition.xsd"));
+            validNestedSchemaDefinition1 = File.ReadAllText(Path.Combine(testDirectoryPath, "validNestedSchemaDefinition1.xsd"));
+            validNestedSchemaDefinition2 = File.ReadAllText(Path.Combine(testDirectoryPath, "validNestedSchemaDefinition2.xsd"));
         }
     }
 }
\ No newline at end of file
Index: Ringtoets/Common/test/Ringtoets.Common.IO.Test/test-data/CombinedXmlSchemaDefinition/validMainSchemaDefinition.xsd
===================================================================
diff -u -r85461eb2fda69be38558eb36a0d757fca4ddb125 -rc04a1ae67303b6029fe655a1fc7e57f6509e9a5f
--- Ringtoets/Common/test/Ringtoets.Common.IO.Test/test-data/CombinedXmlSchemaDefinition/validMainSchemaDefinition.xsd	(.../validMainSchemaDefinition.xsd)	(revision 85461eb2fda69be38558eb36a0d757fca4ddb125)
+++ Ringtoets/Common/test/Ringtoets.Common.IO.Test/test-data/CombinedXmlSchemaDefinition/validMainSchemaDefinition.xsd	(.../validMainSchemaDefinition.xsd)	(revision c04a1ae67303b6029fe655a1fc7e57f6509e9a5f)
@@ -1,19 +1,19 @@
-<?xml version="1.0" encoding="utf-8"?>
+<?xml version="1.0" encoding="UTF-8"?>
+
 <xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema">
-  <xs:redefine schemaLocation="ConfiguratieSchema.xsd">
-    <xs:complexType name="berekeningType">
+
+  <xs:redefine schemaLocation="NestedSchemaDefinition1.xsd">
+    <xs:complexType name="itemType">
       <xs:complexContent>
-        <xs:extension base="berekeningType">
+        <xs:extension base="itemType">
           <xs:sequence>
-            <xs:element ref="test" minOccurs="0"/>
+              <xs:element ref="genericElement"/>
           </xs:sequence>
         </xs:extension>
       </xs:complexContent>
     </xs:complexType>
   </xs:redefine>
-  <xs:element name="test">
-    <xs:simpleType>
-      <xs:restriction base="xs:double"/>
-    </xs:simpleType>
-  </xs:element>
+
+  <xs:include schemaLocation="NestedSchemaDefinition2.xsd"/>
+
 </xs:schema>
\ No newline at end of file
Index: Ringtoets/Common/test/Ringtoets.Common.IO.Test/test-data/CombinedXmlSchemaDefinition/validNestedSchemaDefinition1.xsd
===================================================================
diff -u
--- Ringtoets/Common/test/Ringtoets.Common.IO.Test/test-data/CombinedXmlSchemaDefinition/validNestedSchemaDefinition1.xsd	(revision 0)
+++ Ringtoets/Common/test/Ringtoets.Common.IO.Test/test-data/CombinedXmlSchemaDefinition/validNestedSchemaDefinition1.xsd	(revision c04a1ae67303b6029fe655a1fc7e57f6509e9a5f)
@@ -0,0 +1,23 @@
+<?xml version="1.0" encoding="utf-8"?>
+
+<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema">
+
+  <xs:element name="container">
+    <xs:complexType>
+      <xs:choice minOccurs="0" maxOccurs="unbounded">
+        <xs:element ref="item"/>
+      </xs:choice>
+    </xs:complexType>
+  </xs:element>
+
+  <xs:element name="item" type="itemType" />
+
+  <xs:complexType name="itemType">
+    <xs:attribute name="naam" use="required">
+      <xs:simpleType>
+        <xs:restriction base="xs:string"/>
+      </xs:simpleType>
+    </xs:attribute>
+  </xs:complexType>
+
+</xs:schema>
\ No newline at end of file
Index: Ringtoets/Common/test/Ringtoets.Common.IO.Test/test-data/CombinedXmlSchemaDefinition/validNestedSchemaDefinition2.xsd
===================================================================
diff -u
--- Ringtoets/Common/test/Ringtoets.Common.IO.Test/test-data/CombinedXmlSchemaDefinition/validNestedSchemaDefinition2.xsd	(revision 0)
+++ Ringtoets/Common/test/Ringtoets.Common.IO.Test/test-data/CombinedXmlSchemaDefinition/validNestedSchemaDefinition2.xsd	(revision c04a1ae67303b6029fe655a1fc7e57f6509e9a5f)
@@ -0,0 +1,13 @@
+<?xml version="1.0" encoding="utf-8"?>
+
+<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema">
+
+  <xs:element name="genericElement">
+    <xs:simpleType>
+      <xs:restriction base="xs:string">
+        <xs:minLength value="1"/>
+      </xs:restriction>
+    </xs:simpleType>
+  </xs:element>
+
+</xs:schema>
\ No newline at end of file