diff --git a/src/test/java/org/gcube/informationsystem/impl/properties/EncryptedTest.java b/src/test/java/org/gcube/informationsystem/impl/properties/EncryptedTest.java
index 5d3f23c..943e9f2 100644
--- a/src/test/java/org/gcube/informationsystem/impl/properties/EncryptedTest.java
+++ b/src/test/java/org/gcube/informationsystem/impl/properties/EncryptedTest.java
@@ -60,6 +60,7 @@ public class EncryptedTest extends ContextTest {
 	@Test
 	public void testEncryptedClass() throws Exception {
 		String value = "myValue";
+		String encryptedValue = EncryptedImpl.encrypt(value);
 		
 		Encrypted encrypted = new EncryptedImpl();
 		encrypted.setEncryptedValue(EncryptedImpl.encrypt(value));
@@ -67,10 +68,21 @@ public class EncryptedTest extends ContextTest {
 		String json = ElementMapper.marshal(encrypted);
 		logger.debug(json);
 		
-		Encrypted unmarshalled = ElementMapper.unmarshal(Encrypted.class, json);
-		String decrypted = EncryptedImpl.decrypt(unmarshalled.getEncryptedValue());
+		Property property = ElementMapper.unmarshal(Property.class, json);
+		Assert.assertTrue(property instanceof Encrypted);
+		Assert.assertTrue(((Encrypted) property).getEncryptedValue().compareTo(encryptedValue)==0);
+		String decryptedValue = EncryptedImpl.decrypt(((Encrypted) property).getEncryptedValue());
+		Assert.assertTrue(decryptedValue.compareTo(value)==0);
+		logger.debug(ElementMapper.marshal(property));
+		
+		
+		encrypted = ElementMapper.unmarshal(Encrypted.class, json);
+		Assert.assertTrue(property instanceof Encrypted);
+		Assert.assertTrue(encrypted.getEncryptedValue().compareTo(encryptedValue)==0);
+		decryptedValue = EncryptedImpl.decrypt(((Encrypted) property).getEncryptedValue());
+		Assert.assertTrue(decryptedValue.compareTo(value)==0);
+		logger.debug(ElementMapper.marshal(encrypted));
 		
-		Assert.assertTrue(decrypted.compareTo(value)==0);
 	}
 	
 	@Test
@@ -87,9 +99,14 @@ public class EncryptedTest extends ContextTest {
 		String marshalled = "{\"" + Element.CLASS_PROPERTY + "\":\"MyEncrypted\",\"" + Element.SUPERCLASSES_PROPERTY + "\":[\"" + Encrypted.NAME + "\", \"" + Property.NAME + "\"],\"" + Encrypted.VALUE + "\":\""+ encryptedValue + "\"}";
 		Property property = ElementMapper.unmarshal(Property.class, marshalled);
 		Assert.assertTrue(property instanceof Encrypted);
-		Encrypted encrypted = (Encrypted) property;
-		Assert.assertTrue(encrypted.getEncryptedValue().compareTo(encryptedValue)==0);
+		Assert.assertTrue(((Encrypted) property).getEncryptedValue().compareTo(encryptedValue)==0);
 		logger.debug(ElementMapper.marshal(property));
+		
+		Encrypted encrypted = ElementMapper.unmarshal(Encrypted.class, marshalled);
+		Assert.assertTrue(property instanceof Encrypted);
+		Assert.assertTrue(encrypted.getEncryptedValue().compareTo(encryptedValue)==0);
+		logger.debug(ElementMapper.marshal(encrypted));
+		
 	}
 	
 	@Test
diff --git a/src/test/java/org/gcube/informationsystem/model/impl/properties/HeaderTest.java b/src/test/java/org/gcube/informationsystem/model/impl/properties/HeaderTest.java
index 332bde1..51f818a 100644
--- a/src/test/java/org/gcube/informationsystem/model/impl/properties/HeaderTest.java
+++ b/src/test/java/org/gcube/informationsystem/model/impl/properties/HeaderTest.java
@@ -4,8 +4,8 @@ import java.util.Calendar;
 import java.util.Date;
 import java.util.UUID;
 
-import org.gcube.informationsystem.model.impl.properties.HeaderImpl;
 import org.gcube.informationsystem.model.reference.properties.Header;
+import org.gcube.informationsystem.model.reference.properties.Property;
 import org.gcube.informationsystem.utils.ElementMapper;
 import org.junit.Assert;
 import org.junit.Test;
@@ -27,11 +27,18 @@ public class HeaderTest {
 		String json = ElementMapper.marshal(header);
 		logger.debug(json);
 		
-		Header h = ElementMapper.unmarshal(Header.class, json);
 		
+		Property property = ElementMapper.unmarshal(Property.class, json);
+		Assert.assertTrue(property instanceof Header);
+		Assert.assertTrue(((Header) property).getCreationTime().compareTo(date)==0);
+		Assert.assertTrue(((Header) property).getLastUpdateTime().compareTo(date)==0);
+		logger.debug(ElementMapper.marshal(property));
+		
+		Header h  = ElementMapper.unmarshal(Header.class, json);
+		Assert.assertTrue(property instanceof Header);
 		Assert.assertTrue(h.getCreationTime().compareTo(date)==0);
 		Assert.assertTrue(h.getLastUpdateTime().compareTo(date)==0);
-		
+		logger.debug(ElementMapper.marshal(h));
 	}
 
 }
diff --git a/src/test/java/org/gcube/informationsystem/types/SerializationTest.java b/src/test/java/org/gcube/informationsystem/types/SerializationTest.java
index 3ffc83e..053733a 100644
--- a/src/test/java/org/gcube/informationsystem/types/SerializationTest.java
+++ b/src/test/java/org/gcube/informationsystem/types/SerializationTest.java
@@ -20,19 +20,18 @@ import org.gcube.informationsystem.model.reference.relations.Relation;
 import org.gcube.informationsystem.types.reference.entities.EntityType;
 import org.gcube.informationsystem.types.reference.entities.FacetType;
 import org.gcube.informationsystem.types.reference.entities.ResourceType;
+import org.gcube.informationsystem.types.reference.properties.LinkedEntity;
 import org.gcube.informationsystem.types.reference.properties.PropertyDefinition;
 import org.gcube.informationsystem.types.reference.properties.PropertyType;
-import org.gcube.informationsystem.types.reference.properties.LinkedEntity;
 import org.gcube.informationsystem.types.reference.relations.ConsistsOfType;
 import org.gcube.informationsystem.types.reference.relations.IsRelatedToType;
 import org.gcube.informationsystem.types.reference.relations.RelationType;
 import org.gcube.informationsystem.utils.ElementMapper;
+import org.junit.Assert;
 import org.junit.Test;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
-import com.fasterxml.jackson.databind.ObjectMapper;
-
 public class SerializationTest {
 
 	private static Logger logger = LoggerFactory.getLogger(SerializationTest.class);
@@ -161,12 +160,15 @@ public class SerializationTest {
 		PropagationConstraint propagationConstraint = new PropagationConstraintImpl();
 		propagationConstraint.setAddConstraint(AddConstraint.propagate);
 		propagationConstraint.setRemoveConstraint(RemoveConstraint.cascadeWhenOrphan);
-		
 		String pg = ElementMapper.marshal(propagationConstraint);
 		
-		PropagationConstraint pgUnm  = ElementMapper.unmarshal(PropagationConstraint.class, pg);
+		Property property = ElementMapper.unmarshal(Property.class, pg);
+		Assert.assertTrue(property instanceof PropagationConstraint);
+		logger.debug(ElementMapper.marshal(property));
 		
-		logger.debug("{}", pgUnm);
+		PropagationConstraint pgUnm  = ElementMapper.unmarshal(PropagationConstraint.class, pg);
+		Assert.assertTrue(property instanceof PropagationConstraint);
+		logger.debug(ElementMapper.marshal(pgUnm));
 	}
 	
 	@Test