diff --git a/rest/src/test/java/es/uvigo/esei/xcs/rest/OwnerResourceRestTest.java b/rest/src/test/java/es/uvigo/esei/xcs/rest/OwnerResourceRestTest.java
index 9ca0d3abb800df34f9ca806de7c4ab5a87c74137..db7a4b0a364c38494023b1c2680afc71134fa059 100644
--- a/rest/src/test/java/es/uvigo/esei/xcs/rest/OwnerResourceRestTest.java
+++ b/rest/src/test/java/es/uvigo/esei/xcs/rest/OwnerResourceRestTest.java
@@ -188,6 +188,7 @@ public class OwnerResourceRestTest {
 	@CleanupUsingScript({ "cleanup.sql", "cleanup-autoincrement.sql" })
 	public void afterCreateWithPets() {}
 
+	
 	private void testCreateOwner(WebTarget webTarget, Owner newOwner) {
 		testCreateOwner(webTarget, newOwner, newOwner);
 	}
@@ -203,7 +204,6 @@ public class OwnerResourceRestTest {
 	    final Owner owner = responseGet.readEntity(Owner.class);
 		assertThat(owner, is(equalsToOwner(persistentOwner)));
 	}
-
 	
 	
 	@Test @InSequence(30)
diff --git a/rest/src/test/java/es/uvigo/esei/xcs/rest/OwnerResourceUnitTest.java b/rest/src/test/java/es/uvigo/esei/xcs/rest/OwnerResourceUnitTest.java
index d8f00f5061b2b811e18b58eed006b6b4332ed68b..baa5c4a82ec2efc3fba71852c738ae41cde93224 100644
--- a/rest/src/test/java/es/uvigo/esei/xcs/rest/OwnerResourceUnitTest.java
+++ b/rest/src/test/java/es/uvigo/esei/xcs/rest/OwnerResourceUnitTest.java
@@ -4,6 +4,7 @@ import static es.uvigo.esei.xcs.domain.entities.IsEqualsToOwner.containsOwnersIn
 import static es.uvigo.esei.xcs.domain.entities.IsEqualsToOwner.equalsToOwner;
 import static es.uvigo.esei.xcs.domain.entities.OwnersDataset.anyLogin;
 import static es.uvigo.esei.xcs.domain.entities.OwnersDataset.anyOwner;
+import static es.uvigo.esei.xcs.domain.entities.OwnersDataset.existentOwner;
 import static es.uvigo.esei.xcs.domain.entities.OwnersDataset.newOwnerWithFreshPets;
 import static es.uvigo.esei.xcs.domain.entities.OwnersDataset.newOwnerWithPersistentPets;
 import static es.uvigo.esei.xcs.domain.entities.OwnersDataset.owners;
@@ -23,6 +24,7 @@ import static org.junit.Assert.assertThat;
 import java.net.URI;
 import java.util.List;
 
+import javax.persistence.EntityExistsException;
 import javax.ws.rs.core.Response;
 import javax.ws.rs.core.UriBuilder;
 import javax.ws.rs.core.UriInfo;
@@ -157,6 +159,18 @@ public class OwnerResourceUnitTest extends EasyMockSupport {
 		resource.create(null);
 	}
 
+	@Test(expected = IllegalArgumentException.class)
+	public void testCreateExistentOwner() {
+		final Owner existentOwner = existentOwner();
+		
+		expect(facade.create(existentOwner))
+			.andThrow(new EntityExistsException());
+		
+		replayAll();
+		
+		resource.create(existentOwner);
+	}
+
 	@Test
 	public void testUpdate() {
 		final Owner owner = anyOwner();
diff --git a/service/src/test/java/es/uvigo/esei/xcs/service/OwnerServiceIntegrationTest.java b/service/src/test/java/es/uvigo/esei/xcs/service/OwnerServiceIntegrationTest.java
index 767f8db60059986feb86237fd1582d7d755b71d6..d62aeaeb668061b9e766f6989c96a4dc89d33524 100644
--- a/service/src/test/java/es/uvigo/esei/xcs/service/OwnerServiceIntegrationTest.java
+++ b/service/src/test/java/es/uvigo/esei/xcs/service/OwnerServiceIntegrationTest.java
@@ -174,6 +174,12 @@ public class OwnerServiceIntegrationTest {
 		asAdmin.call(() -> facade.create(null));
 	}
 
+	@Test(expected = EJBTransactionRolledbackException.class)
+	@ShouldMatchDataSet("owners.xml")
+	public void testUpdateNull() {
+		asAdmin.run(() -> facade.update(null));
+	}
+
 	@Test
 	@ShouldMatchDataSet("owners-update-password.xml")
 	public void testUpdatePassword() {
diff --git a/service/src/test/java/es/uvigo/esei/xcs/service/PetServiceIntegrationTest.java b/service/src/test/java/es/uvigo/esei/xcs/service/PetServiceIntegrationTest.java
index 4a9a2357149a0e0b92d627424dc46971bdea5a28..3d7c94bf67dbd09b16baee7a1598d8cdc40f876c 100644
--- a/service/src/test/java/es/uvigo/esei/xcs/service/PetServiceIntegrationTest.java
+++ b/service/src/test/java/es/uvigo/esei/xcs/service/PetServiceIntegrationTest.java
@@ -132,14 +132,24 @@ public class PetServiceIntegrationTest {
 		final Owner owner = ownerWithoutPets();
 		principal.setName(owner.getLogin());
 		
-		final Pet pet = newPet();
+		final Pet pet = newPetWithOwner(owner);
 		
 		asOwner.call(() -> facade.create(pet));
 	}
+
+	@Test
+	@ShouldMatchDataSet({ "owners.xml", "owners-create-pet.xml" })
+	public void testCreateNullOwner() {
+		principal.setName(ownerWithoutPets().getLogin());
+		
+		final Pet pet = newPet();
+		
+		asOwner.run(() -> facade.create(pet));
+	}
 	
 	@Test(expected = EJBTransactionRolledbackException.class)
 	@ShouldMatchDataSet({ "owners.xml" })
-	public void testCreateNull() {
+	public void testCreateNullPet() {
 		principal.setName(ownerWithoutPets().getLogin());
 		
 		asOwner.run(() -> facade.create(null));