diff --git a/pom.xml b/pom.xml
index e6318c5..4045d96 100644
--- a/pom.xml
+++ b/pom.xml
@@ -350,6 +350,7 @@
           <includeConstructors>true</includeConstructors>
           <includeDynamicBuilders>true</includeDynamicBuilders>
           <includeAdditionalProperties>true</includeAdditionalProperties>
+          <inclusionLevel>NON_EMPTY</inclusionLevel>
         </configuration>
         <executions>
           <execution>
diff --git a/src/test/java/eu/dissco/backend/TestUtils.java b/src/test/java/eu/dissco/backend/TestUtils.java
index 973dd2a..76a2f02 100644
--- a/src/test/java/eu/dissco/backend/TestUtils.java
+++ b/src/test/java/eu/dissco/backend/TestUtils.java
@@ -132,7 +132,6 @@ private static DigitalSpecimen givenDigitalSpecimen(String id, String physicalId
         .withOdsFdoType(DIGITAL_SPECIMEN_TYPE)
         .withDctermsModified("03/12/2012")
         .withDwcDatasetName("Royal Botanic Garden Edinburgh Herbarium")
-        .withDwcPreparations("")
         .withDctermsLicense("http://creativecommons.org/licenses/by/4.0/legalcode")
         .withOdsSpecimenName(specimenName)
         .withOdsOrganisationID("https://ror.org/0349vqz63")