diff --git a/fd-lang/src/test/java/test/fc/FeatureConfigurationPrettyPrinterTest.java b/fd-lang/src/test/java/test/fc/FeatureConfigurationPrettyPrinterTest.java
index 35925cd..f345a98 100644
--- a/fd-lang/src/test/java/test/fc/FeatureConfigurationPrettyPrinterTest.java
+++ b/fd-lang/src/test/java/test/fc/FeatureConfigurationPrettyPrinterTest.java
@@ -1,6 +1,7 @@
 /* (c) https://github.com/MontiCore/monticore */
 package test.fc;
 
+import com.google.common.base.Verify;
 import de.monticore.featureconfiguration.FeatureConfigurationMill;
 import de.monticore.featureconfiguration._ast.ASTFCCompilationUnit;
 import de.monticore.io.FileReaderWriter;
@@ -25,7 +26,7 @@ public void initMills() {
 
   @Test
   public void testValidFCs() throws IOException{
-    for (File validfd : Objects.requireNonNull(new File("src/test/resources/fcvalid/").listFiles((file, s) -> s.endsWith(".fd")))) {
+    for (File validfd : Verify.verifyNotNull(new File("src/test/resources/fcvalid/").listFiles((file, s) -> s.endsWith(".fd")))) {
       testRoundtripPrint(validfd);
     }
   }
diff --git a/fd-lang/src/test/java/test/fcp/FeatureConfigurationPartialPrettyPrinterTest.java b/fd-lang/src/test/java/test/fcp/FeatureConfigurationPartialPrettyPrinterTest.java
index 4864dba..e74fb71 100644
--- a/fd-lang/src/test/java/test/fcp/FeatureConfigurationPartialPrettyPrinterTest.java
+++ b/fd-lang/src/test/java/test/fcp/FeatureConfigurationPartialPrettyPrinterTest.java
@@ -1,6 +1,7 @@
 /* (c) https://github.com/MontiCore/monticore */
 package test.fcp;
 
+import com.google.common.base.Verify;
 import de.monticore.featureconfiguration._ast.ASTFCCompilationUnit;
 import de.monticore.featureconfigurationpartial.FeatureConfigurationPartialMill;
 import de.monticore.io.FileReaderWriter;
@@ -25,7 +26,7 @@ public void initMills() {
 
   @Test
   public void testValidPFC() throws IOException{
-    for (File validfd : Objects.requireNonNull(new File("src/test/resources/pfcvalid/").listFiles((file, s) -> s.endsWith(".fd")))) {
+    for (File validfd : Verify.verifyNotNull(new File("src/test/resources/pfcvalid/").listFiles((file, s) -> s.endsWith(".fd")))) {
       testRoundtripPrint(validfd);
     }
   }
diff --git a/fd-lang/src/test/java/test/fd/FeatureDiagramPrettyPrinterTest.java b/fd-lang/src/test/java/test/fd/FeatureDiagramPrettyPrinterTest.java
index 4559fbb..833f8a0 100644
--- a/fd-lang/src/test/java/test/fd/FeatureDiagramPrettyPrinterTest.java
+++ b/fd-lang/src/test/java/test/fd/FeatureDiagramPrettyPrinterTest.java
@@ -1,6 +1,7 @@
 /* (c) https://github.com/MontiCore/monticore */
 package test.fd;
 
+import com.google.common.base.Verify;
 import de.monticore.featurediagram.FeatureDiagramMill;
 import de.monticore.featurediagram._ast.ASTFDCompilationUnit;
 import de.monticore.io.FileReaderWriter;
@@ -25,7 +26,7 @@ public void initMills() {
 
   @Test
   public void testValidFDs() throws IOException{
-    for (File validfd : Objects.requireNonNull(new File("src/test/resources/fdvalid/").listFiles((file, s) -> s.endsWith(".fd")))) {
+    for (File validfd : Verify.verifyNotNull(new File("src/test/resources/fdvalid/").listFiles((file, s) -> s.endsWith(".fd")))) {
       testRoundtripPrint(validfd);
     }
   }