diff --git a/src/main/java/it/aboutbits/springboot/testing/testdata/base/ModifyableTestDataCreator.java b/src/main/java/it/aboutbits/springboot/testing/testdata/base/ModifiableTestDataCreator.java
similarity index 93%
rename from src/main/java/it/aboutbits/springboot/testing/testdata/base/ModifyableTestDataCreator.java
rename to src/main/java/it/aboutbits/springboot/testing/testdata/base/ModifiableTestDataCreator.java
index a959563..d945982 100644
--- a/src/main/java/it/aboutbits/springboot/testing/testdata/base/ModifyableTestDataCreator.java
+++ b/src/main/java/it/aboutbits/springboot/testing/testdata/base/ModifiableTestDataCreator.java
@@ -12,7 +12,7 @@
 
 @SuppressWarnings("unchecked")
 @Slf4j
-public abstract class ModifyableTestDataCreator<CREATOR extends ModifyableTestDataCreator<CREATOR, ITEM, PARAMETER>, ITEM, PARAMETER> extends TestDataCreator<ITEM> {
+public abstract class ModifiableTestDataCreator<CREATOR extends ModifiableTestDataCreator<CREATOR, ITEM, PARAMETER>, ITEM, PARAMETER> extends TestDataCreator<ITEM> {
     protected static final FakerExtended FAKER = new FakerExtended();
 
     private boolean mutatorSet = false;
@@ -25,7 +25,7 @@ public abstract class ModifyableTestDataCreator<CREATOR extends ModifyableTestDa
     protected ObjIntConsumer<ITEM> resultMutator = (item, index) -> {
     };
 
-    protected ModifyableTestDataCreator(int count) {
+    protected ModifiableTestDataCreator(int count) {
         super(count);
     }
 
diff --git a/src/main/java/it/aboutbits/springboot/testing/validation/core/RuleValidator.java b/src/main/java/it/aboutbits/springboot/testing/validation/core/RuleValidator.java
index 9a4a3da..7e7b16f 100644
--- a/src/main/java/it/aboutbits/springboot/testing/validation/core/RuleValidator.java
+++ b/src/main/java/it/aboutbits/springboot/testing/validation/core/RuleValidator.java
@@ -117,9 +117,19 @@ private static <P> void assertThatValidationIsCompliantForEachProperty(
                     var violations = validator.validate(copy);
 
                     // Check if there are any violations
+                    var violatingFieldMessages = violations
+                            .stream()
+                            .map(violation ->
+                                         "%s => %s".formatted(
+                                                 violation.getPropertyPath().toString(),
+                                                 violation.getMessage()
+                                         )
+                            );
+
                     assertThat(violations)
                             .withFailMessage(
-                                    "More than one property failed to validate during mutation. The supplied parameter possibly contains invalid values."
+                                    "More than one property failed to validate during mutation. The supplied parameter possibly contains invalid values: %s",
+                                    violatingFieldMessages.collect(Collectors.joining(" | "))
                             )
                             .hasSizeLessThan(2);
 
diff --git a/src/main/java/it/aboutbits/springboot/testing/validation/rule/NotBlankRule.java b/src/main/java/it/aboutbits/springboot/testing/validation/rule/NotBlankRule.java
index 052cbb3..8914566 100644
--- a/src/main/java/it/aboutbits/springboot/testing/validation/rule/NotBlankRule.java
+++ b/src/main/java/it/aboutbits/springboot/testing/validation/rule/NotBlankRule.java
@@ -4,6 +4,7 @@
 import it.aboutbits.springboot.testing.validation.core.Rule;
 import it.aboutbits.springboot.testing.validation.core.ValidationRulesData;
 import it.aboutbits.springboot.testing.validation.source.BlankValueSource;
+import it.aboutbits.springboot.testing.validation.source.NullValueSource;
 import lombok.NonNull;
 
 @SuppressWarnings("unchecked")
@@ -12,6 +13,9 @@ default V notBlank(@NonNull String property) {
         addRule(
                 new Rule(property, BlankValueSource.class)
         );
+        addRule(
+                new Rule(property, NullValueSource.class)
+        );
         return (V) this;
     }
 }
diff --git a/src/main/java/it/aboutbits/springboot/testing/validation/rule/NotEmptyRule.java b/src/main/java/it/aboutbits/springboot/testing/validation/rule/NotEmptyRule.java
index 53ba30d..b95bd7a 100644
--- a/src/main/java/it/aboutbits/springboot/testing/validation/rule/NotEmptyRule.java
+++ b/src/main/java/it/aboutbits/springboot/testing/validation/rule/NotEmptyRule.java
@@ -4,6 +4,7 @@
 import it.aboutbits.springboot.testing.validation.core.Rule;
 import it.aboutbits.springboot.testing.validation.core.ValidationRulesData;
 import it.aboutbits.springboot.testing.validation.source.EmptyValueSource;
+import it.aboutbits.springboot.testing.validation.source.NullValueSource;
 import lombok.NonNull;
 
 @SuppressWarnings("unchecked")
@@ -12,6 +13,9 @@ default V notEmpty(@NonNull String property) {
         addRule(
                 new Rule(property, EmptyValueSource.class)
         );
+        addRule(
+                new Rule(property, NullValueSource.class)
+        );
         return (V) this;
     }
 }