diff --git a/buildSrc/src/main/groovy/io.micronaut.build.internal.validation-test-suite.gradle b/buildSrc/src/main/groovy/io.micronaut.build.internal.validation-test-suite.gradle
index 7d0268ed..382fe087 100644
--- a/buildSrc/src/main/groovy/io.micronaut.build.internal.validation-test-suite.gradle
+++ b/buildSrc/src/main/groovy/io.micronaut.build.internal.validation-test-suite.gradle
@@ -7,3 +7,7 @@ micronaut {
     // Do not build examples against M1 since the platform is not released
     version = "4.0.0-SNAPSHOT"
 }
+
+tasks.withType(Test).configureEach {
+    useJUnitPlatform()
+}
diff --git a/gradle/libs.versions.toml b/gradle/libs.versions.toml
index d4ec4336..28b78733 100644
--- a/gradle/libs.versions.toml
+++ b/gradle/libs.versions.toml
@@ -29,12 +29,14 @@ jakarta-validation-tck = "3.0.1"
 micronaut-reactor = { module = 'io.micronaut.reactor:micronaut-reactor-bom', version.ref = "micronaut-reactor" }
 micronaut-rxjava2 = { module = 'io.micronaut.rxjava2:micronaut-rxjava2-bom', version.ref = "micronaut-rxjava2" }
 micronaut-kotlin = { module = 'io.micronaut.kotlin:micronaut-kotlin-bom', version.ref = "micronaut-kotlin" }
-micronaut-test-junit5 = { module = "io.micronaut.test:micronaut-test-junit5", version.ref = "micronaut-test" }
+
 groovy-bom = { module = "org.apache.groovy:groovy-bom", version.ref = "groovy" }
 groovy-json = { module = "org.apache.groovy:groovy-json" }
 
 # TESTING
 
+micronaut-test-junit5 = { module = "io.micronaut.test:micronaut-test-junit5", version.ref = "micronaut-test" }
+micronaut-test-spock = { module = "io.micronaut.test:micronaut-test-spock", version.ref = "micronaut-test" }
 junit-jupiter-api = { module = "org.junit.jupiter:junit-jupiter-api", version.ref = "junit5" }
 junit-jupiter-engine = { module = "org.junit.jupiter:junit-jupiter-engine", version.ref = "junit5" }
 kotlin-kotest-junit5 = { module = "io.kotest:kotest-runner-junit5-jvm", version.ref = "kotest" }
diff --git a/test-suite-groovy/build.gradle b/test-suite-groovy/build.gradle
index 9e143ffa..00ee0daa 100644
--- a/test-suite-groovy/build.gradle
+++ b/test-suite-groovy/build.gradle
@@ -1,5 +1,6 @@
 plugins {
     id 'io.micronaut.build.internal.validation-test-suite'
+    id 'groovy'
 }
 
 dependencies {
@@ -12,6 +13,7 @@ dependencies {
     implementation mnReactor.micronaut.reactor
 
     testImplementation project(":validation")
+    testImplementation project(":validation-processor")
     testAnnotationProcessor project(":validation-processor")
     testAnnotationProcessor mn.micronaut.inject.java
     testImplementation libs.spotbugs
@@ -26,8 +28,8 @@ dependencies {
     testImplementation mn.micronaut.inject.java.test
     testImplementation mn.micronaut.jackson.databind
 
-    testImplementation("org.junit.jupiter:junit-jupiter-api")
-    testImplementation("io.micronaut.test:micronaut-test-junit5:3.9.2")
-    testRuntimeOnly("org.junit.jupiter:junit-jupiter-engine:{junitVersion}")
-    testImplementation("org.junit.jupiter:junit-jupiter-engine:{junitVersion}")
+    testImplementation libs.junit.jupiter.api
+    testImplementation libs.micronaut.test.spock
+    testImplementation libs.junit.jupiter.engine
+    testRuntimeOnly libs.junit.jupiter.engine
 }
diff --git a/test-suite/src/test/java/io/micronaut/docs/validation/iterable/BookInfoSpec.java b/test-suite/src/test/java/io/micronaut/docs/validation/iterable/BookInfoSpec.java
index efae047b..a126d94b 100644
--- a/test-suite/src/test/java/io/micronaut/docs/validation/iterable/BookInfoSpec.java
+++ b/test-suite/src/test/java/io/micronaut/docs/validation/iterable/BookInfoSpec.java
@@ -1,12 +1,14 @@
 package io.micronaut.docs.validation.iterable;
 
-import java.util.*;
-
 import io.micronaut.test.extensions.junit5.annotation.MicronautTest;
 import jakarta.inject.Inject;
+import jakarta.validation.ConstraintViolationException;
 import org.junit.jupiter.api.Test;
 
-import jakarta.validation.ConstraintViolationException;
+import java.util.Arrays;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertThrows;
@@ -28,7 +30,7 @@ void testAuthorNamesAreValidated() {
                         bookInfoService.setBookAuthors("My Book", authors)
                 );
 
-        assertEquals("setBookAuthors.authors[1]<E String>: must not be blank",
+        assertEquals("setBookAuthors.authors[1]<list element>: must not be blank",
                 exception.getMessage()); // <1>
     }
 
@@ -42,7 +44,7 @@ void testSectionsAreValidated() {
                         bookInfoService.setBookSectionPages("My Book", sectionStartPages)
                 );
 
-        assertEquals("setBookSectionPages.sectionStartPages[]<K String>: must not be blank",
+        assertEquals("setBookSectionPages.sectionStartPages[]<map key>: must not be blank",
                 exception.getMessage()); // <2>
     }
 
diff --git a/validation/src/main/java/io/micronaut/validation/validator/DefaultConstraintDescriptor.java b/validation/src/main/java/io/micronaut/validation/validator/DefaultConstraintDescriptor.java
index 950c02da..7e1b2a5b 100644
--- a/validation/src/main/java/io/micronaut/validation/validator/DefaultConstraintDescriptor.java
+++ b/validation/src/main/java/io/micronaut/validation/validator/DefaultConstraintDescriptor.java
@@ -152,13 +152,15 @@ public Map<String, Object> getAttributes() {
         for (Map.Entry<?, ?> entry : values.entrySet()) {
             variables.put(entry.getKey().toString(), entry.getValue());
         }
-        final Map<CharSequence, Object> defaultValues = annotationValue.getDefaultValues();
-        for (Map.Entry<CharSequence, Object> entry : defaultValues.entrySet()) {
-            final String n = entry.getKey().toString();
-            if (!variables.containsKey(n)) {
-                final Object v = entry.getValue();
-                if (v != null) {
-                    variables.put(n, v);
+        if (annotationValue.getDefaultValues() != null) {
+            final Map<CharSequence, Object> defaultValues = annotationValue.getDefaultValues();
+            for (Map.Entry<CharSequence, Object> entry : defaultValues.entrySet()) {
+                final String n = entry.getKey().toString();
+                if (!variables.containsKey(n)) {
+                    final Object v = entry.getValue();
+                    if (v != null) {
+                        variables.put(n, v);
+                    }
                 }
             }
         }