diff --git a/bundle/pom.xml b/bundle/pom.xml
index f81da0db67..101fa242fa 100644
--- a/bundle/pom.xml
+++ b/bundle/pom.xml
@@ -513,6 +513,11 @@
             <artifactId>mockito-core</artifactId>
             <scope>test</scope>
         </dependency>
+        <dependency>
+            <groupId>org.mockito</groupId>
+            <artifactId>mockito-junit-jupiter</artifactId>
+            <scope>test</scope>
+        </dependency>
         <dependency>
             <groupId>junit-addons</groupId>
             <artifactId>junit-addons</artifactId>
@@ -660,6 +665,20 @@
                 </exclusion>
             </exclusions>
         </dependency>
+        <dependency>
+            <groupId>io.wcm</groupId>
+            <artifactId>io.wcm.testing.aem-mock.junit5</artifactId>
+            <exclusions>
+                <exclusion>
+                    <groupId>org.slf4j</groupId>
+                    <artifactId>slf4j-simple</artifactId>
+                </exclusion>
+                <exclusion>
+                    <groupId>org.apache.jackrabbit</groupId>
+                    <artifactId>oak-jcr</artifactId>
+                </exclusion>
+            </exclusions>
+        </dependency>
         <dependency>
             <groupId>org.apache.sling</groupId>
             <artifactId>org.apache.sling.commons.testing</artifactId>
diff --git a/bundle/src/main/java/com/adobe/acs/commons/mcp/form/FieldsetComponent.java b/bundle/src/main/java/com/adobe/acs/commons/mcp/form/FieldsetComponent.java
index d305f45ffd..547db76558 100644
--- a/bundle/src/main/java/com/adobe/acs/commons/mcp/form/FieldsetComponent.java
+++ b/bundle/src/main/java/com/adobe/acs/commons/mcp/form/FieldsetComponent.java
@@ -41,7 +41,9 @@ public void init() {
 
     @Override
     public Resource buildComponentResource() {
-        getProperties().put(CLASS, getCssClass());
+        if (getCssClass() != null) {
+            getProperties().put(CLASS, getCssClass());
+        }
         return super.buildComponentResource();
     }
 
diff --git a/bundle/src/test/java/com/adobe/acs/commons/mcp/form/FieldsetTest.java b/bundle/src/test/java/com/adobe/acs/commons/mcp/form/FieldsetTest.java
new file mode 100644
index 0000000000..255a5e47a9
--- /dev/null
+++ b/bundle/src/test/java/com/adobe/acs/commons/mcp/form/FieldsetTest.java
@@ -0,0 +1,48 @@
+package com.adobe.acs.commons.mcp.form;
+
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.mockito.Mockito.when;
+
+import java.lang.reflect.Field;
+
+import io.wcm.testing.mock.aem.junit5.AemContext;
+import io.wcm.testing.mock.aem.junit5.AemContextExtension;
+import org.apache.sling.api.resource.Resource;
+import org.apache.sling.api.resource.ValueMap;
+import org.apache.sling.api.scripting.SlingScriptHelper;
+import org.apache.sling.testing.mock.sling.ResourceResolverType;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.extension.ExtendWith;
+import org.mockito.Mock;
+import org.mockito.junit.jupiter.MockitoExtension;
+
+@ExtendWith({MockitoExtension.class, AemContextExtension.class})
+class FieldsetTest {
+
+  private final AemContext ctx = new AemContext(ResourceResolverType.JCR_MOCK);
+
+  @Mock
+  private FormField formField;
+
+  @Mock
+  private SlingScriptHelper slingScriptHelper;
+
+  @BeforeEach
+  public void setup() {
+    ctx.currentResource(ctx.create().resource("/dummy/resource"));
+    when(slingScriptHelper.getRequest()).thenReturn(ctx.request());
+  }
+
+  @Test
+  public void classNotSpecified() {
+    final FieldsetComponent fieldsetComponent = new FieldsetComponent();
+    fieldsetComponent.setup("dummy", null, formField, slingScriptHelper);
+
+    Resource resource = fieldsetComponent.buildComponentResource();
+    ValueMap map = resource.getValueMap();
+
+    System.out.println(map);
+    assertFalse(map.containsKey("class"));
+  }
+}
diff --git a/pom.xml b/pom.xml
index 624ee5d2d8..918b8338b6 100644
--- a/pom.xml
+++ b/pom.xml
@@ -638,6 +638,12 @@ Service-Component: OSGI-INF/*.xml
                 <version>4.11.0</version><!-- >= 5.x requires Java 11 -->
                 <scope>test</scope>
             </dependency>
+            <dependency>
+                <groupId>org.mockito</groupId>
+                <artifactId>mockito-junit-jupiter</artifactId>
+                <version>4.11.0</version><!-- >= 5.x requires Java 11 -->
+                <scope>test</scope>
+            </dependency>
             <dependency>
                 <groupId>org.jacoco</groupId>
                 <artifactId>org.jacoco.agent</artifactId>
@@ -682,6 +688,18 @@ Service-Component: OSGI-INF/*.xml
                     </exclusion>
                 </exclusions>
             </dependency>
+            <dependency>
+                <groupId>io.wcm</groupId>
+                <artifactId>io.wcm.testing.aem-mock.junit5</artifactId>
+                <version>5.1.2</version><!-- newer versions require Java 11, https://github.com/wcm-io/io.wcm.testing.aem-mock/issues/13 -->
+                <scope>test</scope>
+                <exclusions>
+                    <exclusion>
+                        <groupId>org.slf4j</groupId>
+                        <artifactId>slf4j-simple</artifactId>
+                    </exclusion>
+                </exclusions>
+            </dependency>
             <dependency>
                 <groupId>org.skyscreamer</groupId>
                 <artifactId>jsonassert</artifactId>