diff --git a/maven-project/src/test/java/org/apache/maven/project/PomConstructionTest.java b/maven-project/src/test/java/org/apache/maven/project/PomConstructionTest.java
index bcdd728342..84cb54b97d 100644
--- a/maven-project/src/test/java/org/apache/maven/project/PomConstructionTest.java
+++ b/maven-project/src/test/java/org/apache/maven/project/PomConstructionTest.java
@@ -1117,6 +1117,11 @@ public void testCompleteModel()
         assertEquals( 1, ( (List<?>) pom.getValue( "build/testResources[1]/excludes" ) ).size() );
         assertPathSuffixEquals( "test.excluded", pom.getValue( "build/testResources[1]/excludes[1]" ) );
 
+        assertEquals( 1, ( (List<?>) pom.getValue( "build/extensions" ) ).size() );
+        assertEquals( "org.apache.maven.its.ext", pom.getValue( "build/extensions[1]/groupId" ) );
+        assertEquals( "ext", pom.getValue( "build/extensions[1]/artifactId" ) );
+        assertEquals( "3.0", pom.getValue( "build/extensions[1]/version" ) );
+
         assertEquals( 1, ( (List<?>) pom.getValue( "build/plugins" ) ).size() );
         assertEquals( "org.apache.maven.its.plugins", pom.getValue( "build/plugins[1]/groupId" ) );
         assertEquals( "maven-it-plugin-build", pom.getValue( "build/plugins[1]/artifactId" ) );
diff --git a/maven-project/src/test/resources-project-builder/complete-model/pom.xml b/maven-project/src/test/resources-project-builder/complete-model/pom.xml
index 40cd574410..72dd787276 100644
--- a/maven-project/src/test/resources-project-builder/complete-model/pom.xml
+++ b/maven-project/src/test/resources-project-builder/complete-model/pom.xml
@@ -200,6 +200,14 @@ under the License.
   </repositories>
 
   <build>
+    <extensions>
+      <extension>
+        <groupId>org.apache.maven.its.ext</groupId>
+        <artifactId>ext</artifactId>
+        <version>3.0</version>
+      </extension>
+    </extensions>
+
     <defaultGoal>test</defaultGoal>
     <directory>build</directory>
     <sourceDirectory>sources/main</sourceDirectory>