diff --git a/maven-core/src/main/java/org/apache/maven/project/inheritance/DefaultModelInheritanceAssembler.java b/maven-core/src/main/java/org/apache/maven/project/inheritance/DefaultModelInheritanceAssembler.java
index a60e21ee51..23f1335462 100644
--- a/maven-core/src/main/java/org/apache/maven/project/inheritance/DefaultModelInheritanceAssembler.java
+++ b/maven-core/src/main/java/org/apache/maven/project/inheritance/DefaultModelInheritanceAssembler.java
@@ -1,21 +1,4 @@
 package org.apache.maven.project.inheritance;
-
-/*
- * Copyright 2001-2004 The Apache Software Foundation.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
 import org.apache.maven.model.Dependency;
 import org.apache.maven.model.Model;
 import org.apache.maven.model.Repository;
@@ -160,6 +143,21 @@ public class DefaultModelInheritanceAssembler
                 child.getBuild().setDirectory( parent.getBuild().getDirectory() );
             }
 
+            if ( child.getBuild().getSourceDirectory() == null )
+            {
+                child.getBuild().setSourceDirectory( parent.getBuild().getSourceDirectory() );
+            }
+
+            if ( child.getBuild().getUnitTestSourceDirectory() == null )
+            {
+                child.getBuild().setUnitTestSourceDirectory( parent.getBuild().getUnitTestSourceDirectory() );
+            }
+
+            if ( child.getBuild().getAspectSourceDirectory() == null )
+            {
+                child.getBuild().setAspectSourceDirectory( parent.getBuild().getAspectSourceDirectory() );
+            }
+
             if ( child.getBuild().getOutput() == null )
             {
                 child.getBuild().setOutput( parent.getBuild().getOutput() );
diff --git a/maven-core/src/test/java/org/apache/maven/project/inheritance/DefaultModelInheritanceAssemblerTest.java b/maven-core/src/test/java/org/apache/maven/project/inheritance/DefaultModelInheritanceAssemblerTest.java
new file mode 100644
index 0000000000..43e30f442a
--- /dev/null
+++ b/maven-core/src/test/java/org/apache/maven/project/inheritance/DefaultModelInheritanceAssemblerTest.java
@@ -0,0 +1,59 @@
+/* Created on Aug 23, 2004 */
+package org.apache.maven.project.inheritance;
+
+
+import java.util.Arrays;
+import java.util.List;
+
+import org.apache.maven.model.Build;
+import org.apache.maven.model.Model;
+import org.apache.maven.model.UnitTest;
+import org.apache.maven.project.MavenProject;
+
+import junit.framework.TestCase;
+
+/**
+ * @author jdcasey
+ */
+public class DefaultModelInheritanceAssemblerTest extends TestCase {
+    
+    public void testShouldOverrideUnitTestExcludesOnly() {
+        Model parent = new Model();
+        parent.setGroupId("test");
+        parent.setArtifactId("test");
+        parent.setVersion("0.0");
+        
+        Build parentBuild = new Build();
+        parentBuild.setSourceDirectory("src/main/java");
+        parentBuild.setAspectSourceDirectory("src/main/aspects");
+        parentBuild.setUnitTestSourceDirectory("src/test/java");
+        
+        UnitTest parentUT = new UnitTest();
+        parentUT.setIncludes(Arrays.asList(new String[] {"**/*Test.java"}));
+        parentUT.setExcludes(Arrays.asList(new String[] {"**/*Abstract*.java"}));
+        
+        parentBuild.setUnitTest(parentUT);
+        parent.setBuild(parentBuild);
+        
+        Model child = new Model();
+        
+        Build childBuild = new Build();
+        
+        UnitTest childUT = new UnitTest();
+        parentUT.setExcludes(Arrays.asList(new String[] {"**/*Abstract*.java", "**/*AspectTest.java"}));
+        
+        childBuild.setUnitTest(childUT);
+        child.setBuild(childBuild);
+        
+        ModelInheritanceAssembler assembler = new DefaultModelInheritanceAssembler();
+        assembler.assembleModelInheritance(child, parent);
+        
+        List childExcludesTest = child.getBuild().getUnitTest().getExcludes();
+        assertEquals("source directory should be from parent", "src/main/java", child.getBuild().getSourceDirectory());
+        assertEquals("unit test source directory should be from parent", "src/test/java", child.getBuild().getUnitTestSourceDirectory());
+        assertEquals("aspect source directory should be from parent", "src/main/aspects", child.getBuild().getAspectSourceDirectory());
+        assertTrue("unit test excludes should have **/*AspectTest.java", childExcludesTest.contains("**/*AspectTest.java"));
+        assertTrue("unit test excludes should have **/*Abstract*.java", childExcludesTest.contains("**/*Abstract*.java"));
+    }
+
+}