Castor test cases are not reactor friendly. Cannot build from mojo root.

When running the build from the top, the castor tests fail with the following. They appear to be looking for mapping.xml from the root of the build, not of the artifact's project.

[info] Processing /data/users/bravo/projects/open source/codehaus-maven/trunk/mojo/src/test/resources/mapping.xml
[info] XML Schema file "/data/users/bravo/projects/open source/codehaus-maven/trunk/mojo/src/test/resources/mapping.xml" not found .
[info] Processing /data/users/bravo/projects/open source/codehaus-maven/trunk/mojo/src/test/resources/mapping.xml
[info] XML Schema file "/data/users/bravo/projects/open source/codehaus-maven/trunk/mojo/src/test/resources/mapping.xml" not found .
[info] Processing /data/users/bravo/projects/open source/codehaus-maven/trunk/mojo/src/test/resources/mapping.xml
[info] XML Schema file "/data/users/bravo/projects/open source/codehaus-maven/trunk/mojo/src/test/resources/mapping.xml" not found .
[info] Nothing to process - all xsds are up to date
[surefire] Running org.apache.maven.plugins.castor.CodeGeneratorMojoTest
[surefire] Tests run: 11, Failures: 0, Errors: 4, Time elapsed: 0 sec <<<<<<<< FAILURE !!