Hello, I have a problem and I hope that you help me

Configuration project:
-STS 2.5.2
-java 1.6
-roo 1.1.1
-postgres 8.4
-windows 7

My database have two tables: worker, company


database instrospect return:

<database name="public">
<option key="includedTables" value="worker,company"/>
<table name="company">
<column name="id" primaryKey="true" required="true" size="10" type="4,serial"/>
<column name="name" primaryKey="false" required="true" size="50" type="12,varchar"/>
<column name="version" primaryKey="false" required="false" size="10" type="4,int4"/>
<foreign-key foreignTable="worker" name="fk_worker_company" onDelete="none" onUpdate="none">
<option key="exported" value="true"/>
<reference foreign="company_id" local="id"/>
</foreign-key>
<unique name="pk_company">
<unique-column name="id"/>
</unique>
<unique name="uq_company_name">
<unique-column name="name"/>
</unique>
</table>
<table name="worker">
<column name="id" primaryKey="true" required="true" size="10" type="4,serial"/>
<column name="name" primaryKey="false" required="true" size="50" type="12,varchar"/>
<column name="company_id" primaryKey="false" required="true" size="10" type="4,int4"/>
<column name="version" primaryKey="false" required="false" size="10" type="4,int4"/>
<foreign-key foreignTable="company" name="fk_worker_company" onDelete="none" onUpdate="none">
<option key="exported" value="false"/>
<reference foreign="id" local="company_id"/>
</foreign-key>
<unique name="pk_worker">
<unique-column name="id"/>
</unique>
</table>
</database>

My problem is: the command perform tests return this:

[INFO] Scanning for projects...
[INFO] ------------------------------------------------------------------------
[INFO] Building companyApp
[INFO] task-segment: [test]
[INFO] ------------------------------------------------------------------------
[INFO] [aspectj:compile {execution: default}]
[INFO] [resources:resources {execution: default-resources}]
[INFO] Using 'UTF-8' encoding to copy filtered resources.
[INFO] Copying 4 resources
[INFO] [compiler:compile {execution: default-compile}]
[INFO] Nothing to compile - all classes are up to date
[INFO] [aspectj:test-compile {execution: default}]
[INFO] [resources:testResources {execution: default-testResources}]
[INFO] Using 'UTF-8' encoding to copy filtered resources.
[INFO] Copying 0 resource
[INFO] [compiler:testCompile {execution: default-testCompile}]
[INFO] Nothing to compile - all classes are up to date
[INFO] [surefire:test {execution: default-test}]
[INFO] Surefire report directory: C:\proyectos\companyApp\target\surefire-reports

-------------------------------------------------------
T E S T S
-------------------------------------------------------
Running company.CompanyIntegrationTest
Tests run: 9, Failures: 0, Errors: 0, Skipped: 0, Time elapsed: 5.047 sec
Running company.WorkerIntegrationTest
2011-02-15 12:58:35,942 [main] ERROR org.hibernate.util.JDBCExceptionReporter - Batch entry 0 insert into public.worker (company_id, name, version, id) values (NULL, 'name_0', '0', '260') was aborted. Call getNextException to see the cause.
2011-02-15 12:58:35,943 [main] ERROR org.hibernate.util.JDBCExceptionReporter - ERROR: el valor null para la columna «company_id» viola la restricción not null
2011-02-15 12:58:35,945 [main] ERROR org.hibernate.event.def.AbstractFlushingEventListe ner - Could not synchronize database state with session
org.hibernate.exception.ConstraintViolationExcepti on: Could not execute JDBC batch update
Tests run: 9, Failures: 0, Errors: 8, Skipped: 0, Time elapsed: 0.36 sec <<< FAILURE!

Results :

Tests in error:
testFlush(company.WorkerIntegrationTest)
testMerge(company.WorkerIntegrationTest)
testPersist(company.WorkerIntegrationTest)
testRemove(company.WorkerIntegrationTest)
testCountWorkers(company.WorkerIntegrationTest)
testFindWorker(company.WorkerIntegrationTest)
testFindAllWorkers(company.WorkerIntegrationTest)
testFindWorkerEntries(company.WorkerIntegrationTes t)

Tests run: 18, Failures: 0, Errors: 8, Skipped: 0

[INFO] ------------------------------------------------------------------------
[ERROR] BUILD FAILURE
[INFO] ------------------------------------------------------------------------
[INFO] There are test failures.

Please refer to C:\proyectos\companyApp\target\surefire-reports for the individual test results.
[INFO] ------------------------------------------------------------------------
[INFO] For more information, run Maven with the -e switch
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 10 seconds
[INFO] Finished at: Tue Feb 15 12:58:36 VET 2011
[INFO] Final Memory: 22M/55M
[INFO] ------------------------------------------------------------------------