When reading the generated reports I get the following exception

Recording test results
ERROR: Publisher hudson.tasks.junit.JUnitResultArchiver aborted due to exception
java.lang.NullPointerException
at hudson.tasks.junit.CaseResult.getPackageName(CaseResult.java:289)
at hudson.tasks.junit.TestResult.tally(TestResult.java:578)
at hudson.tasks.junit.JUnitParser$ParseResultCallable.invoke(JUnitParser.java:118)
at hudson.tasks.junit.JUnitParser$ParseResultCallable.invoke(JUnitParser.java:90)
at hudson.FilePath.act(FilePath.java:905)
at hudson.FilePath.act(FilePath.java:878)
at hudson.tasks.junit.JUnitParser.parse(JUnitParser.java:87)
at hudson.tasks.junit.JUnitResultArchiver.parse(JUnitResultArchiver.java:121)
at hudson.tasks.junit.JUnitResultArchiver.perform(JUnitResultArchiver.java:133)
at hudson.tasks.BuildStepMonitor$1.perform(BuildStepMonitor.java:19)
at hudson.model.AbstractBuild$AbstractBuildExecution.perform(AbstractBuild.java:804)
at hudson.model.AbstractBuild$AbstractBuildExecution.performAllBuildSteps(AbstractBuild.java:776)
at hudson.model.Build$BuildExecution.post2(Build.java:183)
at hudson.model.AbstractBuild$AbstractBuildExecution.post(AbstractBuild.java:726)
at hudson.model.Run.execute(Run.java:1618)
at hudson.model.FreeStyleBuild.run(FreeStyleBuild.java:46)
at hudson.model.ResourceController.execute(ResourceController.java:88)
at hudson.model.Executor.run(Executor.java:247)

example xml result:

<?xml version="1.0" encoding="UTF-8"?>
<testsuite name="User with two api keys" tests="1" time="0.409146879" failures="0" errors="0" skipped="0">
<testcase name="User with two api keys #api_key returns the first api key" time="0.408775226">
</testcase>
<system-out>
</system-out>
<system-err>
</system-err>
</testsuite>