We run Hudson slaves as services via the new WMI support that was added in
Hudson 1.304. This causes a reproduceable problem with using the SeleniumHQ
plugin though. Thankfully this problem is very easy to reproduce.

First, a little background.

In order to have Windows services be able to interact with the desktop, they
need to run as the System account. Since the System account has no user profile
(which Selenium RC wants), it is necessary to use something like SysInternals
psexec utility which can run a process as a different user. This allows us to
launch Selenium RC as a proper user account and then tests run properly.

However, this means that we can not use the SeleniumHQ htmlSuite build step
because of the need to wrap the launch command. Instead we have to create a
build step of Windows batch so that we can invoke the psexec wrapper.

After the test result is generated though, we get a null pointer exception when
trying to publish the test result. Here is the stack trace from the log. The
test result file has been generated properly at this point, and the "Publish
Selenium Report" config is properly referencing the correct file name.

Publishing Selenium report...
FATAL: null
java.lang.NullPointerException
at
hudson.plugins.seleniumhq.SeleniumhqPublisher.perform(SeleniumhqPublisher.java:117)
at
hudson.model.AbstractBuild$AbstractRunner.performAllBuildStep(AbstractBuild.java:372)
at
hudson.model.AbstractBuild$AbstractRunner.performAllBuildStep(AbstractBuild.java:360)
at hudson.model.Build$RunnerImpl.post2(Build.java:183)
at hudson.model.AbstractBuild$AbstractRunner.post(AbstractBuild.java:345)
at hudson.model.Run.run(Run.java:943)
at hudson.model.Build.run(Build.java:112)
at hudson.model.ResourceController.execute(ResourceController.java:93)
at hudson.model.Executor.run(Executor.java:119)

From a quick glance at the source code it looks like the plugin is expecting
that the test result is always generated by the SeleniumHQ build step.

Note that this can be reproduced by creating a job with a Windows batch build
step that consists of one line that will create the result file to be published
from an existing result file.

type path\to\existing\result.html > expected\result.html