Test can be reproduced and successfully passed manually but when executing it, it fails. Error is:

projectMatrixAuth(plugins.MatrixAuthPluginTest)  Time elapsed: 56.977 sec  <<< FAILURE!
java.lang.AssertionError: null
	at org.junit.Assert.fail(Assert.java:86)
	at org.junit.Assert.assertTrue(Assert.java:41)
	at org.junit.Assert.assertNotNull(Assert.java:621)
	at org.junit.Assert.assertNotNull(Assert.java:631)
	at plugins.MatrixAuthPluginTest.projectMatrixAuth(MatrixAuthPluginTest.java:110)`

Other times we got a TimeoutException in org.jenkinsci.test.acceptance.po.create

After some investigation it seems related to jobs not being able to be created due to the OK button not being yet enabled after selecting the job type in the job creation page.

Also some problems arises because jobs are not yet loaded after login and check for existence in the test