Odd error on OS X jenkins box

Hi all, 

I’m getting the following error on a Mac OS X Jenkins box:

http://ci.libreoffice.org/job/lo_gerrit_master/9826/Gerrit=Gerrit,Platform=MacOSX/console 
<http://ci.libreoffice.org/job/lo_gerrit_master/9826/Gerrit=Gerrit,Platform=MacOSX/console>

[build CUT] writerperfect_writer
_RegisterApplication(), FAILED TO establish the default connection to the WindowServer, 
_CGSDefaultConnection() is NULL.
2016-01-03 02:12:14.375 cppunittester[96353:83061014] Couldn't contact spell checker for U.S. 
English
2016-01-03 02:12:16.537 cppunittester[96353:83061045] __agent_connection_block_invoke_2: Connection 
error - Connection invalid
redlineFrame.fodt,fdo69893.odt,fdo70807.odt,fdo75110.odt,fdo75898.odt,shape-textbox.odt,shape-textbox.odt,cp1000071.odt,shape-textbox-vertadjust.odt,shape-textbox-autosize.odt,fdo82191.odt,commented-word.odt,fdo85554.odt,merge-change1.odt,uno-cycle.odt,fdo87448.odt,cp1000115.fodt,tdf90003.odt,tdf83798.odt,tdf90362.fodt,tdf86639.rtf,tdf90883.odt,embedded-data-source.odt,unicodeAltX.odt,draw-anchor-undo.odt,tdf34957.odt,tdf89954.odt,tdf87922.odt,tdf77014.odt,tdf92648.docx,/Users/tdf/lode/jenkins/workspace/lo_gerrit_master/Gerrit/Gerrit/Platform/MacOSX/sw/qa/extras/uiwriter/uiwriter.cxx:2968:SwUiWriterTest::testTdf96536
equality assertion failed
- Expected: 276
- Actual  : 266

/Users/tdf/lode/jenkins/workspace/lo_gerrit_master/Gerrit/Gerrit/Platform/MacOSX/sw/qa/extras/uiwriter/uiwriter.cxx:2968:
 Assertion
Test name: SwUiWriterTest::testTdf96536
equality assertion failed
- Expected: 276
- Actual  : 266

Failures !!!
Run: 83   Failure total: 1   Failures: 1   Errors: 0
2016-01-03 02:12:20.049 cppunittester[96353:83061014] *** -[NSAutoreleasePool release]: This pool 
has already been released, do not drain it (double release).

Error: a unit test failed, please do one of:
make CppunitTest_sw_uiwriter CPPUNITTRACE="lldb --"       # for interactive debugging on OS X
make CppunitTest_sw_uiwriter VALGRIND=memcheck            # for memory checking

/Users/tdf/lode/jenkins/workspace/lo_gerrit_master/Gerrit/Gerrit/Platform/MacOSX/solenv/gbuild/CppunitTest.mk:90:
 recipe for target 
'/Users/tdf/lode/jenkins/workspace/lo_gerrit_master/Gerrit/Gerrit/Platform/MacOSX/workdir/CppunitTest/sw_uiwriter.test'
 failed
make[1]: *** 
[/Users/tdf/lode/jenkins/workspace/lo_gerrit_master/Gerrit/Gerrit/Platform/MacOSX/workdir/CppunitTest/sw_uiwriter.test]
 Error 1
make[1]: *** Waiting for unfinished jobs....
Makefile:247: recipe for target 'build' failed
make: *** [build] Error 2
Build step 'Execute shell' marked build as failure
Finished: FAILURE

Does anyone know what this is all about? Is this environmental? I can’t see how my code would cause 
this!!!

Chris