c++ code:
SUITE( MyTestSuite )
{
bool MyFun()

{ return false; }

TEST( TestSomeStuff )

{ CHECK( MyFun() ); CHECK( MyFun() ); }

}

produces this xml file:
<?xml version="1.0"?>
<unittest-results tests="1" failedtests="1" failures="2" time="0">
<test suite="MyTestSuite" name="TestSomeStuff" time="0">
<failure message="/data/test.cpp(14) : MyFun()"/>
<failure message="/data/test.cpp(15) : MyFun()"/>
</test>
</unittest-results>

reported error:
[xUnit] [ERROR] - At line 5 of file:/d:/.hudson/jobs/***/UnitTest/TEST--615512892.xml:cvc-complex-type.2.4.a: Invalid content was found starting with element 'failure'. One of '

{system-out, system-err}

' is expected.
[xUnit] [WARNING] - The converted file for the result file 'd:\.hudson\jobs***\test_vcproj2cmake_testresults.xml' (during conversion process for the metric 'UnitTest-1.4 (default)') is not valid. The report file has been skipped.

however, removing one line makes it work:
<?xml version="1.0"?>
<unittest-results tests="1" failedtests="1" failures="1" time="0">
<test suite="MyTestSuite" name="TestSomeStuff" time="0">
<failure message="/data/test.cpp(14) : MyFun()"/>
</test>
</unittest-results>