lwc-jest v0.4.12 does not seem to be generating accurate results for the conditional truecount / falsecount statements. It add
Expected / desired clover.xml output for default lwc-jest --coverage --reporters=default --reporters=jest-junit
<?xml version="1.0" encoding="UTF-8"?>
<coverage generated="1554241233660" clover="3.2.0">
<project timestamp="1554241233660" name="All files">
<metrics statements="7" coveredstatements="7" conditionals="2" coveredconditionals="2" methods="3" coveredmethods="3" elements="12" coveredelements="12" complexity="0" loc="7" ncloc="7" packages="1" files="1" classes="1">
<file name="navBar.js" path="/home/circleci/foo/force-app/main/default/lwc/navBar/navBar.js">
<metrics statements="7" coveredstatements="7" conditionals="2" coveredconditionals="2" methods="3" coveredmethods="3"/>
<line num="3" count="4" type="stmt"/>
<line num="8" count="2" type="cond" truecount="1" falsecount="1"/>
<line num="9" count="1" type="stmt"/>
<line num="11" count="1" type="stmt"/>
<line num="12" count="1" type="stmt"/>
<line num="14" count="1" type="stmt"/>
<line num="18" count="2" type="stmt"/>
</file>
</metrics>
</project>
</coverage>
https://circleci.com/gh/jfeng-salesforce/lwc-jest-sample/4
<?xml version="1.0" encoding="UTF-8"?>
<coverage generated="1554241233660" clover="3.2.0">
<project timestamp="1554241233660" name="All files">
<metrics statements="7" coveredstatements="7" conditionals="2" coveredconditionals="2" methods="3" coveredmethods="3" elements="12" coveredelements="12" complexity="0" loc="7" ncloc="7" packages="1" files="1" classes="1">
<file name="navBar.js" path="/home/circleci/foo/force-app/main/default/lwc/navBar/navBar.js">
<metrics statements="7" coveredstatements="7" conditionals="2" coveredconditionals="2" methods="3" coveredmethods="3"/>
<line num="3" count="4" type="stmt"/>
<line num="8" count="2" type="cond" truecount="2" falsecount="0"/>
<line num="9" count="1" type="stmt"/>
<line num="11" count="1" type="stmt"/>
<line num="12" count="1" type="stmt"/>
<line num="14" count="1" type="stmt"/>
<line num="18" count="2" type="stmt"/>
</file>
</metrics>
</project>
</coverage>