If name of package or class contains space or parentheses then it cannot be expanded in report generated by Test Results Analyzer plugin.
See following example of junitResult.xml:
<?xml version='1.0' encoding='UTF-8'?>
<result plugin="junit@1.2-beta-4">
<suites>
<suite>
<file>some.xml</file>
<name>Tests</name>
<stdout></stdout>
<duration>0</duration>
<cases>
<case>
<duration>0</duration>
<className>ExampleClass1</className>
<testName>Example1</testName>
<skipped>true</skipped>
<stdout></stdout>
<failedSince>0</failedSince>
</case>
<case>
<duration>0</duration>
<className>SomePackage.Example Class</className>
<testName>Example2</testName>
<skipped>true</skipped>
<stdout></stdout>
<failedSince>0</failedSince>
</case>
</cases>
</suite>
</suites>
<duration>0</duration>
<keepLongStdio>false</keepLongStdio>
</result>

In this example package name for test "Example1" is missing so Jenkins will show "(root)" and because it contains parentheses cannot be expanded in report.
Similar is for "Example2" for which class name contains space.