There was a fix made to handle JUnit Assumptions - GRADLE-2454.
Unfortunately it is still not working correctly...

In XML test report that is created by Gradle, it should tot up the number of skipped tests and place it in 'skipped' attribute of the 'testsuite' tag, according to schema. See: http://stackoverflow.com/questions/4922867/junit-xml-format-specification-that-hudson-supports

<xs:element name="testsuite">
<xs:complexType>
<xs:sequence>
...
</xs:sequence>
<xs:attribute name="tests" type="xs:string" use="required"/>
<xs:attribute name="failures" type="xs:string" use="optional"/>
<xs:attribute name="errors" type="xs:string" use="optional"/>
<xs:attribute name="skipped" type="xs:string" use="optional"/>
...

Additionally, ignored tests are marked with weird tag 'ignored-testcase' and again, according to schema, it should be 'skipped' tag inside 'testcase' tag:
<xs:element name="testcase">
<xs:complexType>
<xs:sequence>
<xs:element ref="skipped" minOccurs="0" maxOccurs="1"/>
...
And this is what is actually taken into account by Hudson. Otherwise tools like Hudson don't see any skipped tests during reports/charts generation so the recent fix is not fully functional.