FitNesse. SuiteAcceptanceTests. SuiteResponderTests. SuiteTestResponders. SuiteExecutionStatusMessages.
DoTest [add child]
Create a simple test page

script Page Builder
line !path classes
line !path fitnesse.jar
line !|fitnesse.testutil.undefined variable: FIXTURE_NAME|
line |blah|
page TestPage

Now run the test page.

Response Requester.
uri valid?
TestPage?responder=test true

Response Examiner.

Check the status message.

Response Examiner.
type pattern matches?
contents <div id="execution-status">.*?undefined variable: EXPECTED_STATUS_MESSAGE.*?</div> true
contents <div id="execution-status">.*?<img.*?src="undefined variable: EXPECTED_ICON_URL".*?/>.*?</div> true