testDCOM_BDFG (org.eclipse.cdt.ui.tests.text.doctools.DocCommentHighlightingTest) flaky

[jonahgraham]

The flaky test:

testDCOM_BDFG (org.eclipse.cdt.ui.tests.text.doctools.DocCommentHighlightingTest)

with this output;

expected:<[offset: 149, length: 17, offset: 184, length: 18, offset: 223, length: 16, offset: 241, length: 17, offset: 258, length: 16, offset: 345, length: 16]> but was:<[]>
junit.framework.AssertionFailedError: expected:<[offset: 149, length: 17, offset: 184, length: 18, offset: 223, length: 16, offset: 241, length: 17, offset: 258, length: 16, offset: 345, length: 16]> but was:<[]>
	at org.eclipse.cdt.ui.tests.text.doctools.DocCommentHighlightingTest.testDCOM_BDFG(DocCommentHighlightingTest.java:211)

[i-garrison]

This looks like a race in the test.
Adding a couple of sleeps and stepping through in debugger I seldom reproduce the issue with empty result from findRangesColored() and also managed to get different failure in nearby test testDCOM_B

junit.framework.AssertionFailedError:
    expected:<[offset: 149, length: 17, offset: 345, length: 16]>
     but was:<[offset: 129, length: 18, offset: 328, length: 17]>

[jonahgraham]

Thanks @i-garrison for the investigation.

This is now failing basically all the time on GH Actions. I am now looking at this, either full fix, or apply "flaky" to it.

[jonahgraham]

The key thing is that makes testDCOM_BDFG different from the rest of the tests in DocCommentHighlightingTest is that it is run first. Therefore my guess is that some pre-existing state is not being cleared properly.