Tried posting this in the FlashBuilder forum, but got no responses... so posting here in hope of better luck.
I've been using the UIImpersonator in FlexUnit (for AS, not Flex) to unit test certain components that need to be added to the stage to function correctly. To do so, one must initialize the FlexUnitCore.visualDisplayRoot with the stage, which I do when I hand craft the test runner in my own source code.
In FlashBuilder, the test program runner is auto generated by the builder and it uses something called flexunit.flexui.FlexUnitTestRunnerUIAS, for which I cannot find any documentation or source code in the FlexUnit depot. I suspect this is some Flash Builder custom file? In any event, it appears to add itself to the stage, but it seems to not be internally initializing the UIImpersonator correctly. Any DisplayObjects that are added to the UIImpersonator are *not* on the stage.
Has anyone investigated how to make this work correctly? Seems like a bug.
Richard