Effectively, if you're going to attempt to detect bias, you have to handle the Paradox of Tolerance. Otherwise, for instance, efforts to detect intolerance will be accused of being biased against intolerance, and people who wish to remain intolerant will push you to "fix" it.

Another test case: test to ensure your detector does not detect factual information on evolution or climate change as being "biased" because there's a "side" that denies their existence. Not all "sides" are valid.