ComparePagerTest tests that the correct results are returned for an investigation on the Compare tab in Special:Investigate. Currently we only test scenarios where there is only one target, but ideally we would test cases with multiple targets.

When an investigation contains more than one target, a subquery is performed for each target. If we try to do this from the test, we incur the error:

Error: 1137 Can't reopen table: 'unittest_cu_changes'