The formatting-preservation-test.rkt file contains a handful of test cases that check that various Resyntax rules don't reformat more code than expected. But those sorts of tests are also spread across the rest of Resyntax's test suite, alongside other tests for the rule in question. Since this behavior is (mostly) up to the rule to handle correctly, it would make more sense for the tests in formatting-preservation-test.rkt to be moved to the existing rule-specific test files.