When I was inexperienced in Java, I wrote a lot of tests using assert(), rather than using assertEquals().
Revisiting code today, I wanted to update many test suites to use assertEquals(), which requires I flip the expected and actual values around. Too difficult to do quickly by hand, so I used the following regular expression:
Find: assert \((.+)\)\.equals\((.+)\)\);
Replace: assertEquals($2, $1));
It worked like a treat.