[BlackFly]

Depends on what I am trying to achieve.

Most code (especially legacy code) has more branches than typically matter: the majority of branches is error handling or special cases and can be ignored when investigating core functionality. Executing the happy path test case for the functionality I want to extend or bug fix and then stepping through the code with a debugger or manually is my usual mode.

I use IntelliJ myself. Being able to step through with a debugger can be a huge help to show actual implementations used in polymorphic code but few test suites are sophisticated enough to guarantee the possibility. Sometimes I will refactor code simultaneously in order to make it more comprehensible; that obviously requires some tests and experience but if you have the tests take the time to gain the experience and otherwise write the tests! Especially BDD style tests, the kind that survive refactoring.