How do you catch silent logic breaks before committing?

Git is a lifesaver but checking massive diffs after every AI prompt gets exhausting real fast. A lot of times the AI introduces subtle bugs that still compile fine, so tests don't catch them immediately.

Writing a quick automated test before asking the AI to add a new feature has saved me so many times because the test instantly fails if it messes up existing code.

Do you rely on unit tests or just manually review every single line in the diff view?