Using snapshot testing with Jest - Pros and Cons

[einatnielsen]

Cons:

• Failures are hard to understand (It’s often hard to see what changed by looking at the snapshot failure diff)
• We tend to update snapshots without thinking
• Easy to commit snapshots with bugs (since we usually don’t read these files carefully)
• Coupling with low level modules (if you don’t use shallow rendering)
• A false sense of security (Snapshots offer no guarantees that component appearance or behavior is correct)
• FB recommends using more specific assertions than using snapshots here

[MatanBorenkraoutNielsen]

Cons:

• Snapshot testing is actually a big implementation detail. It saves component names, prop names and much more that will probably break on every refactor.
• Snapshot False negatives quickly erode the team's trust in a test to actually find bugs and instead come to be seen as a chore on a checklist, also, most developers will just update the snapshot and get it over with.

Pros:

• Inline snapshot is a good tool, using it to check equality of an object, classes or any small object can be useful and added to the specific test (not added as a different file).