Mock vs Spy in Testing with Jest: Which is Better?

In this video, we explore the differences between mocks and spies in testing with Jest. We'll dive into the benefits and drawbacks of each approach, and help you determine which one is best for your specific use case. Whether you're a seasoned developer or just starting out with Jest testing, this video is a must-watch. Join us as we explore the world of Jest testing and help you become a better developer.
Link to the Code example: github.com/mohokh67/jest-mock...
Jest Mock: jestjs.io/docs/mock-functions
Jest Spy: jestjs.io/docs/jest-object#je...
Chapters:
0:00 - intro
2:58 - Write tests
5:30 - Write mocks in jest
11:27 - Write spy in jest
20:58 Mock and Spy comparison

[@Romul3003]

Great tutorial, terrible editor fonts, my eyes are bleeding

[@scally9341]

^

[@dev.channel]

Thanks for the feedback. I will not use this font in future videos

[@edwarddemesaify]

Excellent tutorial... Thank you!

[@sandyrubybassi3462]

Best explanation i’ve come across 👌🏼

[@BarakAlmog]

Appreciate your effort so much! Thanks. I agree the font is a bit of a challenge,... still like it tho :) Thanks again!

[@Maverick2k]

Just wanted to give kudos for your videos. I'm a senior dev, finally dabbling in proper testing and I found this video really easy to understand. I was wondering though, what which point is it better to spy vs mock?

[@RRCaddick]

This is awesome! Was pulling my hair out yesterday dealing with jests mock hoisting and trying to change mock resolved for only a specific test, and I'm sure this will help. Why would we favour one over the other?

[@Mr_MicDaniel]

I really enjoyed the tutorial it was superb Can you do this for Vitest and Prisma ORM. Thank I will really appreciate it

[@malgorzatastefanowicz4077]

cant watch it because of the font :/

[@dev.channel]

Sorry for that. I will not use that font in future videos

[@aryakhaleqi1600]

Graet

[@sueluceromartinezherrera1825]

thanks! it was pretty clear, I just have a question, in this case the user file export the functions and you can import easily, but what happen if in my file The functions is not exported ? how can I access to that fuction in my test, hope I could be clear, greeting from mexico.

[@dev.channel]

If it’s not exported then it can’t be imported and not tested either

[@justinmiller3349]

@@dev.channel To be more precise, "private" or "internal" functions are not tested *directly* but as a developer you want to be aware of this and you can design your tests to ensure all of your internal logic is behaving as intended indirectly by ensuring that the imported function returns what is expected given several different inputs that the internal logic deals with. Using the --coverage flag with Jest can help uncover untested internal code.

[@iJuce]

Why would you upload a video with that font 🤦🏽‍♂️ it’s so unreadable

[@dev.channel]

Thanks for the feedback. I will remember to not use that :)

[@josuetavares49]

with this font it is difficult to read