Specs are quantitative aspects of the option such as the price
Pros
Pro
Natively supports mocking
Jest has out-of-the box support for mocking functions. This is extremely helpful when you want to test asynchronous functions in a completely synchronous way.
It's great for testing UI. It is also convenient for asserting complex data objects, as it doesn't require developers to manually compose the expected value.
Like almost everything else release by Facebook (unfortunately), Jest has terrible documentation. It has a very basic example where everything is explained poorly. It doesn't explain most concepts or how everything fits together.