There is no jest in dev-dependencies. I'm not sure if it is good idea to hide this. For example, I get this error message when installing the type definition of jest:

⇒  flow-typed install jest        
• Found [email protected] installed. Installing libdefs compatible with this version of Flow...
ERROR: Please specify an npm package name of the format '[email protected]'

But it is not trivial to find out now which version of jest I'm actually using.