Documentation example for __mocks__ implementation

[mdpratt]

This package makes mocking on a spec by spec significantly easier. However sometimes I would like to mock a client with a default behavior across many packages; for example, mocking STS' GetCallerIdentityCommand. Some documentation on how to put this into a toplevel __mocks__ would be appreciated.

If I figure it out, I'll open a pull request, but automocks is something that trips me up almost every time getting it just right.

[m-radzikowski]

I'm unsure if using (Jest) __mocks__ dir is a solution here because it replaces local modules with mocks. What you can try is maybe setting mock behavior in setupFilesAfterEnv script? If you make it work, please share.

[crs1138]

@mdpratt if you do work it out, could you mention it here please?