Create a raven-testdata repo

[Zeitsperre]

@tlvu

@huard would like for us to create a raven-testdata repository to support Raven (and PyRaven, I imagine). He mentioned that you had already started some work on this. My questions to you are :

• Would you want something that very closely resembled xclim-testdata ?
  • Would this repo include a script for generating an MD5 sum for files ?
• What types of files will likely be in this repo ?
  • Would they be very large ? Do we need git-lfs ?
• Any other pertinent needs ?

[tlvu]

@Zeitsperre @huard I though the conclusion was to leave the raven test data where they currently are (in the Raven repo), as in this comment Ouranosinc/xclim-testdata#1 (comment), reasoning Ouranosinc/xclim-testdata#1 (comment).

I did not have time to finish #185 and I believe what's left to do are:

• Create a function raven.tutorial.get_file that knows how to handle different file types. In the case of netCDF either returns an http or dap link from thredds, and for other files return the rawgithub link (see Sync testdata folder to THREDDS testdata/raven #185 (comment))

• Given this raven.tutorial.get_file function is part of the same Raven repo as the testdata, it should detect that the testdata are local (the case of a dev checkout and running CI) and return the local file instead of always fetching it over the internet. Further reasoning Sync testdata folder to THREDDS testdata/raven #185 (comment).

[Zeitsperre]

https://github.com/Ouranosinc/raven-testdata