Travis CI not installing packages declared in DESCRIPTION file

Apologies in advance if this is a silly and too basic question but I couldn’t find any good reference about it and some of the hits for my searches are relatively old…

I’m developing an R package and I have the R packages dependencies stated in the DESCRIPTION file as imports.
My understanding was that Travis will automatically install these dependencies when installing my package but I have found that if I don’t do this in advance, the installation fails because the packages are not present.

IMHO having to explicitly install these packages in the .travis.yml configuration file defeats the purpose of the CI process… but it is quite possible that I’m missing something very basic…

I’d truly appreciate if you can advice or point to me some references about this.

FYI these are my DESCRIPTION and .travis.yml files:

Many thanks!

PS the Travis support team suggested me to reference @jeroen and @jimhester who may have some suggestions about this?

Travis should automatically install those, indeed. However you are overriding the install: section in your .travis file in which this happens. You should remove this section because it is redundant in the first place (travis also automatically installs R).

@jeroen many thanks, that worked and I guess it makes sense too.
Another quick question, are the checks for R windows working?
Anything special one should do to be able to test against a windows platform?

Also it appears to be failing for the MacOS R-devel version.

Error: (converted from warning) unable to access index for repository
223  cannot open URL ''

Indeed, the URL does not exist but instead one can see

CRAN does not provide binaries for r-devel on MacOS. It’s better to only test with r-devel on Linux. We do not support Windows in language:r on Travis.

I see, that was my guess.

Many thanks again!