Warning in .doLoadActions(where, attach)

[maurolepore]

With R 3.2 on Travis CI I got this warning:

Warning message:
In .doLoadActions(where, attach) :
  trying to execute load actions without 'methods' package

Following this post I added library(methods) to .travis.yml as follows:

matrix:
  include:
  # ... more stuff
  - r: 3.3
  - r: 3.2
    script: Rscript -e 'library(methods)'

This fixed the problem