I am running a build that install testthat, but always failed for Ubuntu & R version 3.4:
Error : object ‘col_align’ is not exported by 'namespace:crayon'
ERROR: lazy loading failed for package ‘cli’
* removing ‘/usr/local/R/R-3.4.0/lib/R/library/cli’
ERROR: dependency ‘cli’ is not available for package ‘testthat’
* removing ‘/usr/local/R/R-3.4.0/lib/R/library/testthat’