Is there a location at which tentative plans/timelines for gradethis are revealed/discussed?
I (and others, I suspect) are very interested in incorporating gradethis into our course workflows for September. But that, of course, depends on where gradethis will be at. I get very nervous when I see a package removed from CRAN . . .
It's not gradethis, but there is a new R/R Markdown/R jupyter Notebook autograding package called ottr, built over the testthat package. Otter Grader is a Python autograder used in some of UC Berkeley's large Data Science courses. The developers have just added limited support for R (and .Rmd, R .ipynb). For now, the autograder must be deployed through Gradescope, but if there is interest, I think they would add local autograding capability. Find more info on the R capabilities here, and info on the larger project (including Slack channel) here.