defer() can set deferred events on .GlobalEnv to facilitate the interactive development of code inside a function or test. Helpers deferred_run() (and deferred_clear()) provide a way to explicity run and clear (or just clear) deferred events (#76, @jennybc).
with_connection() now works when existing objects or connections exist with the same names (#120)
with_makevars() now uses tools::makevars_user() to determine the default user makevars file (#77, @siddharthab).
with_options() no longer uses do.call(), so optiosn are not evaluated on exit (#73, @mtmorgan).
with_package() no longer has the help argument (#94, @wendtke).
with_package() now does not try to detach the package if it is already attached before calling with_package() (#107)
with_preserve_seed() now restores .Random.seed if it is not set originally (#124).
Add with_rng_version() and local_rng_version() functions to change the version of the RNG (#90, @gaborcsardi).
with_svg() documentation now is consistent across R versions (#129)
Add with_timezone() and local_timezone() functions to change the time zone (#92, @gaborcsardi).
with_tempfile() and local_tempfile() now delete recursively directories on exit (#84, @meta00).
set_makevars() is now exported (#68, @gaborcsardi).
with_temp_libpaths() gains an action argument, to specify how the temporary library path will be added (#66, @krlmlr).
Fixes test failures with testthat 2.0.0
with_file() function to automatically remove files.
with_connection() function to automatically close R file connections.
with_db_connection() function to automatically disconnect from DBI database connections.
with_gctorture2 command to run code with gctorture2, useful for testing (#47).
with_package(), with_namespace() and with_environment() (and equivalent locals) functions added, to run code with a modified object search path (#38, #48).
Add with_tempfile() and local_tempfile() functions to create temporary files which are cleanup up afterwards. (#32)
Remove the code argument from local_ functions (#50).
Each with_ function now has a local_ variant, which reset at the end of their local scope, generally at the end of the function body.
New functions with_seed() and with_preserve_seed() for running code with a given random seed (#45, @krlmlr).
with_makevars() gains an assignment argument to allow specifying additional assignment types.with_output_sink() and with_message_sink() (#24).