testthat 2.2.0

New features

• New verify_output() is designed for testing output aimed at humans
  (most commonly print methods and error messages). It is a regression
  test that saves output in a way that makes it easy to review. It is
  automatically skipped on CRAN (#782, #834).

Minor improvements and bug fixes

• as.data.frame.testthat_results() now always returns a data frame with 13
  columns (@jozefhajnala, #887).

• auto_test_package() now correctly handles helper files
  (tests/testthat/helper-*.R), automatically reloading all code and
  rerunning all tests (@CorradoLanera, #376, #896).

• expect_match() now displays info even when match length is 0 (#867).

• expect_s3_class() gains new expect argument that allows you to check
  for an exact class match, not just inheritance (#885).

• fail() and succeed() gain info argument, which is passed along to
  expect().

• test_examples() gets some minor fixes: it now returns the results
  invisibly, doesn't assume that examples should contain tests, and
  documents that you shouldn't be using it routinely (#841).

• test_file() only calls Reporter$end_context() if a context was started,
  fixing an error in TeamcityReporter (@atheriel, #883).

• skip() now reports reason for skipping as: Reason: {skip condition}
  (@patr1ckm, #868).

• skip_if() and skip_if_not() now report Reason: {skip condition} is TRUE
  and Reason: {skip condition} is not TRUE respectively (@ patr1ckm, #868).

• skip_if_translated() now tests for translation of a specific message.
  This is more robust than the previous approach because translation
  happens message-by-message, not necessarily for the entire session (#879)
  (and in general, it's impossible to determine what language R is currently
  using).

• skip_on_covr() allows you to skip tests when covr is running.
  (@ianmcook, #895)

• expect_known_value() gains a new serialisation version argument,
  defaulting to 2. Prevents the .rds files created to hold reference objects
  from making a package appear to require R >= 3.5 (#888 @jennybc).