# testthat 2.1.1

* Fix test failures in strict latin1 locale

# testthat 2.1.0

## New expectations

* New `expect_visible()` and `expect_invisible()` make it easier to check if
  a function call returns its result visibly or invisibly (#719).

* New `expect_mapequal(x, y)` checks that `x` and `y` have the same names,
  and the same value associated with each name (i.e. they compare the values
  of the vector standardising the order of the names) (#863).

* New `expect_vector()` is a wrapper around `vctrs::vec_assert()` making it
  easy to test against the vctrs definitions of prototype and size (#846).
  (Currently requires development version of vctrs.)

## Improvements to existing expectations

* All expectations give clearer error messages if you forget the `object`
  or `expected` arguments (#743).

* `expect_equal()` now correctly compares infinite values (#789).

* In `expect_equal_to_reference()`, the default value for `update` is
  now `FALSE` (@BrodieG, #683).

* `expect_error()` now returns the error object as documentated (#724).
  It also now warns if you're using a classed expectation and you're
  not using the `class` argument. This is good practice as it decouples the 
  error object (which tends to be stable) from its rendering to the user 
  (which tends to be fragile) (#816).

* `expect_identical()` gains a `...` argument to pass additional arguments
  down to `identical()` (#714).

* `expect_lt()`, `expect_lte()`, `expect_gt()` `expect_gte()` now handle `Inf`
  and `NA` arguments appropriately (#732), and no longer require the inputs
  to be numeric.

* `expect_output()` gains a `width` argument, allowing you to control the 
  output width. This does not inherit from `getOption("width")`, ensuring 
  that tests return the same results regardless of environment (#805).

* `expect_setequal()` now works with more vector types (including lists),
  because it uses `%in%`, rather than `sort()`. It also warns if the inputs 
  are named, as this suggests that your mental model of how `expect_setequal()` 
  works is wrong (#750).

* `is_true()` and `is_false()` have been deprecated because they conflict
  with other functions in the tidyverse.

## Reporters

* Reporter documentation has been considerably improved (#657).

* `CheckReporter`, used by R CMD check, now includes a count of warnings.

* `JUnitReporter` no longer replaces `.` in class names (#753), and
  creates ouput that should be more compatible with Jenkins (#806, @comicfans).

* `ListReporter` now records number of passed tests and original results in 
  new columns (#675).

* `ProgressReporter`, the default reporter, now:

    * Automatically generates a context from the file name. We no longer
      recommend the use of `context()` and instead encourage you to delete it,
      allowing the context to be autogenerated from the file name.
      
      This also eliminates the error that occured if tests can before the
      first `context()` (#700, #705). 

    * Gains a `update_interval` parameter to control how often updates are 
      printed (default 0.1 s). This prevents large printing overhead
      for very fast tests. (#701, @jimhester)

    * Uses a 3 character wide column to display test successes, so up to
      999 successful tests can be displayed without changing the alignment 
      (#712).

* `reporter$end_reporter()` is now only called when testing completes 
  successfully. This ensures that you don't get unnecessary output when the 
  test fails partway through (#727).

## Skips

* `skip_if_offline()` skips tests if an internet connection is not available
  (#685).

* `skip_on_ci()` skips tests on continuous integration systems 
  (@mbjoseph, #825) by looking for a `CI` env var..

## Other new features

* New `testthat_examples()` and `testthat_example()` make it easy to access
  new test files bundled with the package. These are used in various examples
  to make it easier to understand how to use the package.

* New `local_mock()` which allows you to mock a function without having to
  add an additional layer of indentation as with `with_mock()` (#856).

## Other minor improvements and bug fixes

* `auto_test_package()` works better with recent devtools and also watches
  `src/` for changes (#809).

* `expect_s3_class()` now works with unquoting (@jalsalam, #771).

* `expectation` objects now contain the failure message, even when successful 
  (#836)

* `devtools::test()` no longer fails if run multiple times within the same R 
  session for a package containing Catch tests.
  ([devtools #1832](https://github.com/r-lib/devtools/issues/1832))

* New `testing_package()` retrieves the name of the package currently being 
  tested (#699).

* `run_testthat_tests` C entrypoint is registered more robustly.

* `skip()` now always produces a `message` of length 1, as expected elsewhere
  in testthat (#791).

* Warnings are passed through even when `options(warn = 2)` is set 
  (@yutannihilation, #721).

# testthat 2.0.1

* Fix failing tests with devtools 2.0.0

# testthat 2.0.0

## Breaking API changes

* "Can't mock functions in base packages": You can no longer use `with_mock()` 
  to mock functions in base packages, because this no longer works in 
  R-devel due to changes with the byte code compiler. I recommend using
  [mockery](https://github.com/n-s-f/mockery) or 
  [mockr](https://github.com/krlmlr/mockr) instead.

* The order of arguments to `expect_equivalent()` and `expect_error()` has
  changed slightly as both now pass `...` on another function. This reveals
  itself with a number of different errors, like:
  
    * 'what' must be a character vector
    * 'check.attributes' must be logical
    * 'tolerance' should be numeric
    * argument is not interpretable as logical
    * threw an error with unexpected class
    * argument "quo" is missing, with no default
    * argument is missing, with no default
    
    If you see one of these errors, check the number, order, and names of 
    arguments to the expectation.

* "Failure: (unknown)". The last release mistakenly failed to test 
  bare expectations not wrapped inside `test_that()`. If you see "(unknown)"
  in a failure message, this is a failing expectation that you previously
  weren't seeing. As well as fixing the failure, please also wrap inside
  a `test_that()` with an informative name.
  
* "Error: the argument has already been evaluated": the way in which 
  expectations now need create labels has changed, which caused a couple 
  of failures with unusual usage when combined with `Reduce`, `lapply()`, 
  and `Map()`. Avoid these functions in favour of for loops. I also recommend
  reading the section below on quasiquotation support in order to create more 
  informative failure messages.
  
## Expectations

### New and improved expectations

* `expect_condition()` works like `expect_error()` but captures any
  condition, not just error conditions (#621).

* `expect_error()` gains a `class` argument that allows you to make an 
  assertion about the class of the error object (#530).

* `expect_reference()` checks if two names point to the same object (#622).

* `expect_setequal()` compares two sets (stored in vectors), ignoring
  duplicates and differences in order (#528).

### New and improved skips

* `skip_if()` makes it easy to skip a test when a condition is true (#571).
  For example, use `skip_if(getRversion() <= 3.1)` to skip a test in older
  R versions.

* `skip_if_translated()` skips tests if you're running in an locale
  where translations are likely to occur (#565). Use this to avoid
  spurious failures when checking the text of error messages in non-English
  locales.
  
* `skip_if_not_installed()` gains new `minimum_version` argument (#487, #499).

### Known good values

We have identified a useful family of expectations that compares the results of an expression to a known good value stored in a file. They are designed to be use in conjunction with git so that you can see what precisely has changed, and revert it if needed.

* `expect_known_output()` replaces `expect_output_file()`, which has
  been soft-deprecated. It now defaults to `update = TRUE` and warn, rather
  than failing on the first run. It gains a `print` argument to automatically 
  print the input (#627). It also sets the width option to 80 to ensure 
  consistent output across environments (#514)

* `expect_known_value()` replaces `expect_equal_to_reference()`, which
  has been soft-deprecated. It gains an update argument defaulting to `TRUE`.
  This changes behaviour from the previous version, and soft-deprecated
  `expect_equal_to_reference()` gets `update = FALSE`. 

* `expect_known_failure()` stored and compares the failure message from
  an expectation. It's a useful regression test when developing informative
  failure messges for your own expectations.

### Quasiquotation support

All expectations can now use unquoting (#626). This makes it much easier to generate informative failure messages when running tests in a for loop.

For example take this test:

```R
f <- function(i) if (i > 3) i * 9 else i * 10

for (i in 1:5) {
  expect_equal(f(i), i * 10)
}
```

When it fails, you'll see the message ``Error: `f(i)` not equal to `i * 10` ``.
That's hard to diagnose because you don't know which iteration caused the problem!

```R
for (i in 1:5) {
  expect_equal(f(!!i), !!(i * 10))
}
```

If you unquote the values using `!!`, you get the failure message `` `f(4L)` not equal to 40.``. This is much easier to diagnose!  See `?quasi_label()` for more details.

(Note that this is not tidy evaluation per se, but is closely related. At this time you can not unquote quosures.)

## New features

### Setup and teardown

* New `setup()` and `teardown()` functions allow you to run at the start and
  end of each test file. This is useful if you want to pair cleanup code
  with the code that messes up state (#536). 

* Two new prefixes are recognised in the `test/` directory. Files starting
  with `setup` are run before tests (but unlike `helpers` are not run in
  `devtools::load_all()`). Files starting with `teardown` are run after all
  tests are completed (#589).

### Other new features

* All files are now read and written as UTF-8 (#510, #605).

* `is_testing()` allows you to tell if your code is being run inside a 
  testing environment (#631). Rather than taking a run-time dependency on testthat
  you may want to inline the function into your own package:
  
    ```R
    is_testing <- function() {
      identical(Sys.getenv("TESTTHAT"), "true")
    }
    ```
    
    It's frequently useful to combine with `interactive()`.

### New default reporter

A new default reporter, `ReporterProgress`, produces more aesthetically pleasing output and makes the most important information available upfront (#529). You can return to the previous default by setting `options(testthat.default_reporter = "summary")`.

### Reporters

* Output colours have been tweaked to be consistent with clang:
  warnings are now in magenta, and skips in blue.

* New `default_reporter()` and `check_reporter()` which returns the default 
  reporters for interactive and check environments (#504).

* New `DebugReporter` that calls a better version of `recover()` in case of 
  failures, errors, or warnings (#360, #470).

* New `JunitReporter` generates reports in JUnit compatible format.  
  (#481, @lbartnik; #640, @nealrichardson; #575)

* New `LocationReporter` which just prints the location of every expectation.
  This is useful for locating segfaults and C/C++ breakpoints (#551).

* `SummaryReporter` recieved a number of smaller tweaks

  * Aborts testing as soon the limit given by the option 
    `testthat.summary.max_reports` (default 10) is reached (#520).
    
  * New option `testthat.summary.omit_dots = TRUE` hides the progress dots
    speeding up tests by a small amount (#502).

  * Bring back random praise and encouragement which I accidentally dropped 
    (#478).

* New option `testthat.default_check_reporter`, defaults to `"check"`. 
  Continuous Integration system can set this option before evaluating
  package test sources in order to direct test result details to known
  location.

* All reporters now accept a `file` argument on initialization. If provided, 
  reporters will write the test results to that path. This output destination 
  can also be controlled with the option `testthat.output_file` 
  (#635, @nealrichardson).

## Deprecated functions

* `is_null()` and `matches()` have been deprecated because they conflict
  with other functions in the tidyverse (#523).

## Minor improvements and bug fixes

* Updated Catch to 1.9.6. `testthat` now understands and makes use of the package
  routine registration mechanism required by CRAN with R >= 3.4.0. 
  (@kevinushey)

* Better reporting for deeply nested failures, limiting the stack trace to the 
  first and last 10 entries (#474).

* Bare expectations notify the reporter once again. This is achieved by running 
  all tests inside `test_code()` by default (#427, #498). This behaviour can be 
  overridden by setting `wrap = FALSE` in `test_dir()` and friends (#586).

* `auto_test()` and `auto_test_package()` provide `hash` parameter to enable 
  switching to faster, time-stamp-based modification detection
  (#598, @katrinleinweber). `auto_test_package()` works correctly on windows 
  (#465). 

* `capture_output_lines()` is now exported (#504).

* `compare.character()` works correctly for vectors of length > 5 (#513, @brodieG)

* `compare.default()` gains a `max_diffs` argument and defaults to printing
  out only the first 9 differences (#538).

* `compare.numeric()` respects `check.attributes()` so `expect_equivalent()`
  correctly ignores attributes of numeric vectors (#485).

* Output expectations (`expect_output()`, `expect_message()`, 
  `expect_warning()`, and `expect_silent()`) all invisibly return the first
  argument to be consistent with the other expectations (#615).

* `expect_length()` works with any object that has a `length` method, not
  just vectors (#564, @nealrichardson)

* `expect_match()` now accepts explicit `perl` and `fixed` arguments, and adapts
  the failure message to the value of `fixed`. This also affects other expectations
  that forward to `expect_match()`, like `expect_output()`, `expect_message()`,
  `expect_warning()`, and `expect_error()`.

* `expect_match()` escapes special regular expression characters when printing 
  (#522, @jimhester).

* `expect_message()`, `expect_warning()` and `expect_error()` produce clearer
  failure messages.

* `find_test_scripts()` only looks for `\.[rR]` in the extension 
  (#492, @brodieG)
  
* `test_dir()`, `test_package()`, `test_check()` unset the `R_TESTS` env var 
  (#603)

* `test_examples()` now works with installed packages as well as source
  packages (@jimhester, #532).

* `test_dir()`, `test_package()`, and `test_check()` gain `stop_on_failure` 
  and `stop_on_waring` arguments that control whether or not an error 
  is signalled if any tests fail or generate warnings (#609, #619).

* `test_file()` now triggers a `gc()` after tests are run. This helps
  to ensure that finalisers are run earlier (#535).

* `test_path()` now generates correct path when called from within 
  `tools::testInstalledPackage()` (#542).

* `test_path()` no longer assumes that the path exists (#448).

* `test_that()` calls without any expectations generate a default `skip()` 
  (#413).

* `test_dir()` gains `load_helpers` argument  (#505).

* `show_failures()` simply prints a failure if it occurs. This makes it easier
  to show failures in examples.

* `with_mock()` disallows mocking of functions in base packages, because this 
  doesn't work with the current development version of R (#553).

# testthat 1.0.2

* Ensure `std::logic_error()` constructed with `std::string()`
  argument, to avoid build errors on Solaris.

# testthat 1.0.1

* New `expect_output_file()` to compare output of a function
  with a text file, and optionally update it (#443, @krlmlr).

* Properly scoped use + compilation of C++ unit testing code using
  Catch to `gcc` and `clang` only, as Catch includes code that does
  not strictly conform to the C++98 standard. (@kevinushey)

* Fixed an out-of-bounds memory access when routing Catch output
  through `Rprintf()`. (@kevinushey)
  
* Ensure that unit tests run on R-oldrel (remove use of `dir.exists()`).
  (@kevinushey)
  
* Improved overriding of calls to `exit()` within Catch, to ensure
  compatibility with GCC 6.0. (@krlmlr)

* Hardened formatting of difference messages, previously the presence of `%` 
  characters could affect the output (#446, @krlmlr).
  
* Fixed errors in `expect_equal()` when comparing numeric vectors with and 
  without attributes (#453, @krlmlr).

* `auto_test()` and `auto_test_package()` show only the results of the 
  current test run and not of previously failed runs (#456, @krlmlr).

# testthat 1.0.0

## Breaking changes

The `expectation()` function now expects an expectation type (one of "success", "failure", "error", "skip", "warning") as first argument. If you're creating your own expectations, you'll need to use `expect()` instead (#437).

## New expectations

The expectation system got a thorough overhaul (#217). This primarily makes it easier to add new expectations in the future, but also included a thorough review of the documentation, ensuring that related expectations are documented together, and have evocative names.

One useful change is that most expectations invisibly return the input `object`. This makes it possible to chain together expectations with magrittr:
    
```R
factor("a") %>% 
  expect_type("integer") %>% 
  expect_s3_class("factor") %>% 
  expect_length(1)
```

(And to make this style even easier, testthat now re-exports the pipe, #412).

The exception to this rule are the expectations that evaluate (i.e.
for messages, warnings, errors, output etc), which invisibly return `NULL`. These functions are now more consistent: using `NA` will cause a failure if there is a errors/warnings/mesages/output (i.e. they're not missing), and will `NULL` fail if there aren't any errors/warnings/mesages/output. This previously didn't work for `expect_output()` (#323), and the error messages were confusing with `expect_error(..., NA)` (#342, @nealrichardson + @krlmlr, #317).

Another change is that `expect_output()` now requires you to explicitly print the output if you want to test a print method: `expect_output("a", "a")` will fail, `expect_output(print("a"), "a")` will succeed.

There are six new expectations:

* `expect_type()` checks the _type_ of the object (#316), 
  `expect_s3_class()` tests that an object is S3 with given class,
  `expect_s4_class()` tests that an object is S4 with given class (#373).
  I recommend using these more specific expectations instead of the
  more general `expect_is()`.

* `expect_length()` checks that an object has expected length.

* `expect_success()` and `expect_failure()` are new expectations designed
  specifically for testing other expectations (#368).

A number of older features have been deprecated:

* `expect_more_than()` and `expect_less_than()` have been deprecated. Please
  use `expect_gt()` and `expect_lt()` instead.

* `takes_less_than()` has been deprecated.

* `not()` has been deprecated. Please use the explicit individual forms
  `expect_error(..., NA)` , `expect_warning(.., NA)` and so on.


## Expectations are conditions

Now all expectations are also conditions, and R's condition system is used to signal failures and successes (#360, @krlmlr). All known conditions (currently, "error", "warning", "message", "failure", and "success") are converted to expectations using the new `as.expectation()`. This allows third-party test packages (such as `assertthat`, `testit`, `ensurer`, `checkmate`, `assertive`) to seamlessly establish `testthat` compatibility by issuing custom error conditions (e.g., `structure(list(message = "Error message"), class = c("customError", "error", "condition"))`) and then implementing `as.expectation.customError()`. The `assertthat` package contains an example.


## Reporters

The reporters system class has been considerably refactored to make existing reporters simpler and to make it easier to write new reporters. There are two main changes:

* Reporters classes are now R6 classes instead of Reference Classes.

* Each callbacks receive the full context: 

    * `add_results()` is passed context and test as well as the expectation.
    * `test_start()` and `test_end()` both get the context and test.
    * `context_start()` and `context_end()` get the context. 

* Warnings are now captured and reported in most reporters.

* The reporter output goes to the original standard output and is not affected by `sink()` and `expect_output()` (#420, @krlmlr).

* The default summary reporter lists all warnings (#310), and all skipped
  tests (@krlmlr, #343). New option `testthat.summary.max_reports` limits 
  the number of reports printed by the summary reporter. The default is 15 
  (@krlmlr, #354).

* `MinimalReporter` correct labels errors with E and failures with F (#311).

* New `FailReporter` to stop in case of failures or errors after all tests
  (#308, @krlmlr).

## Other

* New functions `capture_output()`, `capture_message()`, and 
  `capture_warnings()` selectively capture function output. These are 
  used in `expect_output()`, `expect_message()` and `expect_warning()`
  to allow other types out output to percolate up (#410).

* `try_again()` allows you to retry code multiple times until it succeeds
  (#240).

* `test_file()`, `test_check()`, and `test_package()` now attach testthat so
  all testing functions are available.

* `source_test_helpers()` gets a useful default path: the testthat tests 
  directory. It defaults to the `test_env()` to be consistent with the
  other source functions (#415).

* `test_file()` now loads helpers in the test directory before running
  the tests (#350).

* `test_path()` makes it possible to create paths to files in `tests/testthat`
  that work interactively and when called from tests (#345).

* Add `skip_if_not()` helper.

* Add `skip_on_bioc()` helper (@thomasp85).

* `make_expectation()` uses `expect_equal()`.

* `setup_test_dir()` has been removed. If you used it previously, instead use
  `source_test_helpers()` and `find_test_scripts()`.

* `source_file()` exports the function testthat uses to load files from disk.

* `test_that()` returns a `logical` that indicates if all tests were successful 
  (#360, @krlmlr).

* `find_reporter()` (and also all high-level testing functions) support a vector 
  of reporters. For more than one reporter, a `MultiReporter` is created 
  (#307, @krlmlr).

* `with_reporter()` is used internally and gains new argument 
  `start_end_reporter = TRUE` (@krlmlr, 355).

* `set_reporter()` returns old reporter invisibly (#358, @krlmlr).

* Comparing integers to non-numbers doesn't raise errors anymore, and falls 
  back to string comparison if objects have different lengths. Complex numbers 
  are compared using the same routine (#309, @krlmlr).

* `compare.numeric()` and `compare.character()` received another overhaul. This 
  should improve behaviour of edge cases, and provides a strong foundation for 
  further work. Added `compare.POSIXt()` for better reporting of datetime
  differences.

* `expect_identical()` and `is_identical_to()` now use `compare()` for more
  detailed output of differences (#319, @krlmlr).

* Added [Catch](https://github.com/philsquared/Catch) v1.2.1 for unit testing of C++ code.
  See `?use_catch()` for more details. (@kevinushey)

# testthat 0.11.0

* Handle skipped tests in the TAP reporter (#262).

* New `expect_silent()` ensures that code produces no output, messages,
  or warnings (#261).

* New `expect_lt()`, `expect_lte()`, `expect_gt()` and `expect_gte()` for
  comparison with or without equality (#305, @krlmlr).

* `expect_output()`, `expect_message()`, `expect_warning()`, and
  `expect_error()` now accept `NA` as the second argument to indicate that
  output, messages, warnings, and errors should be absent (#219).

* Praise gets more diverse thanks to the praise package, and you'll now
  get random encouragment if your tests don't pass.

* testthat no longer muffles warning messages. If you don't want to see them 
  in your output, you need to explicitly quiet them, or use an expectation that 
  captures them (e.g. `expect_warning()`). (#254)

* Use tests in `inst/tests` is formally deprecated. Please move them into
  `tests/testthat` instead (#231).

* `expect_match()` now encodes the match, as well as the output, in the 
  expectation message (#232).

* `expect_is()` gives better failure message when testing multiple inheritance,
  e.g. `expect_is(1:10, c("glm", "lm"))` (#293).

* Corrected argument order in `compare.numeric()` (#294).

* `comparison()` constructure now checks its arguments are the correct type and
  length. This bugs a bug where tests failed with an error like "values must be 
  length 1, but FUN(X[[1]]) result is length 2" (#279).

* Added `skip_on_os()`, to skip tests on specified operating systems
  (@kevinushey).

* Skip test that depends on `devtools` if it is not installed (#247, @krlmlr)

* Added `skip_on_appveyor()` to skip tests on Appveyor (@lmullen).

* `compare()` shows detailed output of differences for character vectors of
  different length (#274, @krlmlr).

* Detailed output from `expect_equal()` doesn't confuse expected and actual
  values anymore (#274, @krlmlr).

# testthat 0.10.0

* Failure locations are now formated as R error locations.

* Add an 'invert' argument to `find_tests_scripts()`.  This allows one to
  select only tests which do _not_ match a pattern. (#239, @jimhester).

* Deprecated `library_if_available()` has been removed.

* test (`test_dir()`, `test_file()`, `test_package()`, `test_check()`) functions 
  now return a `testthat_results` object that contains all results, and can be 
  printed or converted to data frame.

* `test_dir()`, `test_package()`, and `test_check()` have an added `...`
  argument that allows filtering of test files using, e.g., Perl-style regular
  expressions,or `fixed` character filtering. Arguments in `...` are passed to
  `grepl()` (@leeper).

* `test_check()` uses a new reporter specifically designed for `R CMD check`.
  It displays a summary at the end of the tests, designed to be <13 lines long
  so test failures in `R CMD check` display something more useful. This will
  hopefully stop BDR from calling testthat a "test obfuscation suite" (#201).

* `compare()` is now documented and exported. Added a numeric method so when
  long numeric vectors don't match you'll see some examples of where the
  problem is (#177). The line spacing in `compare.character()` was
  tweaked.

* `skip_if_not_installed()` skips tests if a package isn't installed (#192).

* `expect_that(a, equals(b))` style of testing has been soft-deprecated.
  It will keep working, but it's no longer demonstrated any where, and new
  expectations will only be available in `expect_equal(a, b)` style. (#172)

* Once again, testthat suppresses messages and warnings in tests (#189)

* New `test_examples()` lets you run package examples as tests. Each example
  counts as one expectation and it succeeds if the code runs without errors
  (#204).

* New `succeed()` expectation always succeeds.

* `skip_on_travis()` allows you to skip tests when run on Travis CI.
  (Thanks to @mllg)

* `colourise()` was removed. (Colour is still supported, via the `crayon` 
  package.)

* Mocks can now access values local to the call of `with_mock` (#193, @krlmlr).

* All equality expectations are now documented together (#173); all
  matching expectations are also documented together.

# testthat 0.9.1

* Bump R version dependency

# testthat 0.9

## New features

* BDD: testhat now comes with an initial behaviour driven development (BDD)
  interface. The language is similiar to RSpec for Ruby or Mocha for JavaScript.
  BDD tests read like sentences, so they should make it easier to understand
  the specification of a function. See `?describe()` for further information
  and examples.

* It's now possible to `skip()` a test with an informative message - this is
  useful when tests are only available under certain conditions, as when
  not on CRAN, or when an internet connection is available (#141).

* `skip_on_cran()` allows you to skip tests when run on CRAN. To take advantage
  of this code, you'll need either to use devtools, or run
  `Sys.setenv(NOT_CRAN = "true"))`

* Simple mocking: `with_mock()` makes it easy to temporarily replace
  functions defined in packages. This is useful for testing code that relies
  on functions that are slow, have unintended side effects or access resources
  that may not be available when testing (#159, @krlmlr).

* A new expectation, `expect_equal_to_reference()` has been added. It
  tests for equality to a reference value stored in a file (#148, @jonclayden).

## Minor improvements and bug fixes

* `auto_test_package()` works once more, and now uses `devtools::load_all()`
  for higher fidelity loading (#138, #151).

* Bug in `compare.character()` fixed, as reported by Georgi Boshnakov.

* `colourise()` now uses option `testthat.use_colours` (default: `TRUE`). If it
  is `FALSE`, output is not colourised (#153, @mbojan).

* `is_identical_to()` only calls `all.equal()` to generate an informative
  error message if the two objects are not identical (#165).

* `safe_digest()` uses a better strategy, and returns NA for directories
  (#138, #146).

* Random praise is renabled by default (again!) (#164).

* Teamcity reporter now correctly escapes output messages (#150, @windelinckx).
  It also uses nested suites to include test names.

## Deprecated functions

* `library_if_available()` has been deprecated.

# testthat 0.8.1

* Better default environment for `test_check()` and `test_package()` which
  allows S4 class creation in tests

* `compare.character()` no longer fails when one value is missing.

# testthat 0.8

testthat 0.8 comes with a new recommended structure for storing your tests. To
better meet CRAN recommended practices, testthat now recommend that you to put
your tests in `tests/testthat`, instead of `inst/tests` (this makes it
possible for users to choose whether or not to install tests). With this
new structure, you'll need to use `test_check()` instead of `test_packages()`
in the test file (usually `tests/testthat.R`) that runs all testthat unit
tests.

The other big improvement to usability comes from @kforner, who contributed
code to allow the default results (i.e. those produced by `SummaryReporter`)
to include source references so you can see exactly where failures occured.

## New reporters

* `MultiReporter`, which combines several reporters into one.
  (Thanks to @kforner)

* `ListReporter`, which captures all test results with their file,
  context, test and elapsed time. `test_dir`, `test_file`, `test_package` and
  `test_check` now use the `ListReporter` to invisibly  return a summary of
  the tests as a data frame. (Thanks to @kforner)

* `TeamCityReporter` to produce output compatible with the TeamCity
  continuous integration environment. (Thanks to @windelinckx)

* `SilentReporter` so that  `testthat` can test calls to `test_that`.
  (Thanks to @craigcitro, #83)

## New expectations

* `expect_null()` and `is_null` to check if an object is NULL (#78)

* `expect_named()` and `has_names()` to check the names of a vector (#79)

* `expect_more_than()`, `is_more_than()`, `expect_less_than()`,
  `is_less_than()` to check values above or below a threshold.
  (#77, thanks to @jknowles)

## Minor improvements and bug fixes

* `expect_that()` (and thus all `expect_*` functions) now invisibly return
  the expectation result, and stops if info or label arguments have
  length > 1 (thanks to @kforner)

* fixed two bugs with source_dir(): it did not look for the source scripts
  at the right place, and it did not use its `chdir` argument.

* When using `expect_equal()` to compare strings, the default output for
  failure provides a lot more information, which should hopefully help make
  finding string mismatches easier.

* `SummaryReporter` has a `max_reports` option to limit the number of detailed
  failure reports to show. (Thanks to @crowding)

* Tracebacks will now also contain information about where the functions came
  from (where that information is available).

* `matches` and `expect_match` now pass additional arguments on to `grepl` so
  that you can use `fixed = TRUE`, `perl = TRUE` or `ignore.case = TRUE` to
  control details of the match. `expect_match` now correctly fails to match
  NULL. (#100)

* `expect_output`, `expect_message`, `expect_warning` and `expect_error`
  also pass ... on to `grepl`, so that you can use  `fixed = TRUE`,
  `perl = TRUE` or `ignore.case = TRUE`

* Removed `stringr` and `evaluate` dependencies.

* The `not()` function makes it possible to negate tests. For example,
  `expect_that(f(), not(throws_error()))` asserts that `f()` does not
  throw an error.

* Make `dir_state` less race-y. (Thanks to @craigcitro, #80)

* `auto_test` now pays attention to its 'reporter' argument (Thanks to @crowding, #81)

* `get_reporter()`, `set_reporter()` and `with_reporter()` are now
  exported (#102)


# testthat 0.7.1

* Ignore attributes in `is_true` and `is_false` (#49)

* `make_expectation` works for more types of input (#52)

* Now works better with evaluate 0.4.3.

* new `fail()` function always forces a failure in a test. Suggested by
  Richie Cotton (#47)

* Added `TapReporter` to produce output compatible with the "test anything
  protocol". Contributed by Dan Keshet.

* Fixed where `auto_test` would identify the wrong files as having changed.
  (Thanks to Peter Meilstrup)

# testthat 0.7

* `SummaryReporter`: still return informative messages even if no tests
  defined (just bare expectations). (Fixes #31)

* Improvements to reference classes (Thanks to John Chambers)

* Bug fixes for when nothing was generated in `gives_warning` /
  `shows_message`. (Thanks to Bernd Bischl)

* New `make_expectation` function to programmatically generate an equality
  expectation. (Fixes #24)

* `SummaryReporter`: You don't get praise until you have some tests.

* Depend on `methods` rather than requiring it so that testthat works when run
  from `Rscript`

* `auto_test` now normalises paths to enable better identification of file
  changes, and fixes bug in instantiating new reporter object.

# testthat 0.6

* All `mutatr` classes have been replaced with ReferenceClasses.

* Better documentation for short-hand expectations.

* `test_dir` and `test_package` gain new `filter` argument which allows you to
   restrict which tests are run.

# testthat 0.5

* bare expectations now correctly throw errors again

# testthat 0.4

* autotest correctly loads code and executes tests in same environment

* contexts are never closed before they are opened, and always closed at the
  end of file

* fixed small bug in `test_dir` where each test was not given its own
  environment

* all `expect_*` short cut functions gain a label argument, thanks to Steve
  Lianoglou

# testthat 0.3

* all expectations now have a shortcut form, so instead of
     expect_that(a, is_identical_to(b))
  you can do
     expect_identical(a, b)

* new shows_message and gives_warning expectations to test warnings and
  messages

* expect_that, equals, is_identical_to and is_equivalent to now have
  additional label argument which allows you to control the appearance of the
  text used for the expected object (for expect_that) and actual object (for
  all other functions) in failure messages. This is useful when you have loops
  that run tests as otherwise all the variable names are identical, and it's
  difficult to tell which iteration caused the failure.

* executing bare tests gives nicer output

* all expectations now give more information on failure to make it easier to
  track down the problem.

* test_file and test_dir now run in code in separate environment to avoid
  pollution of global environment. They also temporary change the working
  directory so tests can use relative paths.

* test_package makes it easier to run all tests in an installed package. Code
  run in this manner has access to non-exported functions and objects. If any
  errors or failures occur, test_package will throw an error, making it
  suitable for use with R CMD check.

# testthat 0.2

* colourise also works in screen terminal

* equals expectation provides more information about failure

* expect_that has extra info argument to allow you to pass in any extra
  information you'd like included in the message - this is very helpful if
  you're using a loop to run tests

* is_equivalent_to: new expectation that tests for equality ignoring
  attributes

* library_if_available now works! (thanks to report and fix from Felix
  Andrews)

* specify larger width and join pieces back together whenever deparse used
  (thanks to report and fix from Felix Andrews)

* test_dir now looks for any files starting with test (not test- as before)
