tests/testthat/_snaps/snapshot.md

In testthat: Unit Testing for R

can snapshot output

y

y

y

y

can snapshot everything

Code
  f()
Output
  [1] "1"
Message
  2
Condition
  Warning in `f()`:
  3
  Error in `f()`:
  ! 4

empty lines are preserved

Code
  f()
Output
  1

Message
  2

Condition
  Warning in `f()`:
  3
  Error in `f()`:
  ! 4

line-endings fixed before comparison

Code
  cat(x)
Output
  a
  b

multiple outputs of same type are collapsed

Code
  x <- 1
  y <- 1
  {
    message("a")
    message("b")
  }
Message
  a
  b
Code
  {
    warning("a")
    warning("b")
  }
Condition
  Warning:
  a
  Warning:
  b

can scrub output/messages/warnings/errors

Code
  secret()
Output
  [1] "<redacted>"
Message
  <redacted>
Condition
  Warning in `<redacted>()`:
  <redacted>
  Error in `<redacted>()`:
  ! <redacted>

Code
  print("secret")
Output
  [1] "****"

can capture error/warning messages

This is an error

This is a warning

snapshot captures deprecations

Code
  foo()
Condition
  Warning:
  `foo()` was deprecated in testthat 1.0.0.

`foo()` was deprecated in testthat 1.0.0.

`foo()` was deprecated in testthat 1.0.0.

can check error/warning classes

Code
  expect_snapshot_error(1)
Condition
  Error:
  ! 1 did not generate error

Code
  expect_snapshot_error(1, class = "myerror")
Condition
  Error:
  ! 1 did not generate error with class 'myerror'

Code
  expect_snapshot_warning(1)
Condition
  Error:
  ! 1 did not generate warning

Code
  expect_snapshot_warning(1, class = "mywarning")
Condition
  Error:
  ! 1 did not generate warning with class 'mywarning'

snapshot handles multi-line input

Code
  1 + 2
Output
  [1] 3
Code
  3 + 4
Output
  [1] 7
Code
  # this is a comment

snapshot captures output if visible

Code
  f_visible()
Output
  [1] "x"

Code
  f_invisible()

captures custom classes

Code
  f()
Message
  Hello
Condition
  Warning:
  Goodbye
  Error in `f()`:
  ! Eeek!

even with multiple lines

a
b
c

a
b
c

expect_snapshot() does not inject

Code
  x <- quote(!!foo)
  expect_equal(x, call("!", call("!", quote(foo))))

full condition message is printed with rlang

Code
  foo <- error_cnd("foo", message = "Title parent.")
  abort("Title.", parent = foo)
Condition
  Error:
  ! Title.
  Caused by error:
  ! Title parent.

can print with and without condition classes

Code
  f()
Message <simpleMessage>
  foo
Condition <simpleWarning>
  Warning in `f()`:
  bar
Condition <simpleError>
  Error in `f()`:
  ! baz

Code
  f()
Message
  foo
Condition
  Warning in `f()`:
  bar
  Error in `f()`:
  ! baz

errors and warnings are folded

Code
  f()
Condition
  Warning in `f()`:
  foo
  Error in `f()`:
  ! bar

hint is informative

Code
  cat(snapshot_accept_hint("_default", "bar.R", reset_output = FALSE))
Output
  * Run ]8;;ide:run:testthat::snapshot_accept('bar.R')testthat::snapshot_accept('bar.R')]8;; to accept the change.
  * Run ]8;;ide:run:testthat::snapshot_review('bar.R')testthat::snapshot_review('bar.R')]8;; to interactively review the change.
Code
  cat(snapshot_accept_hint("foo", "bar.R", reset_output = FALSE))
Output
  * Run ]8;;ide:run:testthat::snapshot_accept('foo/bar.R')testthat::snapshot_accept('foo/bar.R')]8;; to accept the change.
  * Run ]8;;ide:run:testthat::snapshot_review('foo/bar.R')testthat::snapshot_review('foo/bar.R')]8;; to interactively review the change.

testthat documentation built on April 4, 2025, 1:08 a.m.