Test if printed output matches a target printout — expect_snapshot

This expectation can be used with tinytest to check if the new plot matches a target plot.

When the expectation is checked for the first time, the expectation fails and a reference text file is saved to the inst/tinytest/_tinysnapshot folder.

To update a snapshot, delete the reference file from the _tinysnapshot folder and run the test suite again.

See the package README file or website for detailed examples.

Usage

expect_snapshot_print(
  current,
  label,
  mode = getOption("tinysnapshot_mode", default = "unified"),
  format = getOption("tinysnapshot_format", default = "ansi256"),
  ignore_white_space = getOption("tinysnapshot_ignore_white_space", default = FALSE),
  fn_current = getOption("tinysnapshot_fn_current", default = identity),
  fn_target = getOption("tinysnapshot_fn_target", default = identity),
  ...
)

Arguments

current: an object which returns text to the console when calling print(x)`
label: a string to identify the snapshot (alpha-numeric, hyphens, or underscores). Each plot in the test suite must have a unique label.
mode: "unified", "sidebyside", "context", or "auto". See ?diffobj::diffPrint
format: "raw", "ansi8", "ansi256", "html", or "auto". See ?diffobj::diffPrint
ignore_white_space: TRUE to ignore horizontal white space and empty lines.
fn_current: A function to apply to the current output before comparison.
fn_target: A function to apply to the target output before comparison.
...: Additional arguments are passed to diffobj::diffPrint()

Value

A tinytest object. A tinytest object is a logical with attributes holding information about the test that was run