In ropenscilabs/timefuzz: Time Travel to Test Time Dependent Code

timefuzz

knitr::opts_chunk$set(
  comment = "#>",
  collapse = TRUE
)

Time travel to test time dependent code - a port of Ruby's timecop

BEWARE: VERY ALPHA

Package API:

cat(paste(" -", paste(sprintf("`%s`", getNamespaceExports("timefuzz")), collapse = "\n - ")))

Features supported:

freeze: freeze time to a specific point

Hope to support soon:

travel: travel back to a specific point in time, but allow time to continue moving forward from there
scale: scale time by a given scaling factor that will cause time to move at an accelerated pace

Installation

remotes::install_github("ropensci/timefuzz")

library("timefuzz")

freeze

freeze with a code block

library(timefuzz)
library(pendulum)
library(testthat)

book_due() is a toy function that tells us if a book is due

book_due <- function(due_date = Sys.Date() + 10) {
  sys_date() > due_date
}

Given the due date of r Sys.Date() + 10 the book is not due

expect_false(book_due()) # FALSE

Create a time_fuzz object

x <- time_fuzz$new()
x

Call freez(), passing the date you want to freeze time to, and then a code block to run in the context of that frozen time. Here we'll freeze time to today + 450 days

x$freeze(Sys.Date() + 450, {
  expect_true(book_due())
})

book_due() results in TRUE now, whereas it was FALSE above in real time

freeze without a code block

x <- time_fuzz$new()
## set to today + 450 days
x$freeze(Sys.Date() + 450)

We're in the freezed date. So any time based actions using the [pendulum][] package are now using your frozen time context.

sys_time()

call $unfreeze() to unfreeze

x$unfreeze()

now we're back in current time

sys_time()

Meta

Please report any issues or bugs.
License: MIT
Get citation information for timefuzz in R doing citation(package = 'timefuzz')
Please note that this package is released with a Contributor Code of Conduct. By contributing to this project, you agree to abide by its terms.