tests/testthat/test-combining.R

In promises: Abstractions for Promise-Based Asynchronous Programming

library(testthat)

source("common.R")

describe("promise_all", {
  it("preserves element ordering", {
    a <- resolve_later(1, 0.5)
    b <- resolve_later(2, 0.3)
    c <- resolve_later(3, 0.1)

    x <- promise_all(.list = list(a = a, b = b, c = c))
    expect_identical(extract(x), list(a = 1, b = 2, c = 3))
  })

  it("Handles NULLs correctly", {
    x <- promise_all(
      promise_resolve(NULL),
      promise_resolve(NULL),
      promise_resolve(NULL)
    )
    expect_identical(extract(x), list(NULL, NULL, NULL))

    x <- promise_all(
      a = promise_resolve(NULL),
      b = promise_resolve(NULL),
      c = promise_resolve(NULL)
    )
    expect_identical(extract(x), list(a = NULL, b = NULL, c = NULL))
  })
})