tests/testthat/test-counterfactuals.R

In cfid: Identification of Counterfactual Queries in Causal Models

# Counterfactual variables ------------------------------------------------

test_that("unnamed interventions fail", {
  expect_error(
    cf("Y", 0L, 0L),
    "Argument `sub` must be a named integer vector"
  )
})

test_that("variable format is correct", {
  expect_identical(format(cf("Y")), "Y")
  expect_identical(format(cf("Y", 0L)), "y")
  expect_identical(format(cf("Y", 0L, c("X" = 0L))), "y_{x}")
  expect_identical(format(cf("Y", 1L, c("X" = 0L))), "y'_{x}")
  expect_identical(format(cf("Y", sub = c("X" = 0L))), "Y_{x}")
  expect_identical(format(cf("Y", sub = c("X" = 1L))), "Y_{x'}")
  expect_identical(
    format(cf("Y", 1, c("X" = 1)), use_primes = FALSE),
    "y^{(1)}_{x^{(1)}}"
  )
})

test_that("variable printing works", {
  expect_output(print(cf("Y")), "Y")
})

# Counterfactual conjunctions ---------------------------------------------

v1 <- cf("Y", 0)
v2 <- cf("X", 0)
c1 <- conj(v1, v2)

test_that("non-counterfactual variables to conjunction fails", {
  expect_error(
    conj(v1, "X"),
    "All arguments must be `counterfactual_variable` object."
  )
})

test_that("list coercion is supported", {
  expect_identical(as.counterfactual_conjunction(list(v1, v2)), c1)
})

test_that("default coercion is supported for conjunctions", {
  expect_identical(as.counterfactual_conjunction(c1), c1)
  expect_error(
    as.counterfactual_conjunction(0L),
    "Cannot coerce object to class `counterfactual_conjunction`"
  )
})

test_that("conjunction format is correct", {
  expect_identical(format(c1), "y /\\ x")
})

test_that("conjunction printing works", {
  expect_output(print(c1), "y /\\\\ x")
})

test_that("counterfactual arithmetic is correct", {
  expect_identical(v1 + v2, c1)
  expect_identical(conj(v1) + v2, c1)
  expect_identical(v1 + conj(v2), c1)
  expect_identical(conj(v1) + conj(v2), c1)
  expect_identical(v1 + v1, conj(v1))
  expect_identical(c1 + v1, c1)
  expect_identical(v1 + c1, c1)
  expect_error(
    v1 + "Y",
    "Cannot add an object of class `character` to a counterfactual variable"
  )
  expect_error(
    c1 + "Y",
    "Cannot add an object of class `character` to a counterfactual conjunction"
  )
  expect_error(
    `+.counterfactual_conjunction`("X", "Y"),
    "Unsupported input for method"
  )
})

# Conflicts ---------------------------------------------------------------

test_that("produces conflicts", {
  v1 <- cf("Y", 0, c(X = 0))
  v2 <- cf("Y", 1, c(X = 0))
  v3 <- cf("Y", 0, c(X = 1))
  v4 <- cf("Y", 1, c(X = 1))
  expect_length(trivial_conflict(v1, list(v2, v3)), 1)
  expect_length(trivial_conflicts(list(v1, v2, v3, v4)), 2)
  expect_error(check_conflicts(v1, list(v2, v3)))
})

# Value extraction --------------------------------------------------------

test_that("both obs and int values received", {
  v1 <- cf("Y", 0, c(X = 1, Z = 0))
  v2 <- cf("X", 1, c(W = 2, Z = 0))
  v3 <- list(var = "X", sub = c(W = 1))
  expect_identical(
    evs(list(v1, v2, v3)),
    list(
      c(Y = 0L, X = 1L, Z = 0L),
      c(X = 1L, W = 2L, Z = 0L),
      c(W = 1)
    )
  )
})