tests/testthat/test-wideToLong.R

In lsr: Companion to "Learning Statistics with R"

# Outcome measure is mean response time (MRT), measured in two conditions
# with 4 participants. All participants participate in both conditions.

wide <- data.frame( accuracy_t1 = c( .15,.50,.78,.55 ),  # accuracy at time point 1
                    accuracy_t2 = c( .55,.32,.99,.60 ),  # accuracy at time point 2
                    id = 1:4 )                           # id variable



# A more complex design with multiple within-subject factors. Again, we have only
# four participants, but now we have two different outcome measures, mean response
# time (MRT) and the proportion of correct responses (PC). Additionally, we have two
# different repeated measures variables. As before, we have the experimental condition
# (cond1, cond2), but this time each participant does both conditions on two different
# days (day1, day2). Finally, we have multiple between-subject variables too, namely
# id and gender.

wide2 <- data.frame( id = 1:4,
                     gender = factor( c("male","male","female","female") ),
                     MRT_cond1_day1 = c( 415,500,478,550 ),
                     MRT_cond2_day1 = c( 455,532,499,602 ),
                     MRT_cond1_day2 = c( 400,490,468,502 ),
                     MRT_cond2_day2 = c( 450,518,474,588 ),
                     PC_cond1_day1 = c( 79,83,91,75 ),
                     PC_cond2_day1 = c( 82,86,90,78 ),
                     PC_cond1_day2 = c( 88,92,98,89 ),
                     PC_cond2_day2 = c( 93,97,100,95 ) )


test_that("wideToLong example works", {

  # convert to long form
  w1 <- wideToLong(wide, "time")
  expect_s3_class(w1, "data.frame")
  expect_equal(nrow(w1), 8)
  expect_named(w1, c("id", "time", "accuracy"))

  # conversion to long form:
  w2 <- wideToLong(wide2)
  expect_s3_class(w2, "data.frame")
  expect_equal(nrow(w2), 16)
  expect_named(w2, c("id", "gender", "MRT", "PC", "within1", "within2"))

  w3 <- wideToLong(wide2, within = c("condition","day"))
  expect_s3_class(w3, "data.frame")
  expect_equal(nrow(w3), 16)
  expect_named(w3, c("id", "gender", "MRT", "PC", "condition", "day"))

  expect_equal(unname(w2), unname(w3))

  # treat "condition x day" as a single repeated measures variable:
  w4 <- wideToLong(wide2, split = FALSE)

  expect_s3_class(w4, "data.frame")
  expect_equal(nrow(w4), 16)
  expect_named(w4, c("id", "gender", "within", "MRT", "PC"))

})