test_that("lead and lag preserve factors", {
x <- factor(c("a", "b", "c"))
expect_equal(levels(lead(x)), c("a", "b", "c"))
expect_equal(levels(lag(x)), c("a", "b", "c"))
})
test_that("lead and lag preserves dates and times", {
x <- as.Date("2013-01-01") + 1:3
y <- as.POSIXct(x)
expect_s3_class(lead(x), "Date")
expect_s3_class(lag(x), "Date")
expect_s3_class(lead(y), "POSIXct")
expect_s3_class(lag(y), "POSIXct")
})
test_that("#925 is fixed", {
data <- tibble(
name = c("Rob", "Pete", "Rob", "John", "Rob", "Pete", "John", "Pete", "John", "Pete", "Rob", "Rob"),
time = c(3, 2, 5, 3, 2, 3, 2, 4, 1, 1, 4, 1)
)
res <- data %>% group_by(name) %>% mutate(lag_time = lag(time))
expect_equal(
res$lag_time[res$name == "Rob"],
c(NA, head(data$time[data$name == "Rob"], -1))
)
expect_equal(
res$lag_time[res$name == "Pete"],
c(NA, head(data$time[data$name == "Pete"], -1))
)
expect_equal(
res$lag_time[res$name == "John"],
c(NA, head(data$time[data$name == "John"], -1))
)
})
test_that("#937 is fixed", {
df <- tibble(
name = rep(c("Al", "Jen"), 3),
score = rep(c(100, 80, 60), 2)
)
res <- df %>% group_by(name) %>% mutate(next.score = lead(score))
expect_equal(
res$next.score[res$name == "Al"],
c(tail(df$score[df$name == "Al"], -1), NA)
)
expect_equal(
res$next.score[res$name == "Jen"],
c(tail(df$score[df$name == "Jen"], -1), NA)
)
})
test_that("lead() and lag() work for matrices (#5028)", {
m <- matrix(1:6, ncol = 2)
expect_equal(lag(m, 1), matrix(c(NA_integer_, 1L, 2L, NA_integer_, 4L, 5L), ncol = 2))
expect_equal(lag(m, 1, default = NA), matrix(c(NA_integer_, 1L, 2L, NA_integer_, 4L, 5L), ncol= 2))
expect_equal(lead(m, 1), matrix(c(2L, 3L, NA_integer_, 5L, 6L, NA_integer_), ncol = 2))
expect_equal(lead(m, 1, default = NA), matrix(c(2L, 3L, NA_integer_, 5L, 6L, NA_integer_), ncol = 2))
})
test_that("lead() and lag() checks size of default (#5641)", {
expect_error(lead(1:10, default = integer()))
expect_error(lag(1:10, default = integer()))
})
# Errors ------------------------------------------------------------------
test_that("lead() / lag() give meaningful errors", {
expect_snapshot({
"# complicance of n argument"
(expect_error(lead(letters, -1)))
(expect_error(lead(letters, "1")))
(expect_error(lag(letters, -1)))
(expect_error(lag(letters, "1")))
"# ts"
(expect_error(lag(ts(1:10))))
"# incompatible default"
(expect_error(lag(c("1", "2", "3"), default = FALSE)))
(expect_error(lead(c("1", "2", "3"), default = FALSE)))
(expect_error(lag(c("1", "2", "3"), default = character())))
(expect_error(lead(c("1", "2", "3"), default = character())))
})
})
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