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Merged
merged 2 commits into from
Oct 6, 2025
Merged

Improve show_text() #2257

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eb71d54
Improve `show_text()`
hadley Oct 6, 2025
f9f6600
Tweak sig
hadley Oct 6, 2025
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22 changes: 12 additions & 10 deletions R/expect-match.R
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Original file line number Diff line number Diff line change
Expand Up @@ -144,18 +144,15 @@ expect_match_ <- function(
}

# Adapted from print.ellmer_prompt
show_text <- function(
x,
condition,
...,
max_items = 20,
max_lines = max_items * 25
) {
show_text <- function(x, matches = NULL, max_items = 20, max_lines = NULL) {
matches <- matches %||% rep(TRUE, length(x))
max_lines <- max_lines %||% (max_items * 25)

n <- length(x)
n_extra <- length(x) - max_items
if (n_extra > 0) {
x <- x[seq_len(max_items)]
condition <- condition[seq_len(max_items)]
matches <- matches[seq_len(max_items)]
}

if (length(x) == 0) {
Expand All @@ -165,7 +162,7 @@ show_text <- function(
bar <- if (cli::is_utf8_output()) "\u2502" else "|"

id <- ifelse(
condition,
matches,
cli::col_green(cli::symbol$tick),
cli::col_red(cli::symbol$cross)
)
Expand All @@ -178,10 +175,15 @@ show_text <- function(
x <- gsub("\n", paste0("\n", exdent), x)

lines <- strsplit(x, "\n")
ids <- rep(seq_along(x), length(lines))
ids <- rep(seq_along(x), lengths(lines))
first <- c(TRUE, ids[-length(ids)] != ids[-1])
lines <- unlist(lines)

if (length(lines) > max_lines) {
if (first[max_lines + 1]) {
max_lines <- max_lines - 1
}
Comment on lines +183 to +185
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I might be misreading this, but I would have expected

Suggested change
if (first[max_lines + 1]) {
max_lines <- max_lines - 1
}
if (first[max_lines]) {
max_lines <- max_lines - 1
}

to avoid output like this (assuming max_lines = 2)

[1] | x
    | y
[2] | ...
... and 1 more.

i.e. I was thinking this we'd prefer to show an item only if you see at least one line, e.g.

[1] | x
    | y
... and 2 more.

whereas using first[max_lines + 1] gives

[1] | x
    | ...
... and 2 more

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ohhh, I worked it out. + 1 is right

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😅


lines <- lines[seq_len(max_lines)]
lines <- c(lines, paste0(exdent, "..."))
n_extra <- n - ids[max_lines - 1]
Expand Down
43 changes: 43 additions & 0 deletions tests/testthat/_snaps/expect-match.md
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Original file line number Diff line number Diff line change
Expand Up @@ -149,3 +149,46 @@
Actual text:
x | test

# show_text() shows success and failure

Code
base::writeLines(show_text(c("a", "b"), c(TRUE, FALSE)))
Output
✔ │ a
✖ │ b

# show_text() truncates values and lines

Code
base::writeLines(show_text(lines, max_lines = 3))
Output
✔ │ a
│ b
│ ...
... and 8 more.

Code
base::writeLines(show_text(lines, max_items = 3))
Output
✔ │ a
│ b
│ c
✔ │ d
│ e
│ f
✔ │ g
│ h
│ i
... and 6 more.

Code
base::writeLines(show_text(lines, max_items = 2, max_lines = 4))
Output
✔ │ a
│ b
│ c
✔ │ d
│ ...
... and 8 more.


24 changes: 24 additions & 0 deletions tests/testthat/test-expect-match.R
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Original file line number Diff line number Diff line change
Expand Up @@ -66,3 +66,27 @@ test_that("expect_no_match works", {
test_that("empty string is never a match", {
expect_success(expect_no_match(character(), "x"))
})

# show_text() ------------------------------------------------------------------

test_that("show_text() shows success and failure", {
local_reproducible_output(unicode = TRUE)
expect_snapshot({
base::writeLines(show_text(c("a", "b"), c(TRUE, FALSE)))
})
})

test_that("show_text() truncates values and lines", {
local_reproducible_output(unicode = TRUE)
lines <- map_chr(
split(letters, (seq_along(letters) - 1) %/% 3),
paste,
collapse = "\n"
)

expect_snapshot({
base::writeLines(show_text(lines, max_lines = 3))
base::writeLines(show_text(lines, max_items = 3))
base::writeLines(show_text(lines, max_items = 2, max_lines = 4))
})
})