Improve review UI (#2174)

* Add a reject button
* Only display file nav + skip button if multiple files to review

Fixes #2025

Author: hadley

NEWS.md

@@ -1,5 +1,6 @@
 # testthat (development version)
 
+* `snapshot_review()` includes a reject button and only displays the file navigation and the skip button if there are multiple files to review (#2025).
 * New `snapshot_download_gh()` makes it easy to get snapshots off GitHub and into your local package (#1779).
 * New `local_mocked_s3_method()`, `local_mocked_s4_method()`, and `local_mocked_r6_class()` allow you to mock S3 and S4 methods and R6 classes (#1892, #1916)
 * `expect_snapshot_file(name=)` must have a unique file path. If a snapshot file attempts to be saved with a duplicate `name`, an error will be thrown. (#1592)

R/snapshot-manage.R

@@ -73,15 +73,16 @@ review_app <- function(name, old_path, new_path, ...) {
   ui <- shiny::fluidPage(
     style = "margin: 0.5em",
     shiny::fluidRow(
-      style = "display: flex",
+      style = "display: flex; margin-bottom: 0.5em",
       shiny::div(
         style = "flex: 1 1",
-        shiny::selectInput("cases", NULL, case_index, width = "100%")
+        if (n > 1) shiny::selectInput("cases", NULL, case_index, width = "100%")
       ),
       shiny::div(
         class = "btn-group",
         style = "margin-left: 1em; flex: 0 0 auto",
-        shiny::actionButton("skip", "Skip"),
+        shiny::actionButton("reject", "Reject", class = "btn-danger"),
+        if (n > 1) shiny::actionButton("skip", "Skip"),
         shiny::actionButton("accept", "Accept", class = "btn-success"),
       )
     ),
@@ -90,11 +91,14 @@ review_app <- function(name, old_path, new_path, ...) {
     )
   )
   server <- function(input, output, session) {
-    i <- shiny::reactive(as.numeric(input$cases))
+    i <- shiny::reactive(if (n == 1) 1L else as.numeric(input$cases))
     output$diff <- diffviewer::visual_diff_render({
       diffviewer::visual_diff(old_path[[i()]], new_path[[i()]])
     })
 
+    # Can't skip if there's only one file to review
+    shiny::updateActionButton(session, "skip", disabled = (n <= 1))
+
     # Handle buttons - after clicking update move input$cases to next case,
     # and remove current case (for accept/reject). If no cases left, close app
     shiny::observeEvent(input$reject, {
@@ -122,6 +126,10 @@ review_app <- function(name, old_path, new_path, ...) {
         choices = case_index[!handled],
         selected = i
       )
+
+      n_left <- sum(!handled)
+      # Disable skip button if only one case remains
+      shiny::updateActionButton(session, "skip", disabled = (n_left <= 1))
     }
     next_case <- function() {
       if (all(handled)) {