Disable skipping if only one snapshot left

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).
 * `test_dir()`, `test_file()`, `test_package()`, `test_check()`, `test_local()`, `source_file()` gain a `shuffle` argument uses `sample()` to randomly reorder the top-level expressions in each test file (#1942). This random reordering surfaces dependencies between tests and code outside of any test, as well as dependencies between tests. This helps you find and eliminate unintentional dependencies.
 * `snapshot_accept(test)` now works when the test file name contains `.` (#1669).
 * `local_mock()` and `with_mock()` have been deprecated because they are no longer permitted in R 4.5.

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)) {