Fix a_summary() all-NA factor bug

NEWS.md

@@ -2,6 +2,7 @@
 
 ### Bug Fixes
 * Fixed bug in `tabulate_rsp_subgroups()` and `tabulate_survival_subgroups()` preventing risk difference column format specified via `control_riskdiff()` from being applied.
+* Fixed bug in `a_summary()` causing an error when all values of a factor input variable were `NA`.
 
 # tern 0.9.9
 

R/analyze_variables.R

@@ -364,7 +364,6 @@ s_summary.factor <- function(x, denom = c("n", "N_col", "N_row"), ...) {
 
   y$n_blq <- list("n_blq" = c("n_blq" = sum(grepl("BLQ|LTR|<[1-9]|<PCLLOQ", x))))
 
-
   if (isTRUE(compare_with_ref_group)) {
     .ref_group <- as_factor_keep_attributes(args_list[[".ref_group"]], verbose = verbose)
     .in_ref_col <- args_list[[".in_ref_col"]]
@@ -614,6 +613,7 @@ a_summary <- function(x,
 
   is_char <- is.character(x) || is.factor(x)
   if (is_char) {
+    x_stats <- x_stats[sapply(x_stats, \(x) length(x) > 0 || is.numeric(x))] # only return non-empty stats
     levels_per_stats <- lapply(x_stats, names)
   } else {
     levels_per_stats <- names(x_stats) %>%

tests/testthat/test-analyze_variables.R

@@ -683,3 +683,48 @@ testthat::test_that("analyze_vars warnings for geom_verbose work", {
   # Do we expect output to be NA?
   expect_true(all(is.na(cell_values(result2)[[1]])))
 })
+
+testthat::test_that("analyze_vars works with all-NA factor input", {
+  data_mtcars <- mtcars
+  data_mtcars$hp2 <- as.factor("<Missing>")
+
+  res <- basic_table() %>%
+    analyze_vars(
+      vars = c("hp2"),
+      .stats = c("n", "count_fraction", "count"),
+      na_rm = TRUE
+    ) %>%
+    build_table(data_mtcars)
+
+  expect_identical(
+    strsplit(toString(matrix_form(res), hsep = "-"), "\n")[[1]],
+    c(
+      "    all obs",
+      "-----------",
+      "n      0   "
+    )
+  )
+})
+
+testthat::test_that("analyze_vars works with all-NA character input", {
+  data_mtcars <- mtcars
+  data_mtcars$hp2 <- "<Missing>"
+
+  res <- basic_table() %>%
+    analyze_vars(
+      vars = c("hp2"),
+      .stats = c("n", "count_fraction", "count"),
+      na_rm = TRUE,
+      verbose = FALSE
+    ) %>%
+    build_table(data_mtcars)
+
+  expect_identical(
+    strsplit(toString(matrix_form(res), hsep = "-"), "\n")[[1]],
+    c(
+      "    all obs",
+      "-----------",
+      "n      0   "
+    )
+  )
+})