add validation check and test if SUVR negative or zero

Author: khatril

NEWS.md

@@ -1,6 +1,6 @@
 # admiralneuro (development version)
 
-##  Updates of Existing Functions
+## Updates of Existing Functions
 
 - Improved test coverage in `compute_centiloid()` function when invalid tracer combination is provided. (#106)
 ## New features

R/compute_centiloid.R

@@ -33,7 +33,7 @@
 #'
 #' @param suvr SUVR value
 #'
-#'   A numeric value is expected.
+#'   A positive numeric value is expected.
 #'
 #' @permitted [num_scalar]
 #'
@@ -136,6 +136,11 @@ compute_centiloid <- function(
   custom_slope = NULL,
   custom_intercept = NULL
 ) {
+  # Validation check SUVR must be positive
+  if (suvr <= 0) {
+    cli::cli_abort("{.arg suvr} must be a positive numeric value (received {.val {suvr}}).")
+  }
+
   # Check custom_slope and custom_intercept
   has_custom_slope <- !is.null(custom_slope)
   has_custom_intercept <- !is.null(custom_intercept)

tests/testthat/_snaps/compute_centiloid.md

@@ -49,3 +49,11 @@
     * pipeline = "AVID FBB SUVR PIPELINE"
     * ref_region = "Whole Cerebellum"
 
+# Test 16 compute_centiloid throws error for non-positive SUVR values
+
+    `suvr` must be a positive numeric value (received 0).
+
+---
+
+    `suvr` must be a positive numeric value (received -1.5).
+

tests/testthat/test-compute_centiloid.R

@@ -207,7 +207,30 @@ test_that("Test 15 compute_centiloid() throws the expected error message when no
     compute_centiloid(
       tracer = "18F-Florbetapir",
       pipeline = "AVID FBB SUVR PIPELINE",
-      ref_region = "Whole Cerebellum"
+      ref_region = "Whole Cerebellum",
+      suvr = 1.25
+    )
+  )
+})
+
+test_that("Test 16 compute_centiloid throws error for non-positive SUVR values", {
+  # Test with zero
+  expect_snapshot_error(
+    compute_centiloid(
+      tracer = "18F-Florbetapir",
+      pipeline = "AVID FBP SUVR PIPELINE",
+      ref_region = "Whole Cerebellum",
+      suvr = 0
+    )
+  )
+
+  # Test with negative value
+  expect_snapshot_error(
+    compute_centiloid(
+      tracer = "18F-Florbetapir",
+      pipeline = "AVID FBP SUVR PIPELINE",
+      ref_region = "Whole Cerebellum",
+      suvr = -1.5
     )
   )
 })