Enhance input validation for codings in FhirResource

- Added checks to ensure that `codings` and `coding` parameters are lists of lists, providing clear error messages when validation fails.
- Updated tests to validate the new input requirements for `resolve_batch` and `resolve_codeable_concept` methods, ensuring robustness against incorrect input formats.

Author: alex-omophub

R/fhir.R

@@ -92,6 +92,13 @@ FhirResource <- R6::R6Class(
                              recommendations_limit = 5L,
                              include_quality = FALSE) {
       stopifnot(is.list(codings), length(codings) >= 1, length(codings) <= 100)
+      if (!all(vapply(codings, is.list, logical(1)))) {
+        cli::cli_abort(c(
+          "{.arg codings} must be a list of coding lists.",
+          "i" = "Each element should be a list with {.field system}, {.field code}, etc.",
+          "i" = "Example: {.code list(list(system = \"http://snomed.info/sct\", code = \"44054006\"))}"
+        ))
+      }
 
       body <- list(codings = codings)
       if (!is.null(resource_type)) body$resource_type <- resource_type
@@ -127,6 +134,13 @@ FhirResource <- R6::R6Class(
                                         recommendations_limit = 5L,
                                         include_quality = FALSE) {
       stopifnot(is.list(coding), length(coding) >= 1, length(coding) <= 20)
+      if (!all(vapply(coding, is.list, logical(1)))) {
+        cli::cli_abort(c(
+          "{.arg coding} must be a list of coding lists.",
+          "i" = "Each element should be a list with {.field system} and {.field code}.",
+          "i" = "Example: {.code list(list(system = \"http://snomed.info/sct\", code = \"44054006\"))}"
+        ))
+      }
 
       body <- list(coding = coding)
       if (!is.null(text)) body$text <- text

tests/testthat/test-fhir.R

@@ -203,6 +203,28 @@ test_that("fhir$resolve_batch validates codings length", {
   expect_error(resource$resolve_batch(list()))
 })
 
+test_that("fhir$resolve_batch rejects a single coding (not list-of-lists)", {
+  base_req <- httr2::request("https://api.omophub.com/v1")
+  resource <- FhirResource$new(base_req)
+
+  # A single coding object (not wrapped in an outer list) should fail
+  expect_error(
+    resource$resolve_batch(list(system = "http://snomed.info/sct", code = "44054006")),
+    "list of coding lists"
+  )
+})
+
+test_that("fhir$resolve_codeable_concept rejects a single coding (not list-of-lists)", {
+  base_req <- httr2::request("https://api.omophub.com/v1")
+  resource <- FhirResource$new(base_req)
+
+  # A single coding object (not wrapped in an outer list) should fail
+  expect_error(
+    resource$resolve_codeable_concept(list(system = "http://snomed.info/sct", code = "44054006")),
+    "list of coding lists"
+  )
+})
+
 # ==============================================================================
 # resolve_codeable_concept()
 # ==============================================================================