diff --git a/modules/openapi-generator/src/main/resources/r/api.mustache b/modules/openapi-generator/src/main/resources/r/api.mustache
index b3057454cdb..a32d43ba2e6 100644
--- a/modules/openapi-generator/src/main/resources/r/api.mustache
+++ b/modules/openapi-generator/src/main/resources/r/api.mustache
@@ -271,7 +271,9 @@
       if (httr::status_code(resp) >= 200 && httr::status_code(resp) <= 299) {
         {{#returnType}}
         {{#isPrimitiveType}}
-        content <- httr::content(resp, "text", encoding = "UTF-8")
+        content <- httr::content(
+            resp, "text", encoding = "UTF-8", simplifyVector = FALSE
+        )
         ApiResponse$new(content,resp)
         {{/isPrimitiveType}}
         {{^isPrimitiveType}}
diff --git a/modules/openapi-generator/src/main/resources/r/api_client.mustache b/modules/openapi-generator/src/main/resources/r/api_client.mustache
index 22fd994ab64..8a403315fa1 100644
--- a/modules/openapi-generator/src/main/resources/r/api_client.mustache
+++ b/modules/openapi-generator/src/main/resources/r/api_client.mustache
@@ -166,7 +166,9 @@ ApiClient  <- R6::R6Class(
       else if (exists(returnType, pkgEnv) && !(c(returnType) %in% primitiveTypes)) {
         returnType <- get(returnType, envir = as.environment(pkgEnv))
         returnObj <- returnType$new()
-        returnObj$fromJSON(jsonlite::toJSON(obj, digits = NA))
+        returnObj$fromJSON(
+          jsonlite::toJSON(obj, digits = NA, auto_unbox = TRUE)
+        )
       } 
 
       # To handle primitive type
diff --git a/modules/openapi-generator/src/main/resources/r/api_test.mustache b/modules/openapi-generator/src/main/resources/r/api_test.mustache
index 6b0bbcf8716..1b7e184d85f 100644
--- a/modules/openapi-generator/src/main/resources/r/api_test.mustache
+++ b/modules/openapi-generator/src/main/resources/r/api_test.mustache
@@ -17,7 +17,7 @@ test_that("{{{operationId}}}", {
   # {{notes}}
   {{/notes}}
 {{#allParams}}
-  # @param {{{dataType}}}  {{{paramName}}}  {{{description}}} {{^required}} (optional){{/required}}
+  # @param {{{paramName}}} {{{dataType}}} {{{description}}}{{^required}} (optional){{/required}}
 {{/allParams}}
   # @return [{{#returnType}}{{{returnType}}}{{/returnType}}{{^returnType}}Void{{/returnType}}]
 
diff --git a/modules/openapi-generator/src/main/resources/r/model.mustache b/modules/openapi-generator/src/main/resources/r/model.mustache
index bf04a122144..aba9d1b987b 100644
--- a/modules/openapi-generator/src/main/resources/r/model.mustache
+++ b/modules/openapi-generator/src/main/resources/r/model.mustache
@@ -3,15 +3,21 @@
 {{>partial_header}}
 #' @docType class
 #' @title {{classname}}
+#'
 #' @description {{classname}} Class
+#'
 #' @format An \code{R6Class} generator object
+#'
 {{#vars}}
 #' @field {{baseName}} {{title}} {{#isContainer}}{{#isListContainer}}list( {{/isListContainer}}{{#isMapContainer}}named list( {{/isMapContainer}}{{/isContainer}}{{^isPrimitiveType}}\link{{=<% %>=}}{<%/isPrimitiveType%><%={{ }}=%>{{#isContainer}}{{#items}}{{dataType}}{{/items}}{{/isContainer}}{{^isContainer}}{{dataType}}{{/isContainer}}{{=<% %>=}}<%^isPrimitiveType%>}<%={{ }}=%>{{/isPrimitiveType}}{{#isContainer}}{{#isListContainer}} ){{/isListContainer}}{{#isMapContainer}} ){{/isMapContainer}}{{/isContainer}} {{^required}}[optional]{{/required}}
 #'
 {{/vars}}
-#'
 #' @importFrom R6 R6Class
 #' @importFrom jsonlite fromJSON toJSON
+{{#isEnum}}
+{{>modelEnum}}
+{{/isEnum}}
+{{^isEnum}}
 #' @export
 {{classname}} <- R6::R6Class(
   '{{classname}}',
@@ -19,7 +25,9 @@
     {{#vars}}
     `{{{baseName}}}` = NULL,
     {{/vars}}
-    initialize = function({{#requiredVars}}`{{baseName}}`{{#hasMore}}, {{/hasMore}}{{/requiredVars}}{{#optionalVars}}{{#-first}}{{#requiredVars.0}}, {{/requiredVars.0}}{{/-first}}`{{baseName}}`={{#defaultValue}}{{{.}}}{{/defaultValue}}{{^defaultValue}}NULL{{/defaultValue}}{{^-last}}, {{/-last}}{{/optionalVars}}, ...){
+    initialize = function(
+        {{#requiredVars}}`{{baseName}}`, {{/requiredVars}}{{#optionalVars}}`{{baseName}}`={{#defaultValue}}{{{.}}}{{/defaultValue}}{{^defaultValue}}NULL{{/defaultValue}}, {{/optionalVars}}...
+    ) {
       local.optional.var <- list(...)
       {{#requiredVars}}
       if (!missing(`{{baseName}}`)) {
@@ -159,6 +167,7 @@
         {{/isContainer}}
       }
       {{/vars}}
+      self
     },
     toJSONString = function() {
       jsoncontent <- c(
@@ -241,5 +250,7 @@
     }
   )
 )
+{{/isEnum}}
 {{/model}}
 {{/models}}
+
diff --git a/modules/openapi-generator/src/main/resources/r/modelEnum.mustache b/modules/openapi-generator/src/main/resources/r/modelEnum.mustache
new file mode 100644
index 00000000000..c648c0365fc
--- /dev/null
+++ b/modules/openapi-generator/src/main/resources/r/modelEnum.mustache
@@ -0,0 +1,48 @@
+#' @export
+{{#allowableValues}}
+{{classname}} <- R6::R6Class(
+    "{{classname}}",
+    public = list(
+        initialize = function(...) {
+            local.optional.var <- list(...)
+            val <- unlist(local.optional.var)
+            enumvec <- .parse_{{name}}()
+
+            stopifnot(length(val) == 1L)
+
+            if (!val %in% enumvec)
+                stop("Use one of the valid values: ",
+                    paste0(enumvec, collapse = ", "))
+            private$value <- val
+        },
+        toJSON = function() {
+            jsonlite::toJSON(private$value, auto_unbox = TRUE)
+        },
+        fromJSON = function({{classname}}Json) {
+            private$value <- jsonlite::fromJSON({{classname}}Json,
+                simplifyVector = FALSE)
+            self
+        },
+        toJSONString = function() {
+            as.character(jsonlite::toJSON(private$value,
+                auto_unbox = TRUE))
+        },
+        fromJSONString = function({{classname}}Json) {
+            private$value <- jsonlite::fromJSON({{classname}}Json,
+                simplifyVector = FALSE)
+            self
+        }
+    ),
+    private = list(
+        value = NULL
+    )
+)
+
+# add to utils.R
+.parse_{{name}} <- function(vals) {
+    res <- gsub("^\\[|\\]$", "",
+        "{{{values}}}"
+    )
+    unlist(strsplit(res, ", "))
+}
+{{/allowableValues}}
diff --git a/samples/client/petstore/R/R/api_client.R b/samples/client/petstore/R/R/api_client.R
index f6b8544aacd..fe61ecfbde9 100644
--- a/samples/client/petstore/R/R/api_client.R
+++ b/samples/client/petstore/R/R/api_client.R
@@ -164,7 +164,9 @@ ApiClient  <- R6::R6Class(
       else if (exists(returnType, pkgEnv) && !(c(returnType) %in% primitiveTypes)) {
         returnType <- get(returnType, envir = as.environment(pkgEnv))
         returnObj <- returnType$new()
-        returnObj$fromJSON(jsonlite::toJSON(obj, digits = NA))
+        returnObj$fromJSON(
+          jsonlite::toJSON(obj, digits = NA, auto_unbox = TRUE)
+        )
       } 
 
       # To handle primitive type
diff --git a/samples/client/petstore/R/R/category.R b/samples/client/petstore/R/R/category.R
index 6ff2f1510cc..7c74320d1ac 100644
--- a/samples/client/petstore/R/R/category.R
+++ b/samples/client/petstore/R/R/category.R
@@ -8,13 +8,15 @@
 
 #' @docType class
 #' @title Category
+#'
 #' @description Category Class
+#'
 #' @format An \code{R6Class} generator object
+#'
 #' @field id  integer [optional]
 #'
 #' @field name  character [optional]
 #'
-#'
 #' @importFrom R6 R6Class
 #' @importFrom jsonlite fromJSON toJSON
 #' @export
@@ -23,7 +25,9 @@ Category <- R6::R6Class(
   public = list(
     `id` = NULL,
     `name` = NULL,
-    initialize = function(`id`=NULL, `name`=NULL, ...){
+    initialize = function(
+        `id`=NULL, `name`=NULL, ...
+    ) {
       local.optional.var <- list(...)
       if (!is.null(`id`)) {
         stopifnot(is.numeric(`id`), length(`id`) == 1)
@@ -55,6 +59,7 @@ Category <- R6::R6Class(
       if (!is.null(CategoryObject$`name`)) {
         self$`name` <- CategoryObject$`name`
       }
+      self
     },
     toJSONString = function() {
       jsoncontent <- c(
@@ -84,3 +89,4 @@ Category <- R6::R6Class(
     }
   )
 )
+
diff --git a/samples/client/petstore/R/R/model_api_response.R b/samples/client/petstore/R/R/model_api_response.R
index ddf573164b7..c7cdbb76c2a 100644
--- a/samples/client/petstore/R/R/model_api_response.R
+++ b/samples/client/petstore/R/R/model_api_response.R
@@ -8,15 +8,17 @@
 
 #' @docType class
 #' @title ModelApiResponse
+#'
 #' @description ModelApiResponse Class
+#'
 #' @format An \code{R6Class} generator object
+#'
 #' @field code  integer [optional]
 #'
 #' @field type  character [optional]
 #'
 #' @field message  character [optional]
 #'
-#'
 #' @importFrom R6 R6Class
 #' @importFrom jsonlite fromJSON toJSON
 #' @export
@@ -26,7 +28,9 @@ ModelApiResponse <- R6::R6Class(
     `code` = NULL,
     `type` = NULL,
     `message` = NULL,
-    initialize = function(`code`=NULL, `type`=NULL, `message`=NULL, ...){
+    initialize = function(
+        `code`=NULL, `type`=NULL, `message`=NULL, ...
+    ) {
       local.optional.var <- list(...)
       if (!is.null(`code`)) {
         stopifnot(is.numeric(`code`), length(`code`) == 1)
@@ -69,6 +73,7 @@ ModelApiResponse <- R6::R6Class(
       if (!is.null(ModelApiResponseObject$`message`)) {
         self$`message` <- ModelApiResponseObject$`message`
       }
+      self
     },
     toJSONString = function() {
       jsoncontent <- c(
@@ -106,3 +111,4 @@ ModelApiResponse <- R6::R6Class(
     }
   )
 )
+
diff --git a/samples/client/petstore/R/R/order.R b/samples/client/petstore/R/R/order.R
index a5acac3bfff..3218835cc35 100644
--- a/samples/client/petstore/R/R/order.R
+++ b/samples/client/petstore/R/R/order.R
@@ -8,8 +8,11 @@
 
 #' @docType class
 #' @title Order
+#'
 #' @description Order Class
+#'
 #' @format An \code{R6Class} generator object
+#'
 #' @field id  integer [optional]
 #'
 #' @field petId  integer [optional]
@@ -22,7 +25,6 @@
 #'
 #' @field complete  character [optional]
 #'
-#'
 #' @importFrom R6 R6Class
 #' @importFrom jsonlite fromJSON toJSON
 #' @export
@@ -35,7 +37,9 @@ Order <- R6::R6Class(
     `shipDate` = NULL,
     `status` = NULL,
     `complete` = NULL,
-    initialize = function(`id`=NULL, `petId`=NULL, `quantity`=NULL, `shipDate`=NULL, `status`=NULL, `complete`=FALSE, ...){
+    initialize = function(
+        `id`=NULL, `petId`=NULL, `quantity`=NULL, `shipDate`=NULL, `status`=NULL, `complete`=FALSE, ...
+    ) {
       local.optional.var <- list(...)
       if (!is.null(`id`)) {
         stopifnot(is.numeric(`id`), length(`id`) == 1)
@@ -110,6 +114,7 @@ Order <- R6::R6Class(
       if (!is.null(OrderObject$`complete`)) {
         self$`complete` <- OrderObject$`complete`
       }
+      self
     },
     toJSONString = function() {
       jsoncontent <- c(
@@ -171,3 +176,4 @@ Order <- R6::R6Class(
     }
   )
 )
+
diff --git a/samples/client/petstore/R/R/pet.R b/samples/client/petstore/R/R/pet.R
index 760463d67ba..509d16934e1 100644
--- a/samples/client/petstore/R/R/pet.R
+++ b/samples/client/petstore/R/R/pet.R
@@ -8,8 +8,11 @@
 
 #' @docType class
 #' @title Pet
+#'
 #' @description Pet Class
+#'
 #' @format An \code{R6Class} generator object
+#'
 #' @field id  integer [optional]
 #'
 #' @field category  \link{Category} [optional]
@@ -22,7 +25,6 @@
 #'
 #' @field status  character [optional]
 #'
-#'
 #' @importFrom R6 R6Class
 #' @importFrom jsonlite fromJSON toJSON
 #' @export
@@ -35,7 +37,9 @@ Pet <- R6::R6Class(
     `photoUrls` = NULL,
     `tags` = NULL,
     `status` = NULL,
-    initialize = function(`name`, `photoUrls`, `id`=NULL, `category`=NULL, `tags`=NULL, `status`=NULL, ...){
+    initialize = function(
+        `name`, `photoUrls`, `id`=NULL, `category`=NULL, `tags`=NULL, `status`=NULL, ...
+    ) {
       local.optional.var <- list(...)
       if (!missing(`name`)) {
         stopifnot(is.character(`name`), length(`name`) == 1)
@@ -115,6 +119,7 @@ Pet <- R6::R6Class(
       if (!is.null(PetObject$`status`)) {
         self$`status` <- PetObject$`status`
       }
+      self
     },
     toJSONString = function() {
       jsoncontent <- c(
@@ -176,3 +181,4 @@ Pet <- R6::R6Class(
     }
   )
 )
+
diff --git a/samples/client/petstore/R/R/tag.R b/samples/client/petstore/R/R/tag.R
index 5644807f5c6..56b89c6b425 100644
--- a/samples/client/petstore/R/R/tag.R
+++ b/samples/client/petstore/R/R/tag.R
@@ -8,13 +8,15 @@
 
 #' @docType class
 #' @title Tag
+#'
 #' @description Tag Class
+#'
 #' @format An \code{R6Class} generator object
+#'
 #' @field id  integer [optional]
 #'
 #' @field name  character [optional]
 #'
-#'
 #' @importFrom R6 R6Class
 #' @importFrom jsonlite fromJSON toJSON
 #' @export
@@ -23,7 +25,9 @@ Tag <- R6::R6Class(
   public = list(
     `id` = NULL,
     `name` = NULL,
-    initialize = function(`id`=NULL, `name`=NULL, ...){
+    initialize = function(
+        `id`=NULL, `name`=NULL, ...
+    ) {
       local.optional.var <- list(...)
       if (!is.null(`id`)) {
         stopifnot(is.numeric(`id`), length(`id`) == 1)
@@ -55,6 +59,7 @@ Tag <- R6::R6Class(
       if (!is.null(TagObject$`name`)) {
         self$`name` <- TagObject$`name`
       }
+      self
     },
     toJSONString = function() {
       jsoncontent <- c(
@@ -84,3 +89,4 @@ Tag <- R6::R6Class(
     }
   )
 )
+
diff --git a/samples/client/petstore/R/R/user.R b/samples/client/petstore/R/R/user.R
index 2afd3de04c6..bf88bee4027 100644
--- a/samples/client/petstore/R/R/user.R
+++ b/samples/client/petstore/R/R/user.R
@@ -8,8 +8,11 @@
 
 #' @docType class
 #' @title User
+#'
 #' @description User Class
+#'
 #' @format An \code{R6Class} generator object
+#'
 #' @field id  integer [optional]
 #'
 #' @field username  character [optional]
@@ -26,7 +29,6 @@
 #'
 #' @field userStatus  integer [optional]
 #'
-#'
 #' @importFrom R6 R6Class
 #' @importFrom jsonlite fromJSON toJSON
 #' @export
@@ -41,7 +43,9 @@ User <- R6::R6Class(
     `password` = NULL,
     `phone` = NULL,
     `userStatus` = NULL,
-    initialize = function(`id`=NULL, `username`=NULL, `firstName`=NULL, `lastName`=NULL, `email`=NULL, `password`=NULL, `phone`=NULL, `userStatus`=NULL, ...){
+    initialize = function(
+        `id`=NULL, `username`=NULL, `firstName`=NULL, `lastName`=NULL, `email`=NULL, `password`=NULL, `phone`=NULL, `userStatus`=NULL, ...
+    ) {
       local.optional.var <- list(...)
       if (!is.null(`id`)) {
         stopifnot(is.numeric(`id`), length(`id`) == 1)
@@ -139,6 +143,7 @@ User <- R6::R6Class(
       if (!is.null(UserObject$`userStatus`)) {
         self$`userStatus` <- UserObject$`userStatus`
       }
+      self
     },
     toJSONString = function() {
       jsoncontent <- c(
@@ -216,3 +221,4 @@ User <- R6::R6Class(
     }
   )
 )
+
diff --git a/samples/client/petstore/R/tests/testthat/test_order.R b/samples/client/petstore/R/tests/testthat/test_order.R
index 5fb144f9372..33b87520254 100644
--- a/samples/client/petstore/R/tests/testthat/test_order.R
+++ b/samples/client/petstore/R/tests/testthat/test_order.R
@@ -12,11 +12,11 @@ test_that("id", {
   #expect_equal(model.instance$`id`, "EXPECTED_RESULT")
 })
 
-test_that("pet_id", {
-  # tests for the property `pet_id` (integer)
+test_that("petId", {
+  # tests for the property `petId` (integer)
 
   # uncomment below to test the property 
-  #expect_equal(model.instance$`pet_id`, "EXPECTED_RESULT")
+  #expect_equal(model.instance$`petId`, "EXPECTED_RESULT")
 })
 
 test_that("quantity", {
@@ -26,11 +26,11 @@ test_that("quantity", {
   #expect_equal(model.instance$`quantity`, "EXPECTED_RESULT")
 })
 
-test_that("ship_date", {
-  # tests for the property `ship_date` (character)
+test_that("shipDate", {
+  # tests for the property `shipDate` (character)
 
   # uncomment below to test the property 
-  #expect_equal(model.instance$`ship_date`, "EXPECTED_RESULT")
+  #expect_equal(model.instance$`shipDate`, "EXPECTED_RESULT")
 })
 
 test_that("status", {
diff --git a/samples/client/petstore/R/tests/testthat/test_pet.R b/samples/client/petstore/R/tests/testthat/test_pet.R
index 8d3ce54a55d..ac3e4f31dd1 100644
--- a/samples/client/petstore/R/tests/testthat/test_pet.R
+++ b/samples/client/petstore/R/tests/testthat/test_pet.R
@@ -26,15 +26,15 @@ test_that("name", {
   #expect_equal(model.instance$`name`, "EXPECTED_RESULT")
 })
 
-test_that("photo_urls", {
-  # tests for the property `photo_urls` (character)
+test_that("photoUrls", {
+  # tests for the property `photoUrls` (array[character])
 
   # uncomment below to test the property 
-  #expect_equal(model.instance$`photo_urls`, "EXPECTED_RESULT")
+  #expect_equal(model.instance$`photoUrls`, "EXPECTED_RESULT")
 })
 
 test_that("tags", {
-  # tests for the property `tags` (Tag)
+  # tests for the property `tags` (array[Tag])
 
   # uncomment below to test the property 
   #expect_equal(model.instance$`tags`, "EXPECTED_RESULT")
diff --git a/samples/client/petstore/R/tests/testthat/test_pet_api.R b/samples/client/petstore/R/tests/testthat/test_pet_api.R
index 021f6228af9..7fbdd1a70de 100644
--- a/samples/client/petstore/R/tests/testthat/test_pet_api.R
+++ b/samples/client/petstore/R/tests/testthat/test_pet_api.R
@@ -7,9 +7,9 @@ api.instance <- PetApi$new()
 
 test_that("AddPet", {
   # tests for AddPet
+  # base path: http://petstore.swagger.io/v2
   # Add a new pet to the store
-  # @param body Pet object that needs to be added to the store
-  # @param [Hash] opts the optional parameters
+  # @param body Pet Pet object that needs to be added to the store
   # @return [Void]
 
   # uncomment below to test the operation
@@ -18,10 +18,10 @@ test_that("AddPet", {
 
 test_that("DeletePet", {
   # tests for DeletePet
+  # base path: http://petstore.swagger.io/v2
   # Deletes a pet
-  # @param pet.id Pet id to delete
-  # @param [Hash] opts the optional parameters
-  # @option opts [character] :api.key 
+  # @param pet.id integer Pet id to delete
+  # @param api.key character  (optional)
   # @return [Void]
 
   # uncomment below to test the operation
@@ -30,11 +30,11 @@ test_that("DeletePet", {
 
 test_that("FindPetsByStatus", {
   # tests for FindPetsByStatus
+  # base path: http://petstore.swagger.io/v2
   # Finds Pets by status
   # Multiple status values can be provided with comma separated strings
-  # @param status Status values that need to be considered for filter
-  # @param [Hash] opts the optional parameters
-  # @return [Pet]
+  # @param status array[character] Status values that need to be considered for filter
+  # @return [array[Pet]]
 
   # uncomment below to test the operation
   #expect_equal(result, "EXPECTED_RESULT")
@@ -42,11 +42,11 @@ test_that("FindPetsByStatus", {
 
 test_that("FindPetsByTags", {
   # tests for FindPetsByTags
+  # base path: http://petstore.swagger.io/v2
   # Finds Pets by tags
   # Multiple tags can be provided with comma separated strings. Use tag1, tag2, tag3 for testing.
-  # @param tags Tags to filter by
-  # @param [Hash] opts the optional parameters
-  # @return [Pet]
+  # @param tags array[character] Tags to filter by
+  # @return [array[Pet]]
 
   # uncomment below to test the operation
   #expect_equal(result, "EXPECTED_RESULT")
@@ -54,10 +54,10 @@ test_that("FindPetsByTags", {
 
 test_that("GetPetById", {
   # tests for GetPetById
+  # base path: http://petstore.swagger.io/v2
   # Find pet by ID
   # Returns a single pet
-  # @param pet.id ID of pet to return
-  # @param [Hash] opts the optional parameters
+  # @param pet.id integer ID of pet to return
   # @return [Pet]
 
   # uncomment below to test the operation
@@ -66,9 +66,9 @@ test_that("GetPetById", {
 
 test_that("UpdatePet", {
   # tests for UpdatePet
+  # base path: http://petstore.swagger.io/v2
   # Update an existing pet
-  # @param body Pet object that needs to be added to the store
-  # @param [Hash] opts the optional parameters
+  # @param body Pet Pet object that needs to be added to the store
   # @return [Void]
 
   # uncomment below to test the operation
@@ -77,11 +77,11 @@ test_that("UpdatePet", {
 
 test_that("UpdatePetWithForm", {
   # tests for UpdatePetWithForm
+  # base path: http://petstore.swagger.io/v2
   # Updates a pet in the store with form data
-  # @param pet.id ID of pet that needs to be updated
-  # @param [Hash] opts the optional parameters
-  # @option opts [character] :name Updated name of the pet
-  # @option opts [character] :status Updated status of the pet
+  # @param pet.id integer ID of pet that needs to be updated
+  # @param name character Updated name of the pet (optional)
+  # @param status character Updated status of the pet (optional)
   # @return [Void]
 
   # uncomment below to test the operation
@@ -90,11 +90,11 @@ test_that("UpdatePetWithForm", {
 
 test_that("UploadFile", {
   # tests for UploadFile
+  # base path: http://petstore.swagger.io/v2
   # uploads an image
-  # @param pet.id ID of pet to update
-  # @param [Hash] opts the optional parameters
-  # @option opts [character] :additional.metadata Additional data to pass to server
-  # @option opts [data.frame] :file file to upload
+  # @param pet.id integer ID of pet to update
+  # @param additional.metadata character Additional data to pass to server (optional)
+  # @param file data.frame file to upload (optional)
   # @return [ModelApiResponse]
 
   # uncomment below to test the operation
diff --git a/samples/client/petstore/R/tests/testthat/test_petstore.R b/samples/client/petstore/R/tests/testthat/test_petstore.R
index 2e24b32f124..941c30af7e5 100644
--- a/samples/client/petstore/R/tests/testthat/test_petstore.R
+++ b/samples/client/petstore/R/tests/testthat/test_petstore.R
@@ -1,31 +1,67 @@
 context("basic functionality")
 petApi <- PetApi$new()
 petId <- 123321
+pet <- Pet$new("name_test",
+  photoUrls = list("photo_test", "second test"),
+  category = Category$new(id=450, name="test_cat"),
+  id = petId,
+  tags = list(
+    Tag$new(id=123, name="tag_test"), Tag$new(id=456, name="unknown")
+  ),
+  status = "available"
+)
+result <- petApi$AddPet(pet)
+
 test_that("AddPet", {
-  pet <- Pet$new("name_test", list("photo_test", "second test"),
-                 petId, Category$new(id=450, name="test_cat"),
-                 list(Tag$new(id=123, name="tag_test"), Tag$new(id=456, name="unknown")), 
-                 "available")
-  #pet <- Pet$new("name_test", 
-  #               list("photo_test", "second test"),
-  #               category=Category$new(id=450, name="test_cat"),
-  #               id=petId,
-  #               tags=list(Tag$new(id=123, name="tag_test"), Tag$new(id=456, name="unknown")),
-  #               status="available")
-  result <-petApi$AddPet(pet)
   expect_equal(petId, 123321)
   expect_equal(result, NULL)
 })
 
-test_that("Test Pet", {
-  pet <- Pet$new("name_test", list("photo_test", "second test"),
-                 petId, Category$new(id=450, name="test_cat"),
-                 list(Tag$new(id=123, name="tag_test"), Tag$new(id=456, name="unknown")), 
-                 "available")
+test_that("Test toJSON toJSON fromJSON fromJSONString", {
+  pet0 <- Pet$new()
+  jsonpet <- pet0$toJSON()
+  pet2 <- pet0$fromJSON(
+    jsonlite::toJSON(jsonpet, auto_unbox=TRUE)
+  )
+  expect_equal(pet0, pet2)
+  jsonpet <- pet0$toJSONString()
+  pet2 <- pet0$fromJSON(
+    jsonpet
+  )
+  expect_equal(pet0, pet2)
 
-  pet2 <- Pet$new()
-  #pet2$fromJSON(jsonlite::toJSON(pet$toJSON(), auto_unbox=TRUE))
-  #expect_equal(pet, pet2)
+  jsonpet <- pet0$toJSONString()
+  pet2 <- pet0$fromJSONString(
+    jsonpet
+  )
+  expect_equal(pet0, pet2)
+
+  pet1 <- Pet$new("name_test",
+    list("photo_test", "second test"),
+    category = Category$new(id=450, name="test_cat"),
+    id = petId,
+    tags = list(
+      Tag$new(id=123, name="tag_test"), Tag$new(id=456, name="unknown")
+    ),
+    status = "available"
+  )
+  jsonpet <- pet1$toJSON()
+  pet2 <- pet1$fromJSON(
+    jsonlite::toJSON(jsonpet, auto_unbox=TRUE)
+  )
+  expect_equal(pet1, pet2)
+
+  jsonpet <- pet1$toJSONString()
+  pet2 <- pet1$fromJSON(
+    jsonpet
+  )
+  expect_equal(pet1, pet2)
+
+  jsonpet <- pet1$toJSONString()
+  pet2 <- pet1$fromJSONString(
+    jsonpet
+  )
+  expect_equal(pet1, pet2)
 })
 
 test_that("Test Category", {
@@ -33,16 +69,26 @@ test_that("Test Category", {
   c2 <- Category$new()
   c2$fromJSON(jsonlite::toJSON(c1$toJSON(), auto_unbox=TRUE))
   expect_equal(c1, c2)
+  c2$fromJSONString(c1$toJSONString())
+  expect_equal(c1, c2)
 })
 
 test_that("GetPetById", {
   response <- petApi$GetPetById(petId)
   expect_equal(response$id, petId)
   expect_equal(response$name, "name_test")
-  #expect_equal(response$category, Category$new(id=450, name="test_cat"))
-  expect_equal(response$photoUrls, list("photo_test", "second test"))
+  expect_equal(
+    response$photoUrls,
+    list("photo_test", "second test")
+  )
   expect_equal(response$status, "available")
-  expect_equal(response$tags, list(Tag$new(id=123, name="tag_test"), Tag$new(id=456, name="unknown")))
+  expect_equal(response$category, Category$new(id=450, name="test_cat"))
+
+  expect_equal(pet$tags, response$tags)
+  expect_equal(
+    response$tags,
+    list(Tag$new(id=123, name="tag_test"), Tag$new(id=456, name="unknown"))
+  )
 })
 
 #test_that("GetPetById", {
diff --git a/samples/client/petstore/R/tests/testthat/test_store_api.R b/samples/client/petstore/R/tests/testthat/test_store_api.R
index e1290358b43..1ebb3f82a63 100644
--- a/samples/client/petstore/R/tests/testthat/test_store_api.R
+++ b/samples/client/petstore/R/tests/testthat/test_store_api.R
@@ -7,10 +7,10 @@ api.instance <- StoreApi$new()
 
 test_that("DeleteOrder", {
   # tests for DeleteOrder
+  # base path: http://petstore.swagger.io/v2
   # Delete purchase order by ID
   # For valid response try integer IDs with value &lt; 1000. Anything above 1000 or nonintegers will generate API errors
-  # @param order.id ID of the order that needs to be deleted
-  # @param [Hash] opts the optional parameters
+  # @param order.id character ID of the order that needs to be deleted
   # @return [Void]
 
   # uncomment below to test the operation
@@ -19,10 +19,10 @@ test_that("DeleteOrder", {
 
 test_that("GetInventory", {
   # tests for GetInventory
+  # base path: http://petstore.swagger.io/v2
   # Returns pet inventories by status
   # Returns a map of status codes to quantities
-  # @param [Hash] opts the optional parameters
-  # @return [integer]
+  # @return [map(integer)]
 
   # uncomment below to test the operation
   #expect_equal(result, "EXPECTED_RESULT")
@@ -30,10 +30,10 @@ test_that("GetInventory", {
 
 test_that("GetOrderById", {
   # tests for GetOrderById
+  # base path: http://petstore.swagger.io/v2
   # Find purchase order by ID
   # For valid response try integer IDs with value &lt;&#x3D; 5 or &gt; 10. Other values will generated exceptions
-  # @param order.id ID of pet that needs to be fetched
-  # @param [Hash] opts the optional parameters
+  # @param order.id integer ID of pet that needs to be fetched
   # @return [Order]
 
   # uncomment below to test the operation
@@ -42,9 +42,9 @@ test_that("GetOrderById", {
 
 test_that("PlaceOrder", {
   # tests for PlaceOrder
+  # base path: http://petstore.swagger.io/v2
   # Place an order for a pet
-  # @param body order placed for purchasing the pet
-  # @param [Hash] opts the optional parameters
+  # @param body Order order placed for purchasing the pet
   # @return [Order]
 
   # uncomment below to test the operation
diff --git a/samples/client/petstore/R/tests/testthat/test_user.R b/samples/client/petstore/R/tests/testthat/test_user.R
index 401196a90d7..9929623b42f 100644
--- a/samples/client/petstore/R/tests/testthat/test_user.R
+++ b/samples/client/petstore/R/tests/testthat/test_user.R
@@ -19,18 +19,18 @@ test_that("username", {
   #expect_equal(model.instance$`username`, "EXPECTED_RESULT")
 })
 
-test_that("first_name", {
-  # tests for the property `first_name` (character)
+test_that("firstName", {
+  # tests for the property `firstName` (character)
 
   # uncomment below to test the property 
-  #expect_equal(model.instance$`first_name`, "EXPECTED_RESULT")
+  #expect_equal(model.instance$`firstName`, "EXPECTED_RESULT")
 })
 
-test_that("last_name", {
-  # tests for the property `last_name` (character)
+test_that("lastName", {
+  # tests for the property `lastName` (character)
 
   # uncomment below to test the property 
-  #expect_equal(model.instance$`last_name`, "EXPECTED_RESULT")
+  #expect_equal(model.instance$`lastName`, "EXPECTED_RESULT")
 })
 
 test_that("email", {
@@ -54,11 +54,11 @@ test_that("phone", {
   #expect_equal(model.instance$`phone`, "EXPECTED_RESULT")
 })
 
-test_that("user_status", {
-  # tests for the property `user_status` (integer)
+test_that("userStatus", {
+  # tests for the property `userStatus` (integer)
   # User Status
 
   # uncomment below to test the property 
-  #expect_equal(model.instance$`user_status`, "EXPECTED_RESULT")
+  #expect_equal(model.instance$`userStatus`, "EXPECTED_RESULT")
 })
 
diff --git a/samples/client/petstore/R/tests/testthat/test_user_api.R b/samples/client/petstore/R/tests/testthat/test_user_api.R
index 283c7c7e964..8b8c3ba3847 100644
--- a/samples/client/petstore/R/tests/testthat/test_user_api.R
+++ b/samples/client/petstore/R/tests/testthat/test_user_api.R
@@ -7,10 +7,10 @@ api.instance <- UserApi$new()
 
 test_that("CreateUser", {
   # tests for CreateUser
+  # base path: http://petstore.swagger.io/v2
   # Create user
   # This can only be done by the logged in user.
-  # @param body Created user object
-  # @param [Hash] opts the optional parameters
+  # @param body User Created user object
   # @return [Void]
 
   # uncomment below to test the operation
@@ -19,9 +19,9 @@ test_that("CreateUser", {
 
 test_that("CreateUsersWithArrayInput", {
   # tests for CreateUsersWithArrayInput
+  # base path: http://petstore.swagger.io/v2
   # Creates list of users with given input array
-  # @param body List of user object
-  # @param [Hash] opts the optional parameters
+  # @param body array[User] List of user object
   # @return [Void]
 
   # uncomment below to test the operation
@@ -30,9 +30,9 @@ test_that("CreateUsersWithArrayInput", {
 
 test_that("CreateUsersWithListInput", {
   # tests for CreateUsersWithListInput
+  # base path: http://petstore.swagger.io/v2
   # Creates list of users with given input array
-  # @param body List of user object
-  # @param [Hash] opts the optional parameters
+  # @param body array[User] List of user object
   # @return [Void]
 
   # uncomment below to test the operation
@@ -41,10 +41,10 @@ test_that("CreateUsersWithListInput", {
 
 test_that("DeleteUser", {
   # tests for DeleteUser
+  # base path: http://petstore.swagger.io/v2
   # Delete user
   # This can only be done by the logged in user.
-  # @param username The name that needs to be deleted
-  # @param [Hash] opts the optional parameters
+  # @param username character The name that needs to be deleted
   # @return [Void]
 
   # uncomment below to test the operation
@@ -53,9 +53,9 @@ test_that("DeleteUser", {
 
 test_that("GetUserByName", {
   # tests for GetUserByName
+  # base path: http://petstore.swagger.io/v2
   # Get user by user name
-  # @param username The name that needs to be fetched. Use user1 for testing.
-  # @param [Hash] opts the optional parameters
+  # @param username character The name that needs to be fetched. Use user1 for testing.
   # @return [User]
 
   # uncomment below to test the operation
@@ -64,10 +64,10 @@ test_that("GetUserByName", {
 
 test_that("LoginUser", {
   # tests for LoginUser
+  # base path: http://petstore.swagger.io/v2
   # Logs user into the system
-  # @param username The user name for login
-  # @param password The password for login in clear text
-  # @param [Hash] opts the optional parameters
+  # @param username character The user name for login
+  # @param password character The password for login in clear text
   # @return [character]
 
   # uncomment below to test the operation
@@ -76,8 +76,8 @@ test_that("LoginUser", {
 
 test_that("LogoutUser", {
   # tests for LogoutUser
+  # base path: http://petstore.swagger.io/v2
   # Logs out current logged in user session
-  # @param [Hash] opts the optional parameters
   # @return [Void]
 
   # uncomment below to test the operation
@@ -86,11 +86,11 @@ test_that("LogoutUser", {
 
 test_that("UpdateUser", {
   # tests for UpdateUser
+  # base path: http://petstore.swagger.io/v2
   # Updated user
   # This can only be done by the logged in user.
-  # @param username name that need to be deleted
-  # @param body Updated user object
-  # @param [Hash] opts the optional parameters
+  # @param username character name that need to be deleted
+  # @param body User Updated user object
   # @return [Void]
 
   # uncomment below to test the operation
diff --git a/samples/client/petstore/R/testthat.R b/samples/client/petstore/R/testthat.R
deleted file mode 100644
index d67bd9cf238..00000000000
--- a/samples/client/petstore/R/testthat.R
+++ /dev/null
@@ -1,4 +0,0 @@
-library(testthat)
-library(petstore)
-
-test_check("petstore")