diff --git a/modules/openapi-generator/src/main/resources/r/modelAnyOf.mustache b/modules/openapi-generator/src/main/resources/r/modelAnyOf.mustache
index 5b0e047fbaf..d27c5cedbb5 100644
--- a/modules/openapi-generator/src/main/resources/r/modelAnyOf.mustache
+++ b/modules/openapi-generator/src/main/resources/r/modelAnyOf.mustache
@@ -71,13 +71,27 @@
     #'
     #' @return JSON string reprenation of the {{{classname}}}.
     #' @export
-    toJSON = function() {
+    toJSONString = function() {
       if (!is.null(self$actual_instance)) {
         self$actual_instance$toJSONString()
       } else {
         NULL
       }
     },
+    #' Serialize {{{classname}}} to JSON.
+    #'
+    #' @description
+    #' Serialize {{{classname}}} to JSON.
+    #'
+    #' @return JSON reprenation of the {{{classname}}}.
+    #' @export
+    toJSON = function() {
+      if (!is.null(self$actual_instance)) {
+        self$actual_instance$toJSON()
+      } else {
+        NULL
+      }
+    },
     #' Validate the input JSON with respect to {{{classname}}}.
     #'
     #' @description
diff --git a/modules/openapi-generator/src/main/resources/r/modelGeneric.mustache b/modules/openapi-generator/src/main/resources/r/modelGeneric.mustache
index 539025096d9..d55150d0f73 100644
--- a/modules/openapi-generator/src/main/resources/r/modelGeneric.mustache
+++ b/modules/openapi-generator/src/main/resources/r/modelGeneric.mustache
@@ -266,7 +266,7 @@
       {{/vars}}
       )
       jsoncontent <- paste(jsoncontent, collapse = ",")
-      jsonlite::minify(paste('{', jsoncontent, '}', sep = ""))
+      as.character(jsonlite::minify(paste('{', jsoncontent, '}', sep = "")))
     },
     #' Deserialize JSON string into an instance of {{{classname}}}
     #'
diff --git a/modules/openapi-generator/src/main/resources/r/modelOneOf.mustache b/modules/openapi-generator/src/main/resources/r/modelOneOf.mustache
index 2e67fd5e68b..d53f32f59fa 100644
--- a/modules/openapi-generator/src/main/resources/r/modelOneOf.mustache
+++ b/modules/openapi-generator/src/main/resources/r/modelOneOf.mustache
@@ -86,13 +86,27 @@
     #'
     #' @return JSON string reprenation of the {{{classname}}}.
     #' @export
-    toJSON = function() {
+    toJSONString = function() {
       if (!is.null(self$actual_instance)) {
         self$actual_instance$toJSONString()
       } else {
         NULL
       }
     },
+    #' Serialize {{{classname}}} to JSON.
+    #'
+    #' @description
+    #' Serialize {{{classname}}} to JSON.
+    #'
+    #' @return JSON reprenation of the {{{classname}}}.
+    #' @export
+    toJSON = function() {
+      if (!is.null(self$actual_instance)) {
+        self$actual_instance$toJSON()
+      } else {
+        NULL
+      }
+    },
     #' Validate the input JSON with respect to {{{classname}}}.
     #'
     #' @description
diff --git a/modules/openapi-generator/src/test/resources/3_0/r/petstore.yaml b/modules/openapi-generator/src/test/resources/3_0/r/petstore.yaml
index 22a80bb3148..b6c2731285d 100644
--- a/modules/openapi-generator/src/test/resources/3_0/r/petstore.yaml
+++ b/modules/openapi-generator/src/test/resources/3_0/r/petstore.yaml
@@ -863,3 +863,10 @@ components:
       required:
         - className
         - size
+    NestedOneOf:
+      type: object
+      properties:
+        size:
+          type: integer
+        nested_pig:
+          $ref: '#/components/schemas/Pig'
diff --git a/samples/client/petstore/R/.openapi-generator/FILES b/samples/client/petstore/R/.openapi-generator/FILES
index 61126f669d8..3046316ea30 100644
--- a/samples/client/petstore/R/.openapi-generator/FILES
+++ b/samples/client/petstore/R/.openapi-generator/FILES
@@ -18,6 +18,7 @@ R/dog.R
 R/dog_all_of.R
 R/fake_api.R
 R/model_api_response.R
+R/nested_one_of.R
 R/order.R
 R/pet.R
 R/pet_api.R
@@ -41,6 +42,7 @@ docs/Dog.md
 docs/DogAllOf.md
 docs/FakeApi.md
 docs/ModelApiResponse.md
+docs/NestedOneOf.md
 docs/Order.md
 docs/Pet.md
 docs/PetApi.md
diff --git a/samples/client/petstore/R/NAMESPACE b/samples/client/petstore/R/NAMESPACE
index 2f72275d495..d8fc867efa7 100644
--- a/samples/client/petstore/R/NAMESPACE
+++ b/samples/client/petstore/R/NAMESPACE
@@ -23,6 +23,7 @@ export(DanishPig)
 export(Dog)
 export(DogAllOf)
 export(ModelApiResponse)
+export(NestedOneOf)
 export(Order)
 export(Pet)
 export(Pig)
diff --git a/samples/client/petstore/R/R/allof_tag_api_response.R b/samples/client/petstore/R/R/allof_tag_api_response.R
index 49d7c3872cb..1b7a67a078e 100644
--- a/samples/client/petstore/R/R/allof_tag_api_response.R
+++ b/samples/client/petstore/R/R/allof_tag_api_response.R
@@ -167,7 +167,7 @@ AllofTagApiResponse <- R6::R6Class(
         )}
       )
       jsoncontent <- paste(jsoncontent, collapse = ",")
-      jsonlite::minify(paste('{', jsoncontent, '}', sep = ""))
+      as.character(jsonlite::minify(paste('{', jsoncontent, '}', sep = "")))
     },
     #' Deserialize JSON string into an instance of AllofTagApiResponse
     #'
diff --git a/samples/client/petstore/R/R/animal.R b/samples/client/petstore/R/R/animal.R
index 860f5284901..043e6f50431 100644
--- a/samples/client/petstore/R/R/animal.R
+++ b/samples/client/petstore/R/R/animal.R
@@ -104,7 +104,7 @@ Animal <- R6::R6Class(
         )}
       )
       jsoncontent <- paste(jsoncontent, collapse = ",")
-      jsonlite::minify(paste('{', jsoncontent, '}', sep = ""))
+      as.character(jsonlite::minify(paste('{', jsoncontent, '}', sep = "")))
     },
     #' Deserialize JSON string into an instance of Animal
     #'
diff --git a/samples/client/petstore/R/R/any_of_pig.R b/samples/client/petstore/R/R/any_of_pig.R
index 23c24102381..73b8e89c6f9 100644
--- a/samples/client/petstore/R/R/any_of_pig.R
+++ b/samples/client/petstore/R/R/any_of_pig.R
@@ -94,13 +94,27 @@ AnyOfPig <- R6::R6Class(
     #'
     #' @return JSON string reprenation of the AnyOfPig.
     #' @export
-    toJSON = function() {
+    toJSONString = function() {
       if (!is.null(self$actual_instance)) {
         self$actual_instance$toJSONString()
       } else {
         NULL
       }
     },
+    #' Serialize AnyOfPig to JSON.
+    #'
+    #' @description
+    #' Serialize AnyOfPig to JSON.
+    #'
+    #' @return JSON reprenation of the AnyOfPig.
+    #' @export
+    toJSON = function() {
+      if (!is.null(self$actual_instance)) {
+        self$actual_instance$toJSON()
+      } else {
+        NULL
+      }
+    },
     #' Validate the input JSON with respect to AnyOfPig.
     #'
     #' @description
diff --git a/samples/client/petstore/R/R/basque_pig.R b/samples/client/petstore/R/R/basque_pig.R
index 04d568cd9c0..ad3a3d8b84d 100644
--- a/samples/client/petstore/R/R/basque_pig.R
+++ b/samples/client/petstore/R/R/basque_pig.R
@@ -104,7 +104,7 @@ BasquePig <- R6::R6Class(
         )}
       )
       jsoncontent <- paste(jsoncontent, collapse = ",")
-      jsonlite::minify(paste('{', jsoncontent, '}', sep = ""))
+      as.character(jsonlite::minify(paste('{', jsoncontent, '}', sep = "")))
     },
     #' Deserialize JSON string into an instance of BasquePig
     #'
diff --git a/samples/client/petstore/R/R/cat.R b/samples/client/petstore/R/R/cat.R
index 08d4ff1b9ab..9e70f50a0c1 100644
--- a/samples/client/petstore/R/R/cat.R
+++ b/samples/client/petstore/R/R/cat.R
@@ -126,7 +126,7 @@ Cat <- R6::R6Class(
         )}
       )
       jsoncontent <- paste(jsoncontent, collapse = ",")
-      jsonlite::minify(paste('{', jsoncontent, '}', sep = ""))
+      as.character(jsonlite::minify(paste('{', jsoncontent, '}', sep = "")))
     },
     #' Deserialize JSON string into an instance of Cat
     #'
diff --git a/samples/client/petstore/R/R/cat_all_of.R b/samples/client/petstore/R/R/cat_all_of.R
index 1dabfdff72b..cbdad46b9dd 100644
--- a/samples/client/petstore/R/R/cat_all_of.R
+++ b/samples/client/petstore/R/R/cat_all_of.R
@@ -83,7 +83,7 @@ CatAllOf <- R6::R6Class(
         )}
       )
       jsoncontent <- paste(jsoncontent, collapse = ",")
-      jsonlite::minify(paste('{', jsoncontent, '}', sep = ""))
+      as.character(jsonlite::minify(paste('{', jsoncontent, '}', sep = "")))
     },
     #' Deserialize JSON string into an instance of CatAllOf
     #'
diff --git a/samples/client/petstore/R/R/category.R b/samples/client/petstore/R/R/category.R
index f0b33419e4a..986a5065142 100644
--- a/samples/client/petstore/R/R/category.R
+++ b/samples/client/petstore/R/R/category.R
@@ -104,7 +104,7 @@ Category <- R6::R6Class(
         )}
       )
       jsoncontent <- paste(jsoncontent, collapse = ",")
-      jsonlite::minify(paste('{', jsoncontent, '}', sep = ""))
+      as.character(jsonlite::minify(paste('{', jsoncontent, '}', sep = "")))
     },
     #' Deserialize JSON string into an instance of Category
     #'
diff --git a/samples/client/petstore/R/R/danish_pig.R b/samples/client/petstore/R/R/danish_pig.R
index 716479eb2a3..00caeda1ef9 100644
--- a/samples/client/petstore/R/R/danish_pig.R
+++ b/samples/client/petstore/R/R/danish_pig.R
@@ -104,7 +104,7 @@ DanishPig <- R6::R6Class(
         )}
       )
       jsoncontent <- paste(jsoncontent, collapse = ",")
-      jsonlite::minify(paste('{', jsoncontent, '}', sep = ""))
+      as.character(jsonlite::minify(paste('{', jsoncontent, '}', sep = "")))
     },
     #' Deserialize JSON string into an instance of DanishPig
     #'
diff --git a/samples/client/petstore/R/R/dog.R b/samples/client/petstore/R/R/dog.R
index 5ce00cd5593..596e3e74a14 100644
--- a/samples/client/petstore/R/R/dog.R
+++ b/samples/client/petstore/R/R/dog.R
@@ -126,7 +126,7 @@ Dog <- R6::R6Class(
         )}
       )
       jsoncontent <- paste(jsoncontent, collapse = ",")
-      jsonlite::minify(paste('{', jsoncontent, '}', sep = ""))
+      as.character(jsonlite::minify(paste('{', jsoncontent, '}', sep = "")))
     },
     #' Deserialize JSON string into an instance of Dog
     #'
diff --git a/samples/client/petstore/R/R/dog_all_of.R b/samples/client/petstore/R/R/dog_all_of.R
index e34354cde44..b7e1b355f49 100644
--- a/samples/client/petstore/R/R/dog_all_of.R
+++ b/samples/client/petstore/R/R/dog_all_of.R
@@ -83,7 +83,7 @@ DogAllOf <- R6::R6Class(
         )}
       )
       jsoncontent <- paste(jsoncontent, collapse = ",")
-      jsonlite::minify(paste('{', jsoncontent, '}', sep = ""))
+      as.character(jsonlite::minify(paste('{', jsoncontent, '}', sep = "")))
     },
     #' Deserialize JSON string into an instance of DogAllOf
     #'
diff --git a/samples/client/petstore/R/R/model_api_response.R b/samples/client/petstore/R/R/model_api_response.R
index 88ec1289afe..28477200f62 100644
--- a/samples/client/petstore/R/R/model_api_response.R
+++ b/samples/client/petstore/R/R/model_api_response.R
@@ -125,7 +125,7 @@ ModelApiResponse <- R6::R6Class(
         )}
       )
       jsoncontent <- paste(jsoncontent, collapse = ",")
-      jsonlite::minify(paste('{', jsoncontent, '}', sep = ""))
+      as.character(jsonlite::minify(paste('{', jsoncontent, '}', sep = "")))
     },
     #' Deserialize JSON string into an instance of ModelApiResponse
     #'
diff --git a/samples/client/petstore/R/R/nested_one_of.R b/samples/client/petstore/R/R/nested_one_of.R
new file mode 100644
index 00000000000..f40db2629ac
--- /dev/null
+++ b/samples/client/petstore/R/R/nested_one_of.R
@@ -0,0 +1,147 @@
+#' OpenAPI Petstore
+#'
+#' This is a sample server Petstore server. For this sample, you can use the api key `special-key` to test the authorization filters.
+#'
+#' The version of the OpenAPI document: 1.0.0
+#' Generated by: https://openapi-generator.tech
+#'
+
+#' @docType class
+#' @title NestedOneOf
+#' @description NestedOneOf Class
+#' @format An \code{R6Class} generator object
+#' @field size  integer [optional]
+#' @field nested_pig  \link{Pig} [optional]
+#' @importFrom R6 R6Class
+#' @importFrom jsonlite fromJSON toJSON
+#' @export
+NestedOneOf <- R6::R6Class(
+  'NestedOneOf',
+  public = list(
+    `size` = NULL,
+    `nested_pig` = NULL,
+    #' Initialize a new NestedOneOf class.
+    #'
+    #' @description
+    #' Initialize a new NestedOneOf class.
+    #'
+    #' @param size size
+    #' @param nested_pig nested_pig
+    #' @param ... Other optional arguments.
+    #' @export
+    initialize = function(
+        `size`=NULL, `nested_pig`=NULL, ...
+    ) {
+      if (!is.null(`size`)) {
+        stopifnot(is.numeric(`size`), length(`size`) == 1)
+        self$`size` <- `size`
+      }
+      if (!is.null(`nested_pig`)) {
+        stopifnot(R6::is.R6(`nested_pig`))
+        self$`nested_pig` <- `nested_pig`
+      }
+    },
+    #' To JSON string
+    #'
+    #' @description
+    #' To JSON String
+    #'
+    #' @return NestedOneOf in JSON format
+    #' @export
+    toJSON = function() {
+      NestedOneOfObject <- list()
+      if (!is.null(self$`size`)) {
+        NestedOneOfObject[['size']] <-
+          self$`size`
+      }
+      if (!is.null(self$`nested_pig`)) {
+        NestedOneOfObject[['nested_pig']] <-
+          self$`nested_pig`$toJSON()
+      }
+
+      NestedOneOfObject
+    },
+    #' Deserialize JSON string into an instance of NestedOneOf
+    #'
+    #' @description
+    #' Deserialize JSON string into an instance of NestedOneOf
+    #'
+    #' @param input_json the JSON input
+    #' @return the instance of NestedOneOf
+    #' @export
+    fromJSON = function(input_json) {
+      this_object <- jsonlite::fromJSON(input_json)
+      if (!is.null(this_object$`size`)) {
+        self$`size` <- this_object$`size`
+      }
+      if (!is.null(this_object$`nested_pig`)) {
+        nested_pig_object <- Pig$new()
+        nested_pig_object$fromJSON(jsonlite::toJSON(this_object$nested_pig, auto_unbox = TRUE, digits = NA))
+        self$`nested_pig` <- nested_pig_object
+      }
+      self
+    },
+    #' To JSON string
+    #'
+    #' @description
+    #' To JSON String
+    #'
+    #' @return NestedOneOf in JSON format
+    #' @export
+    toJSONString = function() {
+      jsoncontent <- c(
+        if (!is.null(self$`size`)) {
+        sprintf(
+        '"size":
+          %d
+                ',
+        self$`size`
+        )},
+        if (!is.null(self$`nested_pig`)) {
+        sprintf(
+        '"nested_pig":
+        %s
+        ',
+        jsonlite::toJSON(self$`nested_pig`$toJSON(), auto_unbox=TRUE, digits = NA)
+        )}
+      )
+      jsoncontent <- paste(jsoncontent, collapse = ",")
+      as.character(jsonlite::minify(paste('{', jsoncontent, '}', sep = "")))
+    },
+    #' Deserialize JSON string into an instance of NestedOneOf
+    #'
+    #' @description
+    #' Deserialize JSON string into an instance of NestedOneOf
+    #'
+    #' @param input_json the JSON input
+    #' @return the instance of NestedOneOf
+    #' @export
+    fromJSONString = function(input_json) {
+      this_object <- jsonlite::fromJSON(input_json)
+      self$`size` <- this_object$`size`
+      self$`nested_pig` <- Pig$new()$fromJSON(jsonlite::toJSON(this_object$nested_pig, auto_unbox = TRUE, digits = NA))
+      self
+    },
+    #' Validate JSON input with respect to NestedOneOf
+    #'
+    #' @description
+    #' Validate JSON input with respect to NestedOneOf and throw an exception if invalid
+    #'
+    #' @param input the JSON input
+    #' @export
+    validateJSON = function(input) {
+      input_json <- jsonlite::fromJSON(input)
+    },
+    #' To string (JSON format)
+    #'
+    #' @description
+    #' To string (JSON format)
+    #'
+    #' @return String representation of NestedOneOf
+    #' @export
+    toString = function() {
+      self$toJSONString()
+    }
+  )
+)
+
diff --git a/samples/client/petstore/R/R/order.R b/samples/client/petstore/R/R/order.R
index e676946ba2b..f7ce4aa1cd2 100644
--- a/samples/client/petstore/R/R/order.R
+++ b/samples/client/petstore/R/R/order.R
@@ -188,7 +188,7 @@ Order <- R6::R6Class(
         )}
       )
       jsoncontent <- paste(jsoncontent, collapse = ",")
-      jsonlite::minify(paste('{', jsoncontent, '}', sep = ""))
+      as.character(jsonlite::minify(paste('{', jsoncontent, '}', sep = "")))
     },
     #' Deserialize JSON string into an instance of Order
     #'
diff --git a/samples/client/petstore/R/R/pet.R b/samples/client/petstore/R/R/pet.R
index fce32f92e52..f3345adc046 100644
--- a/samples/client/petstore/R/R/pet.R
+++ b/samples/client/petstore/R/R/pet.R
@@ -192,7 +192,7 @@ Pet <- R6::R6Class(
         )}
       )
       jsoncontent <- paste(jsoncontent, collapse = ",")
-      jsonlite::minify(paste('{', jsoncontent, '}', sep = ""))
+      as.character(jsonlite::minify(paste('{', jsoncontent, '}', sep = "")))
     },
     #' Deserialize JSON string into an instance of Pet
     #'
diff --git a/samples/client/petstore/R/R/pig.R b/samples/client/petstore/R/R/pig.R
index 4887ec3d26c..565df078209 100644
--- a/samples/client/petstore/R/R/pig.R
+++ b/samples/client/petstore/R/R/pig.R
@@ -110,13 +110,27 @@ Pig <- R6::R6Class(
     #'
     #' @return JSON string reprenation of the Pig.
     #' @export
-    toJSON = function() {
+    toJSONString = function() {
       if (!is.null(self$actual_instance)) {
         self$actual_instance$toJSONString()
       } else {
         NULL
       }
     },
+    #' Serialize Pig to JSON.
+    #'
+    #' @description
+    #' Serialize Pig to JSON.
+    #'
+    #' @return JSON reprenation of the Pig.
+    #' @export
+    toJSON = function() {
+      if (!is.null(self$actual_instance)) {
+        self$actual_instance$toJSON()
+      } else {
+        NULL
+      }
+    },
     #' Validate the input JSON with respect to Pig.
     #'
     #' @description
diff --git a/samples/client/petstore/R/R/special.R b/samples/client/petstore/R/R/special.R
index 2f14118b02f..7d34c26a9af 100644
--- a/samples/client/petstore/R/R/special.R
+++ b/samples/client/petstore/R/R/special.R
@@ -146,7 +146,7 @@ Special <- R6::R6Class(
         )}
       )
       jsoncontent <- paste(jsoncontent, collapse = ",")
-      jsonlite::minify(paste('{', jsoncontent, '}', sep = ""))
+      as.character(jsonlite::minify(paste('{', jsoncontent, '}', sep = "")))
     },
     #' Deserialize JSON string into an instance of Special
     #'
diff --git a/samples/client/petstore/R/R/tag.R b/samples/client/petstore/R/R/tag.R
index 6b0d17a2d0c..e58c9899a10 100644
--- a/samples/client/petstore/R/R/tag.R
+++ b/samples/client/petstore/R/R/tag.R
@@ -104,7 +104,7 @@ Tag <- R6::R6Class(
         )}
       )
       jsoncontent <- paste(jsoncontent, collapse = ",")
-      jsonlite::minify(paste('{', jsoncontent, '}', sep = ""))
+      as.character(jsonlite::minify(paste('{', jsoncontent, '}', sep = "")))
     },
     #' Deserialize JSON string into an instance of Tag
     #'
diff --git a/samples/client/petstore/R/R/update_pet_request.R b/samples/client/petstore/R/R/update_pet_request.R
index 7a7f6026479..2756c970f54 100644
--- a/samples/client/petstore/R/R/update_pet_request.R
+++ b/samples/client/petstore/R/R/update_pet_request.R
@@ -105,7 +105,7 @@ UpdatePetRequest <- R6::R6Class(
         )}
       )
       jsoncontent <- paste(jsoncontent, collapse = ",")
-      jsonlite::minify(paste('{', jsoncontent, '}', sep = ""))
+      as.character(jsonlite::minify(paste('{', jsoncontent, '}', sep = "")))
     },
     #' Deserialize JSON string into an instance of UpdatePetRequest
     #'
diff --git a/samples/client/petstore/R/R/user.R b/samples/client/petstore/R/R/user.R
index 2016a2dce29..3379f7cfa75 100644
--- a/samples/client/petstore/R/R/user.R
+++ b/samples/client/petstore/R/R/user.R
@@ -230,7 +230,7 @@ User <- R6::R6Class(
         )}
       )
       jsoncontent <- paste(jsoncontent, collapse = ",")
-      jsonlite::minify(paste('{', jsoncontent, '}', sep = ""))
+      as.character(jsonlite::minify(paste('{', jsoncontent, '}', sep = "")))
     },
     #' Deserialize JSON string into an instance of User
     #'
diff --git a/samples/client/petstore/R/README.md b/samples/client/petstore/R/README.md
index eb829f1e420..79c2d3f042d 100644
--- a/samples/client/petstore/R/README.md
+++ b/samples/client/petstore/R/README.md
@@ -97,6 +97,7 @@ Class | Method | HTTP request | Description
  - [Dog](docs/Dog.md)
  - [DogAllOf](docs/DogAllOf.md)
  - [ModelApiResponse](docs/ModelApiResponse.md)
+ - [NestedOneOf](docs/NestedOneOf.md)
  - [Order](docs/Order.md)
  - [Pet](docs/Pet.md)
  - [Pig](docs/Pig.md)
diff --git a/samples/client/petstore/R/docs/NestedOneOf.md b/samples/client/petstore/R/docs/NestedOneOf.md
new file mode 100644
index 00000000000..ecc2ed89144
--- /dev/null
+++ b/samples/client/petstore/R/docs/NestedOneOf.md
@@ -0,0 +1,10 @@
+# petstore::NestedOneOf
+
+
+## Properties
+Name | Type | Description | Notes
+------------ | ------------- | ------------- | -------------
+**size** | **integer** |  | [optional] 
+**nested_pig** | [**Pig**](Pig.md) |  | [optional] 
+
+
diff --git a/samples/client/petstore/R/test_petstore.R b/samples/client/petstore/R/test_petstore.R
index e75bf247140..ff95be9432d 100644
--- a/samples/client/petstore/R/test_petstore.R
+++ b/samples/client/petstore/R/test_petstore.R
@@ -67,8 +67,8 @@ toString(pet$toString())
 ##Pet$my_static_method <- function(x) { x + 2}
 ##Pet$public_methods$my_static_method(1)
 #
-#  basque_pig_json <-
-#  '{"className2": "BasquePig", "color": "red"}'
+  basque_pig_json <-
+  '{"className2": "BasquePig", "color": "red"}'
 # 
 #  danish_pig_json <-
 #  '{"className2": "DanishPig", "size": 7}'
@@ -81,8 +81,8 @@ toString(pet$toString())
 #  ]'
 #
 #  print("==========") 
-#  pig <- Pig$new()
-#  basque_pig <- pig$fromJSON(basque_pig_json)
+  pig <- Pig$new()
+  basque_pig <- pig$fromJSON(basque_pig_json)
 #  #print(basque_pig$actual_instance$color)
 #  #expect_equal(basque_pig$actual_type, "BasquePig")
 #  pig$fromJSON(danish_pig_json)
@@ -93,3 +93,11 @@ toString(pet$toString())
 #  #dp <- d$validateJSON(danish_pig_json)
 #
 #
+
+# test nested oneOf
+nested_oneof <- NestedOneOf$new()
+nested_oneof$nested_pig <- pig
+nested_oneof$size <- 15
+
+cat(nested_oneof$toJSONString())
+
diff --git a/samples/client/petstore/R/tests/testthat/test_nested_one_of.R b/samples/client/petstore/R/tests/testthat/test_nested_one_of.R
new file mode 100644
index 00000000000..940a7fba2a6
--- /dev/null
+++ b/samples/client/petstore/R/tests/testthat/test_nested_one_of.R
@@ -0,0 +1,20 @@
+# Automatically generated by openapi-generator (https://openapi-generator.tech)
+# Please update as you see appropriate
+
+context("Test NestedOneOf")
+
+model_instance <- NestedOneOf$new()
+
+test_that("size", {
+  # tests for the property `size` (integer)
+
+  # uncomment below to test the property
+  #expect_equal(model.instance$`size`, "EXPECTED_RESULT")
+})
+
+test_that("nested_pig", {
+  # tests for the property `nested_pig` (Pig)
+
+  # uncomment below to test the property
+  #expect_equal(model.instance$`nested_pig`, "EXPECTED_RESULT")
+})
diff --git a/samples/client/petstore/R/tests/testthat/test_petstore.R b/samples/client/petstore/R/tests/testthat/test_petstore.R
index 8c5e1e39441..424fc5c291a 100644
--- a/samples/client/petstore/R/tests/testthat/test_petstore.R
+++ b/samples/client/petstore/R/tests/testthat/test_petstore.R
@@ -16,7 +16,7 @@ result <- pet_api$AddPet(pet)
 test_that("AddPet", {
   expect_equal(pet_id, 123321)
   #expect_equal(result, NULL)
-  #expect_equal(pet$toJSONString(), '{"id":123321,"category":{"id":450,"name":"test_cat"},"name":"name_test","photoUrls":["photo_test","second test"],"tags":[{"id":123,"name":"tag_test"},{"id":456,"name":"unknown"}],"status":"available"}')
+  expect_equal(pet$toJSONString(), '{"id":123321,"category":{"id":450,"name":"test_cat"},"name":"name_test","photoUrls":["photo_test","second test"],"tags":[{"id":123,"name":"tag_test"},{"id":456,"name":"unknown"}],"status":"available"}')
 })
 
 test_that("Test toJSON toJSONString fromJSON fromJSONString", {
@@ -154,7 +154,7 @@ test_that("Tests validateJSON", {
 })
 
 # test object with special item names: self, private, super
-test_that("Tests oneOf", {
+test_that("Tests special item names", {
   special_json <-
   '{"self": 123, "private": "red", "super": "something"}'
 
@@ -168,6 +168,7 @@ test_that("Tests oneOf", {
   expect_true(grepl('"private"', special$toJSONString()))
   expect_true(grepl('"self"', special$toJSONString()))
   expect_true(grepl('"super"', special$toJSONString()))
+  expect_equal('{"self":123,"private":"red","super":"something"}', special$toJSONString())
 
   # round trip test
   s1 <- Special$new()$fromJSONString(special_json)
@@ -206,13 +207,13 @@ test_that("Tests oneOf", {
   expect_equal(pig$actual_instance$className, "DanishPig")
 
   # test toJSON
-  expect_equal(danish_pig$toJSON(), original_danish_pig$toJSONString())
+  expect_equal(danish_pig$toJSONString(), original_danish_pig$toJSONString())
 
   basque_pig <- pig$fromJSON(basque_pig_json)
   expect_equal(basque_pig$actual_type, "BasquePig")
   expect_equal(basque_pig$actual_instance$color, "red")
   expect_equal(basque_pig$actual_instance$className, "BasquePig")
-  expect_equal(basque_pig$toJSON(), original_basque_pig$toJSONString())
+  expect_equal(basque_pig$toJSONString(), original_basque_pig$toJSONString())
 
   # test exception when no matche found
   expect_error(pig$fromJSON('{}'), 'No match found when deserializing the payload into Pig with oneOf schemas BasquePig, DanishPig. Details:  The JSON input ` \\{\\} ` is invalid for BasquePig: the required field `className` is missing\\., The JSON input ` \\{\\} ` is invalid for DanishPig: the required field `className` is missing\\.')
@@ -226,9 +227,16 @@ test_that("Tests oneOf", {
   expect_equal(pig2$actual_type, "BasquePig")
   expect_equal(pig2$actual_instance$color, "red")
   expect_equal(pig2$actual_instance$className, "BasquePig")
-  expect_equal(pig2$toJSON(), original_basque_pig$toJSONString())
+  expect_equal(pig2$toJSONString(), original_basque_pig$toJSONString())
   
   expect_error(Pig$new(instance = basque_pig), 'Failed to initialize Pig with oneOf schemas BasquePig, DanishPig. Provided class name:  Pig')
+
+  # test nested oneOf
+  nested_oneof <- NestedOneOf$new()
+  nested_oneof$nested_pig <- pig
+  nested_oneof$size <- 15
+  expect_equal(nested_oneof$toJSONString(), '{"size":15,"nested_pig":{"className":"BasquePig","color":"red"}}')
+   
 })
 
 test_that("Tests anyOf", {
@@ -260,13 +268,13 @@ test_that("Tests anyOf", {
   expect_equal(pig$actual_instance$className, "DanishPig")
 
   # test toJSON
-  expect_equal(danish_pig$toJSON(), original_danish_pig$toJSONString())
+  expect_equal(danish_pig$toJSONString(), original_danish_pig$toJSONString())
 
   basque_pig <- pig$fromJSON(basque_pig_json)
   expect_equal(basque_pig$actual_type, "BasquePig")
   expect_equal(basque_pig$actual_instance$color, "red")
   expect_equal(basque_pig$actual_instance$className, "BasquePig")
-  expect_equal(basque_pig$toJSON(), original_basque_pig$toJSONString())
+  expect_equal(basque_pig$toJSONString(), original_basque_pig$toJSONString())
 
   # test exception when no matche found
   expect_error(pig$fromJSON('{}'), 'No match found when deserializing the payload into AnyOfPig with anyOf schemas BasquePig, DanishPig. Details:  The JSON input ` \\{\\} ` is invalid for BasquePig: the required field `className` is missing\\., The JSON input ` \\{\\} ` is invalid for DanishPig: the required field `className` is missing\\.')