fix: Exporting to YAML preserves nil values in examples

Author: zorbash

lib/open_api_spex/open_api.ex

@@ -96,11 +96,15 @@ defmodule OpenApiSpex.OpenApi do
     defmodule YmlrEncoder do
       @moduledoc false
 
-      def encode(api_spec = %{}, _options) do
+      def encode(api_spec = %OpenApi{}, _options) do
         api_spec
         |> OpenApi.to_map()
         |> Ymlr.document()
       end
+
+      def encode(api_spec = %{}, _options) do
+        Ymlr.document(api_spec)
+      end
     end
 
     @yaml_encoder YmlrEncoder

test/support/tasks/openapi.json

@@ -1,4 +1,33 @@
 {
+  "components": {
+    "schemas": {
+      "Person": {
+        "example": {
+          "first_name": "John",
+          "last_name": "Doe",
+          "nickname": null
+        },
+        "properties": {
+          "first_name": {
+            "type": "string"
+          },
+          "last_name": {
+            "type": "string"
+          },
+          "nickname": {
+            "nullable": true,
+            "type": "string"
+          }
+        },
+        "required": [
+          "first_name",
+          "last_name",
+          "nickname"
+        ],
+        "type": "object"
+      }
+    }
+  },
   "info": {
     "title": "Test spec",
     "version": "1.0"

test/support/tasks/openapi.yaml

@@ -1,4 +1,24 @@
 ---
+components:
+  schemas:
+    Person:
+      example:
+        first_name: John
+        last_name: Doe
+        nickname:
+      properties:
+        first_name:
+          type: string
+        last_name:
+          type: string
+        nickname:
+          nullable: true
+          type: string
+      required:
+        - first_name
+        - last_name
+        - nickname
+      type: object
 info:
   title: Test spec
   version: '1.0'

test/support/tasks/spec_module.ex

@@ -18,7 +18,25 @@ defmodule OpenApiSpexTest.Tasks.SpecModule do
       },
       servers: [
         %Server{url: "http://localhost:4000"}
-      ]
+      ],
+      components: %{
+        schemas: %{
+          "Person" => %OpenApiSpex.Schema{
+            type: :object,
+            properties: %{
+              first_name: %OpenApiSpex.Schema{type: :string},
+              last_name: %OpenApiSpex.Schema{type: :string},
+              nickname: %OpenApiSpex.Schema{type: :string, nullable: true}
+            },
+            required: [:first_name, :last_name, :nickname],
+            example: %{
+              first_name: "John",
+              last_name: "Doe",
+              nickname: nil
+            }
+          }
+        }
+      }
     }
   end
 end