Stringify object values before serialization

src/execute/oas3/build-request.js

@@ -51,7 +51,7 @@ export default function (options, req) {
             Object.keys(requestBody).forEach((k) => {
               const val = requestBody[k]
               req.form[k] = {
-                value: val
+                value: typeof val === 'object' ? JSON.stringify(val) : val
               }
             })
           }

test/oas3/execute/main.js

@@ -169,6 +169,58 @@ describe('buildRequest - OpenAPI Specification 3.0', function () {
       })
     })
 
+    it('should stringify object values of form data bodies', function () {
+      // Given
+      const spec = {
+        openapi: '3.0.0',
+        servers: [
+          {
+            url: 'http://petstore.swagger.io/v2',
+            name: 'Petstore'
+          }
+        ],
+        paths: {
+          '/one': {
+            get: {
+              operationId: 'getOne',
+              requestBody: {
+                content: {
+                  'application/x-www-form-urlencoded': {
+                    schema: {
+                      type: 'object'
+                    }
+                  }
+                }
+              }
+            }
+          }
+        }
+      }
+
+      // when
+      const req = buildRequest({
+        spec,
+        operationId: 'getOne',
+        requestBody: {
+          a: 1,
+          b: {
+            c: 3,
+            d: 4
+          }
+        }
+      })
+
+      expect(req).toEqual({
+        method: 'GET',
+        url: 'http://petstore.swagger.io/v2/one',
+        credentials: 'same-origin',
+        headers: {
+          'Content-Type': 'application/x-www-form-urlencoded'
+        },
+        body: 'a=1&b=%7B%22c%22%3A3%2C%22d%22%3A4%7D'
+      })
+    })
+
     it('should build a request for the given operationId with a requestBody, and not be overriden by an invalid Swagger2 body parameter value', function () {
       // Given
       const spec = {