fix: Actually test that the response is sealed

Before, this was testing the response object passed to
callbacks which is not currently the same object than
the one processed in the lib.

Author: eFrane

test/api/Api-requests.spec.js

@@ -51,21 +51,10 @@ test('executes error callbacks', async () => {
 })
 
 test('response is sealed', async () => {
-  const newProp = (response) => {
+  await expect(api.get('/').then(response => {
     response.new_prop = 'test'
-  }
-
-  api.addSuccessCallback(newProp)
-  await expect(api.get('/')).rejects.toThrowErrorMatchingSnapshot()
-
-  const changeProp = (response) => {
     response.ok = false
-  }
-
-  api.resetSuccessCallbacks()
-  api.addSuccessCallback(changeProp)
-
-  await expect(api.get('/')).rejects.toThrowErrorMatchingSnapshot()
+  })).rejects.toThrowErrorMatchingSnapshot()
 })
 
 test('verb methods pass to _doRequest', () => {

test/api/__snapshots__/Api-requests.spec.js.snap

@@ -1,5 +1,3 @@
 // Jest Snapshot v1, https://goo.gl/fbAQLP
 
 exports[`response is sealed 1`] = `"Cannot define property new_prop, object is not extensible"`;
-
-exports[`response is sealed 2`] = `"Cannot set property ok of #<Response> which has only a getter"`;