fix: show ims error response body message (#165)

Author: moritzraho

src/ims.js

@@ -87,11 +87,11 @@ async function _sendRequest (method, url, token, data) {
 
   const retryOptions = { maxRetries: 3, initialDelayInMillis: 500 }
 
-  const validateResponse = (res) => {
+  const validateResponse = async (res) => {
     if (res.status === 200) {
       return res
     }
-    throw (new Error(`${res.status} (${res.statusText})`))
+    throw (new Error(`${res.status} (${res.statusText}): ${await res.text()}`))
   }
 
   const handleTextResponse = (text) => {

test/ims.test.js

@@ -696,7 +696,8 @@ test('Ims.post throw error on unsuccessfully request', async () => {
   const ims = new Ims()
   const serverResponse = {
     status: 400,
-    statusText: 'Bad Request'
+    statusText: 'Bad Request',
+    text: () => Promise.resolve('some error message')
   }
   mockExponentialBackoff.mockImplementationOnce(() => Promise.resolve(serverResponse))
   const result = ims.post('api', 'token', 'parameters')