[misc] wordcount: restrict image to an allow list and add tests

test/acceptance/js/helpers/Client.js

@@ -189,6 +189,11 @@ module.exports = Client = {
   },
 
   wordcount(project_id, file, callback) {
+    const image = undefined
+    Client.wordcountWithImage(project_id, file, image, callback)
+  },
+
+  wordcountWithImage(project_id, file, image, callback) {
     if (callback == null) {
       callback = function(error, pdfPositions) {}
     }
@@ -196,6 +201,7 @@ module.exports = Client = {
       {
         url: `${this.host}/project/${project_id}/wordcount`,
         qs: {
+          image,
           file
         }
       },
@@ -203,6 +209,9 @@ module.exports = Client = {
         if (error != null) {
           return callback(error)
         }
+        if (response.statusCode !== 200) {
+          return callback(new Error(`statusCode=${response.statusCode}`))
+        }
         return callback(null, JSON.parse(body))
       }
     )