Make existing tests test something, return correct errors.

app/controllers/projects_controller.rb

@@ -164,12 +164,21 @@ class ProjectsController < ApplicationController
 
   def upload_image
     uploader = FileUploader.new('uploads', upload_path, accepted_images)
-    alt = params['markdown_img'].original_filename
-    uploader.store!(params['markdown_img'])
+    image = params['markdown_img']
+
+    if image && accepted_images.map{ |format| image.content_type.include? format }.any?
+      alt = image.original_filename
+      uploader.store!(image)
       link = { 'alt' => File.basename(alt, '.*'),
                'url' => File.join(root_url, uploader.url) }
+    end
+
     respond_to do |format|
+      if link
         format.json { render json: { link: link } }
+      else
+        format.json { render json: "Invalid file.", status: :unprocessable_entity }
+      end
     end
   end
 

app/uploaders/file_uploader.rb

@@ -25,7 +25,7 @@ class FileUploader < CarrierWave::Uploader::Base
   end
 
   def store!(file)
-    file.original_filename = self.class.generate_filename(file)
+    @filename = self.class.generate_filename(file)
     super
   end
 

spec/controllers/projects_controller_spec.rb

@@ -11,33 +11,34 @@ describe ProjectsController do
   describe "POST #upload_image" do
     before do
       sign_in(user)
+      project.team << [user, :developer]
     end
 
     context "without params['markdown_img']" do
       it "returns an error" do
-        post :upload_image, id: project.to_param
-        expect(response.status).to eq(404)
+        post :upload_image, id: project.to_param, format: :json
+        expect(response.status).to eq(422)
       end
     end
 
     context "with invalid file" do
       before do
-        post :upload_image, id: project.to_param, markdown_img: @img
+        post :upload_image, id: project.to_param, markdown_img: txt, format: :json
       end
 
       it "returns an error" do
-        expect(response.status).to eq(404)
+        expect(response.status).to eq(422)
       end
     end
 
     context "with valid file" do
       before do
-        post :upload_image, id: project.to_param, markdown_img: @img
+        post :upload_image, id: project.to_param, markdown_img: jpg, format: :json
       end
 
       it "returns a content with original filename and new link." do
-        link = { alt: 'rails_sample', link: '' }.to_json
-        expect(response.body).to have_content link
+        expect(response.body).to match "\"alt\":\"rails_sample\""
+        expect(response.body).to match "\"url\":\"http://test.host/uploads/#{project.path_with_namespace}"
       end
     end
   end