Remove controllers spec already tested elsewhere

spec/integration/api/api_sign_in_spec.rb

@@ -1,5 +1,7 @@
 describe 'API sign in' do
-  let(:user)  { FactoryGirl.create(:user) }
+  include AcceptanceHelpers
+
+  let(:user) { create :user }
 
   def do_create
     post api_sessions_path, format: :json, session: {
@@ -11,17 +13,20 @@ describe 'API sign in' do
   it 'signs the user in with valid credentials' do
     do_create
 
-    expect(response).to be_success
-    expect(JSON response.body).to include 'id'
+    expect(json).to eq({
+      id: user.id
+    })
   end
 
   [:email, :password].each do |attr|
-    it "rejects authentication with invalid credentials (#{attr})" do
-      allow(user).to receive(attr).and_return(user.send(attr) + '_INVALID')
-      do_create
+    context "with invalid #{attr}" do
+      it 'rejects authentication' do
+        allow(user).to receive(attr).and_return(user.send(attr) + '_INVALID')
+        do_create
 
-      expect(response).to be_not_found
-      expect(response.body).to be_empty
+        expect(response).to be_not_found
+        expect(response.body).to be_empty
+      end
     end
   end
 end