Spec for local auth check

app/controllers/session_controller.rb

@@ -2,7 +2,12 @@ require_dependency 'rate_limiter'
 require_dependency 'single_sign_on'
 
 class SessionController < ApplicationController
+  class LocalLoginNotAllowed < StandardError; end
+  rescue_from LocalLoginNotAllowed do
+    render nothing: true, status: 500
+  end
 
+  before_filter :check_local_login_allowed, only: %i(create forgot_password)
   skip_before_filter :redirect_to_login_if_required
   skip_before_filter :preload_json, :check_xhr, only: ['sso', 'sso_login', 'become', 'sso_provider', 'destroy']
 
@@ -176,12 +181,6 @@ class SessionController < ApplicationController
   end
 
   def create
-
-    unless allow_local_auth?
-      render nothing: true, status: 500
-      return
-    end
-
     RateLimiter.new(nil, "login-hr-#{request.remote_ip}", SiteSetting.max_logins_per_ip_per_hour, 1.hour).performed!
     RateLimiter.new(nil, "login-min-#{request.remote_ip}", SiteSetting.max_logins_per_ip_per_minute, 1.minute).performed!
 
@@ -234,11 +233,6 @@ class SessionController < ApplicationController
   def forgot_password
     params.require(:login)
 
-    unless allow_local_auth?
-      render nothing: true, status: 500
-      return
-    end
-
     RateLimiter.new(nil, "forgot-password-hr-#{request.remote_ip}", 6, 1.hour).performed!
     RateLimiter.new(nil, "forgot-password-min-#{request.remote_ip}", 3, 1.minute).performed!
 
@@ -281,12 +275,16 @@ class SessionController < ApplicationController
     end
   end
 
-  private
+  protected
 
-  def allow_local_auth?
-    !SiteSetting.enable_sso && SiteSetting.enable_local_logins
+  def check_local_login_allowed
+    if SiteSetting.enable_sso || !SiteSetting.enable_local_logins
+      raise LocalLoginNotAllowed, "SSO takes over local login or the local login is disallowed."
+    end
   end
 
+  private
+
   def login_not_approved_for?(user)
     SiteSetting.must_approve_users? && !user.approved? && !user.admin?
   end

spec/controllers/session_controller_spec.rb

@@ -1,6 +1,12 @@
 require 'rails_helper'
 
 describe SessionController do
+  shared_examples 'failed to continue local login' do
+    it 'should return the right response' do
+      expect(response).not_to be_success
+      expect(response.status.to_i).to eq 500
+    end
+  end
 
   describe 'become' do
     let!(:user) { Fabricate(:user) }
@@ -458,6 +464,22 @@ describe SessionController do
 
     let(:user) { Fabricate(:user) }
 
+    context 'local login is disabled' do
+      before do
+        SiteSetting.enable_local_logins = false
+        xhr :post, :create, login: user.username, password: 'myawesomepassword'
+      end
+      it_behaves_like "failed to continue local login"
+    end
+
+    context 'SSO is enabled' do
+      before do
+        SiteSetting.enable_sso = true
+        xhr :post, :create, login: user.username, password: 'myawesomepassword'
+      end
+      it_behaves_like "failed to continue local login"
+    end
+
     context 'when email is confirmed' do
       before do
         token = user.email_tokens.find_by(email: user.email)
@@ -524,14 +546,6 @@ describe SessionController do
         end
       end
 
-      describe 'local logins disabled' do
-        it 'fails' do
-          SiteSetting.enable_local_logins = false
-          xhr :post, :create, login: user.username, password: 'myawesomepassword'
-          expect(response.status.to_i).to eq(500)
-        end
-      end
-
       describe 'with a blocked IP' do
         before do
           screened_ip = Fabricate(:screened_ip_address)
@@ -727,10 +741,20 @@ describe SessionController do
     context 'for an existing username' do
       let(:user) { Fabricate(:user) }
 
-      it "returns a 500 if local logins are disabled" do
-        SiteSetting.enable_local_logins = false
-        xhr :post, :forgot_password, login: user.username
-        expect(response.code.to_i).to eq(500)
+      context 'local login is disabled' do
+        before do
+          SiteSetting.enable_local_logins = false
+          xhr :post, :forgot_password, login: user.username
+        end
+        it_behaves_like "failed to continue local login"
+      end
+
+      context 'SSO is enabled' do
+        before do
+          SiteSetting.enable_sso = true
+          xhr :post, :create, login: user.username, password: 'myawesomepassword'
+        end
+        it_behaves_like "failed to continue local login"
       end
 
       it "generates a new token for a made up username" do