Fix authentication specs with new routing

Move host ENV setup into a `.env.test` file for more simple setup.

Use the placements service for auth specs.

.env.test

@@ -0,0 +1,2 @@
+PLACEMENTS_HOST=placements.localhost
+CLAIMS_HOST=claims.localhost

app/controllers/application_controller.rb

@@ -1,4 +1,6 @@
 class ApplicationController < ActionController::Base
+  include ApplicationHelper
+
   default_form_builder(GOVUKDesignSystemFormBuilder::FormBuilder)
 
   helper_method :current_user

app/helpers/application_helper.rb

@@ -7,4 +7,11 @@ def current_service
       :placements
     end
   end
+
+  def root_path
+    case current_service
+    when :claims then claims_root_path
+    when :placements then placements_root_path
+    end
+  end
 end

spec/features/personas/sign_in_as_persona_spec.rb

@@ -3,6 +3,12 @@
 require "rails_helper"
 
 feature "Sign In as Persona" do
+  around do |example|
+    Capybara.app_host = "https://#{ENV["PLACEMENTS_HOST"]}"
+    example.run
+    Capybara.app_host = nil
+  end
+
   scenario "I sign in as persona Anne" do
     given_there_is_an_existing_persona_for("Anne")
     when_i_visit_the_personas_page

spec/requests/sessions_spec.rb

@@ -1,6 +1,12 @@
 require "rails_helper"
 
 RSpec.describe "Sessions", type: :request do
+  around do |example|
+    host! ENV["PLACEMENTS_HOST"]
+    example.run
+    host! nil
+  end
+
   describe "POST /auth/developer/callback" do
     it "returns http success" do
       post auth_developer_callback_path,
@@ -14,7 +20,7 @@
       expect(response).to have_http_status(:success)
       # TODO: Change render_template once redirect to service specific
       # roots implemented
-      expect(response).to render_template("pages/home")
+      expect(response).to render_template("placements/pages/index")
     end
   end
 end

spec/system/home_page_spec.rb

@@ -22,12 +22,10 @@
   private
 
   def given_i_am_on_the_claims_site
-    ENV["CLAIMS_HOST"] = "claims.localhost"
     Capybara.app_host = "http://#{ENV["CLAIMS_HOST"]}"
   end
 
   def given_i_am_on_the_placements_site
-    ENV["PLACEMENTS_HOST"] = "placements.localhost"
     Capybara.app_host = "http://#{ENV["PLACEMENTS_HOST"]}"
   end