add specs of session controller

app/controllers/root_controller.rb

@@ -1,4 +1,5 @@
 class RootController < ApplicationController
+  # GET /
   def index
     if @current_user
       if params[:tag].nil?

app/controllers/sessions_controller.rb

@@ -1,4 +1,5 @@
 class SessionsController < ApplicationController
+  # GET /auth/github/callback
   def create
     auth = request.env["omniauth.auth"]
     user = User.find_by_uid(auth[:uid])
@@ -11,6 +12,7 @@ def create
     redirect_to root_path, notice: "Sign in was successful."
   end
 
+  # GET /logout
   def destroy
     session[:user] = nil
     redirect_to root_path

spec/controllers/sessions_controller_spec.rb

@@ -7,20 +7,64 @@ def valid_session
     {user: user.id}
   end
 
+  describe "GET create" do
+    context "with registered user" do
+      before do
+        User.any_instance.should_receive(:update_with_omniauth).and_return(true)
+        request.env["omniauth.auth"] = {uid: user.uid}
+        get :create
+      end
+
+      it "return http redirect" do
+        expect(response).to be_redirect
+      end
+
+      it "should redirect to root_path" do
+        expect(response).to redirect_to(root_path)
+      end
+
+      it "session should be created" do
+        expect(session[:user]).to eq(user.id)
+      end
+    end
+
+    context "with not registered user" do
+      before do
+        User.should_receive(:find_by_uid).and_return(nil)
+        User.should_receive(:create_with_omniauth).and_return(user)
+        request.env["omniauth.auth"] = {uid: "1"}
+        get :create
+      end
+
+      it "return http redirect" do
+        expect(response).to be_redirect
+      end
+
+      it "should redirect to root_path" do
+        expect(response).to redirect_to(root_path)
+      end
+
+      it "session should be created" do
+        expect(session[:user]).to eq(user.id)
+      end
+    end
+  end
+
   describe "GET destroy" do
-    it "returns http redirect" do
+    before do
+      session[:user] = user.id
       get :destroy, {}, valid_session
+    end
+
+    it "returns http redirect" do
       expect(response).to be_redirect
     end
 
     it "should redirect to root_path" do
-      get :destroy, {}, valid_session
       expect(response).to redirect_to(root_path)
     end
 
     it "should clear session" do
-      session[:user] = user.id
-      get :destroy, {}, valid_session
       expect(session[:user]).to be_nil
     end
   end