Make #update specs consistent

* Use expect syntax
* Avoid lets
* Stub Guardian method used in the controller

spec/controllers/users_controller_spec.rb

@@ -824,40 +824,43 @@ describe UsersController do
 
   end
 
-  describe '.update' do
-
-    context 'not logged in' do
-      it 'raises an error when not logged in' do
+  describe '#update' do
+    context 'with guest' do
+      it 'raises an error' do
         expect do
-          xhr :put, :update, username: 'somename'
+          xhr :put, :update, username: 'guest'
         end.to raise_error(Discourse::NotLoggedIn)
       end
     end
 
-    context 'logged in' do
-      let!(:user) { log_in }
+    context 'with authenticated user' do
+      context 'with permission to update' do
+        it 'allows the update' do
+          user = Fabricate(:user, name: 'Billy Bob')
+          log_in_user(user)
+          guardian = Guardian.new(user)
+          guardian.stubs(:ensure_can_edit!)
+          Guardian.stubs(new: guardian).with(user)
 
-      context 'without a token' do
-        it 'should ensure you can update the user' do
-          Guardian.any_instance.expects(:can_edit?).with(user).returns(false)
-          put :update, username: user.username
-          response.should be_forbidden
+          put :update, username: user.username, name: 'Jim Tom'
+
+          expect(response).to be_success
+          expect(user.reload.name).to eq 'Jim Tom'
+        end
       end
 
-        context 'as a user who can edit the user' do
+      context 'without permission to update' do
+        it 'does not allow the update' do
+          user = Fabricate(:user, name: 'Billy Bob')
+          log_in_user(user)
+          guardian = Guardian.new(user)
+          guardian.stubs(:ensure_can_edit!).raises(Discourse::InvalidAccess.new)
+          Guardian.stubs(new: guardian).with(user)
 
-          before do
-            put :update, username: user.username, bio_raw: 'brand new bio'
-            user.reload
-          end
+          put :update, username: user.username, name: 'Jim Tom'
 
-          it 'updates the user' do
-            user.bio_raw.should == 'brand new bio'
-          end
-
-          it 'returns json success' do
-            response.should be_success
-          end
+          expect(response).to be_forbidden
+          expect(user.reload.name).not_to eq 'Jim Tom'
         end
       end
     end
@@ -1102,5 +1105,4 @@ describe UsersController do
     end
 
   end
-
 end