Return an empty result set instead of 404 in case users are not available. (#5238)

A common response in collection endpoint with REST APIs is to return an empty result set when the requested params end up in an empty result. The reason for this is that the resource itself exists (the collection always exists), it just is empty.

See https://github.com/thepracticaldev/dev.to/pull/5192

app/controllers/api/v0/users_controller.rb

@@ -10,13 +10,14 @@ module Api
           @users = User.where(username: usernames)
           return
         end
+
         if params[:state] == "follow_suggestions"
           @users = Suggester::Users::Recent.new(current_user).suggest
         elsif params[:state] == "sidebar_suggestions"
           given_tag = params[:tag]
           @users = Suggester::Users::Sidebar.new(current_user, given_tag).suggest.sample(3)
         else
-          error_not_found
+          @users = User.none
         end
       end
 

spec/requests/api/v0/users_spec.rb

@@ -6,11 +6,10 @@ RSpec.describe "Api::V0::Users", type: :request do
   end
 
   describe "GET /api/users" do
-    it "returns not found status if state is not present" do
-      user = create(:user)
-      sign_in user
+    it "returns no users if state is not present" do
       get api_users_path, params: {}
-      expect(response.status).to eq(404)
+      expect(response).to have_http_status(:success)
+      expect(json_response).to be_empty
     end
   end