Multiple Angular requests cause errors within tests - ruby-on-rails

Question

I've got an Angular 1.5 app with a Rails 4.0 backend and I've got this problem where in my tests once a Staff member logs in 3 queries are sent to the backend at the same time. In testing (using Capybara + selenium + chromeheadless) this causes these requests result in errors on the backend. In development it works fine.
An example of the error;
NoMethodError at /entities/get_current_entity
=============================================
> undefined method `fields' for nil:NilClass
app/controllers/application_controller.rb, line 79
--------------------------------------------------
``` ruby
74
75 private
76
77 def set_locale
78 #I18n.locale = params[:locale] if params[:locale].present?
> 79 if current_staff.nil? or current_staff.locale.nil?
80 I18n.locale = "en"
81 else
82 I18n.locale = current_staff.locale
83 end
84 end
```
App backtrace
-------------
- app/controllers/application_controller.rb:79:in `set_locale'
<Snip>
The test which fails
require "rails_helper"
RSpec.describe "Login", :type => :feature do
describe "login with existing staff member" do
before do
create_admin
end
it "logs in as admin" do
visit "#/login"
fill_in "Email", with: "admin#test.com.au"
fill_in "Password", with: "password"
click_button "Login"
within "#staff-status" do
expect(page).to have_text('LOGOUT')
end
within("#flash-messages") do
expect(page).to have_text('Successful login')
end
# Check session variables
within("#selected-entity") do
expect(page).to have_text("LOGIN DEFAULT COMPANY")
end
within("#selected-ledger") do
expect(page).to have_text("My Ledger")
end
within("#selected-division") do
expect(page).to have_text("1-General")
end
end
end
end
Here is the code which causes the pending calls
$scope.$on('devise:new-session', (event, currentStaff) ->
# staff logged in by Auth.login({...})
Auth.currentUser().then((staff) ->
FirmService.current_entity($rootScope)
DivisionService.current_division($rootScope)
LedgerService.current_ledger($rootScope)
$rootScope.current_staff = staff
, (error) ->
console.log("fail")
)
$location.path "/dashboard"
)
This happens all through the application and didn't happen on Rails 3.2. It's only since I'm going through this upgrade to Rails 4 that this has started to happen.
If I use promises then this problem doesn't happen. I cannot always use promises to get the data and this slows down the application also.
Here is the workaround for the login;
Auth.currentUser().then((staff) ->
FirmService.current_entity($rootScope).then ->
DivisionService.current_division($rootScope).then ->
LedgerService.current_ledger($rootScope)
How can I get Rails 4 to handle multiple requests like this in testing mode?
Update: Run server in test environment
I ran my server in the test environment to try and replicate the problem manually but it worked when doing it this way. So it must have something to do with either the speed of the test or capybara itself?
Update: Updated Gems
I updated to capybara 2.15.2, selenium-webdriver 3.6.0 & chromedriver-helper 1.1.0. This didn't help.
Update: Errors
Sometimes the error changes, I got an error 'Staff not logged in' on one of my requests even though the user is successfully logged in.
Update: Debugging
Inserting 'require "pry";binding.pry' into the Rails controllers where the AngularJS calls end up doesn't work as expected. I have three calls in the AngularJS code and I expect that Rails will hit the debug lines three times. The first time I ran it with the debug lines it only hit one of them, the second time it didn't hit any of the debug lines. Instead I got that NoMethodError at /entities/get_current_entity and the same for division and ledger.
Update: Looking into pry hanging
If I put a binding.pry into the set_locale method and call current_staff.locale.nil? I have found that sometimes pry will hang there forever.
After remarking out the set_locale contents it continues on and still fails and in the test.log file I get these errors;
Completed 500 Internal Server Error in 4690ms
Completed 500 Internal Server Error in 4688ms
Completed 500 Internal Server Error in 4686ms
NoMethodError - undefined method `fields' for nil:NilClass:
<snip>
NoMethodError - undefined method `fields' for nil:NilClass:
<snip>
NoMethodError - undefined method `collect' for nil:NilClass:
<snip>
(1.3ms) ALTER TABLE "indirect_taxes" DISABLE TRIGGER ALL;ALTER TABLE "ledger_defaults" DISABLE TRIGGER ALL;ALTER TABLE "ledgers" DISABLE TRIGGER ALL;ALTER TABLE "levels" DISABLE TRIGGER ALL;ALTER TABLE "locations" DISABLE TRIGGER ALL;ALTER TABLE "phones" DISABLE TRIGGER ALL;ALTER TABLE "sessions" DISABLE TRIGGER ALL;ALTER TABLE "transactions" DISABLE TRIGGER ALL;ALTER TABLE "versions" DISABLE TRIGGER ALL;ALTER TABLE "schema_migrations" DISABLE TRIGGER ALL;ALTER TABLE "staff" DISABLE TRIGGER ALL;ALTER TABLE "tickets" DISABLE TRIGGER ALL;ALTER TABLE "timesheets" DISABLE TRIGGER ALL;ALTER TABLE "websites" DISABLE TRIGGER ALL;ALTER TABLE "customers" DISABLE TRIGGER ALL;ALTER TABLE "costings" DISABLE TRIGGER ALL;ALTER TABLE "disbursements" DISABLE TRIGGER ALL;ALTER TABLE "employees" DISABLE TRIGGER ALL;ALTER TABLE "entities" DISABLE TRIGGER ALL;ALTER TABLE "folios" DISABLE TRIGGER ALL;ALTER TABLE "work_descs" DISABLE TRIGGER ALL;ALTER TABLE "account_groups" DISABLE TRIGGER ALL;ALTER TABLE "accounts" DISABLE TRIGGER ALL;ALTER TABLE "addresses" DISABLE TRIGGER ALL;ALTER TABLE "business_types" DISABLE TRIGGER ALL;ALTER TABLE "charges" DISABLE TRIGGER ALL;ALTER TABLE "comments" DISABLE TRIGGER ALL;ALTER TABLE "invoices" DISABLE TRIGGER ALL;ALTER TABLE "jobs" DISABLE TRIGGER ALL;ALTER TABLE "divisions" DISABLE TRIGGER ALL;ALTER TABLE "emails" DISABLE TRIGGER ALL
(411.5ms) TRUNCATE TABLE "public"."indirect_taxes", "public"."ledger_defaults", "public"."ledgers", "public"."levels", "public"."locations", "public"."phones", "public"."sessions", "public"."transactions", "public"."versions", "public"."staff", "public"."tickets", "public"."timesheets", "public"."websites", "public"."customers", "public"."costings", "public"."disbursements", "public"."employees", "public"."entities", "public"."folios", "public"."work_descs", "public"."account_groups", "public"."accounts", "public"."addresses", "public"."business_types", "public"."charges", "public"."comments", "public"."invoices", "public"."jobs", "public"."divisions", "public"."emails" RESTART IDENTITY CASCADE;
(1.9ms) ALTER TABLE "indirect_taxes" ENABLE TRIGGER ALL;ALTER TABLE "ledger_defaults" ENABLE TRIGGER ALL;ALTER TABLE "ledgers" ENABLE TRIGGER ALL;ALTER TABLE "levels" ENABLE TRIGGER ALL;ALTER TABLE "locations" ENABLE TRIGGER ALL;ALTER TABLE "phones" ENABLE TRIGGER ALL;ALTER TABLE "sessions" ENABLE TRIGGER ALL;ALTER TABLE "transactions" ENABLE TRIGGER ALL;ALTER TABLE "versions" ENABLE TRIGGER ALL;ALTER TABLE "staff" ENABLE TRIGGER ALL;ALTER TABLE "tickets" ENABLE TRIGGER ALL;ALTER TABLE "timesheets" ENABLE TRIGGER ALL;ALTER TABLE "schema_migrations" ENABLE TRIGGER ALL;ALTER TABLE "websites" ENABLE TRIGGER ALL;ALTER TABLE "customers" ENABLE TRIGGER ALL;ALTER TABLE "costings" ENABLE TRIGGER ALL;ALTER TABLE "disbursements" ENABLE TRIGGER ALL;ALTER TABLE "employees" ENABLE TRIGGER ALL;ALTER TABLE "entities" ENABLE TRIGGER ALL;ALTER TABLE "folios" ENABLE TRIGGER ALL;ALTER TABLE "work_descs" ENABLE TRIGGER ALL;ALTER TABLE "account_groups" ENABLE TRIGGER ALL;ALTER TABLE "accounts" ENABLE TRIGGER ALL;ALTER TABLE "addresses" ENABLE TRIGGER ALL;ALTER TABLE "business_types" ENABLE TRIGGER ALL;ALTER TABLE "charges" ENABLE TRIGGER ALL;ALTER TABLE "comments" ENABLE TRIGGER ALL;ALTER TABLE "invoices" ENABLE TRIGGER ALL;ALTER TABLE "jobs" ENABLE TRIGGER ALL;ALTER TABLE "divisions" ENABLE TRIGGER ALL;ALTER TABLE "emails" ENABLE TRIGGER ALL
I think that last bit with the Truncate table is the database cleaner trying to clean up the mess. So those three Server Errors I get seem to be timing out. Why would the database / Rails stop listening to the queries?
pry will also hang within the set_locale method when I type a simple query
Staff.all
Update: strace output
I've taken the strace output from when pry hangs;
https://gist.github.com/map7/f25f75457f1a6ae6995934e2c2744660

Answer 1

After chatting for a bit it turns out that a patch to share the DB connection between multiple threads was being used. The problem is, that can create all sorts of issue with multiple simultaneous requests, and generally lead to potential flakiness in tests. Removing the patch fixed the tests.
Once you migrate your way all the way up to Rails 5.1, then Rails handles the sharing of the connection in the test environment through mutexes, allowing transactional feature testing, and obviating the need for database_cleaner