FIX: Theme tests should work in production (#13333)

The `ember_jquery` bundle contains production builds of Ember and jQuery
which doesn't work with tests. This commits introduces a new
`theme_qunit_vendor` bundle which is copy of the `vendor` bundle but
doesn't contain `ember_jquery`.

This commit is a partial revert of
409c8585e4

app/assets/javascripts/discourse/tests/theme_qunit_ember_jquery.js

@@ -0,0 +1,6 @@
+// discourse-skip-module
+
+//= require env
+//= require jquery.debug
+//= require ember.debug
+//= require discourse-loader

app/assets/javascripts/discourse/tests/theme_qunit_tests_vendor.js

@@ -0,0 +1,15 @@
+// discourse-skip-module
+
+//= require qunit
+//= require ember-qunit
+//= require fake_xml_http_request
+//= require route-recognizer
+//= require pretender
+
+// These are not loaded in prod or development
+// But we need them for testing handlebars templates in qunit
+//= require handlebars
+//= require ember-template-compiler
+
+//= require sinon
+//= require break_string

app/assets/javascripts/discourse/tests/theme_qunit_vendor.js

@@ -1,15 +1,37 @@
-// discourse-skip-module
+// This bundle contains the same dependencies as app/assets/javascripts/vendor.js
+// minus ember_jquery.
+// ember_jquery doesn't work with theme tests in production because it
+// contains production builds of Ember and jQuery, so we have a separate bundle
+// caled theme_qunit_ember_jquery which contains a debug build for Ember and jQuery.
+// We don't put theme_qunit_ember_jquery in this bundle because it would make the
+// bundle too big and cause OOM exceptions during rebuilds for self-hosters on
+// low-end machines.
 
-//= require qunit
+//= require logster
-//= require ember-qunit
-//= require fake_xml_http_request
-//= require route-recognizer
-//= require pretender
 
-// These are not loaded in prod or development
+//= require template_include.js
-// But we need them for testing handlebars templates in qunit
-//= require handlebars
-//= require ember-template-compiler
 
-//= require sinon
+//= require message-bus
-//= require break_string
+//= require jquery.ui.widget.js
+//= require Markdown.Converter.js
+//= require bootbox.js
+//= require popper.js
+//= require bootstrap-modal.js
+//= require caret_position
+//= require jquery.color.js
+//= require jquery.fileupload.js
+//= require jquery.iframe-transport.js
+//= require jquery.tagsinput.js
+//= require jquery.sortable.js
+//= require lodash.js
+//= require mousetrap.js
+//= require mousetrap-global-bind.js
+//= require rsvp.js
+//= require show-html.js
+//= require buffered-proxy
+//= require jquery.autoellipsis-1.0.10
+//= require virtual-dom
+//= require virtual-dom-amd
+//= require intersection-observer
+//= require discourse-shims
+//= require pretty-text-bundle

app/views/qunit/theme.html.erb

@@ -7,8 +7,9 @@
       <%= discourse_stylesheet_link_tag(:desktop, theme_ids: nil) %>
       <%= discourse_stylesheet_link_tag(:test_helper, theme_ids: nil) %>
       <%= preload_script "locales/en" %>
-      <%= preload_script "vendor" %>
+      <%= preload_script "discourse/tests/theme_qunit_ember_jquery" %>
       <%= preload_script "discourse/tests/theme_qunit_vendor" %>
+      <%= preload_script "discourse/tests/theme_qunit_tests_vendor" %>
       <%= preload_script "markdown-it-bundle" %>
       <%= preload_script "application" %>
       <%- Discourse.find_plugin_js_assets(include_official: allow_plugins?, include_unofficial: allow_third_party_plugins?, request: request).each do |file| %>

config/application.rb

@@ -173,8 +173,10 @@ module Discourse
       confirm-new-email/bootstrap.js
       onpopstate-handler.js
       embed-application.js
-      discourse/tests/theme_qunit_helper.js
+      discourse/tests/theme_qunit_ember_jquery.js
       discourse/tests/theme_qunit_vendor.js
+      discourse/tests/theme_qunit_tests_vendor.js
+      discourse/tests/theme_qunit_helper.js
       discourse/tests/test_starter.js
     }
 

spec/requests/qunit_controller_spec.rb

@@ -98,8 +98,9 @@ describe QunitController do
         expect(response.body).to include("/stylesheets/desktop_")
         expect(response.body).to include("/stylesheets/test_helper_")
         expect(response.body).to include("/assets/locales/en.js")
-        expect(response.body).to include("/assets/vendor.js")
+        expect(response.body).to include("/assets/discourse/tests/theme_qunit_ember_jquery.js")
         expect(response.body).to include("/assets/discourse/tests/theme_qunit_vendor.js")
+        expect(response.body).to include("/assets/discourse/tests/theme_qunit_tests_vendor.js")
         expect(response.body).to include("/assets/markdown-it-bundle.js")
         expect(response.body).to include("/assets/application.js")
         expect(response.body).to include("/assets/admin.js")