diff --git a/app/assets/javascripts/discourse/lib/bootstrap-json/index.js b/app/assets/javascripts/discourse/lib/bootstrap-json/index.js
index b2b243fdc56..1c778d80a02 100644
--- a/app/assets/javascripts/discourse/lib/bootstrap-json/index.js
+++ b/app/assets/javascripts/discourse/lib/bootstrap-json/index.js
@@ -429,6 +429,8 @@ module.exports = {
             `<script src="${config.rootURL}assets/plugins/test/${directoryName}_tests.js" data-discourse-plugin="${pluginName}"></script>`
         )
         .join("\n");
+    } else if (shouldLoadPluginTestJs() && type === "test-plugin-css") {
+      return `<link rel="stylesheet" href="${config.rootURL}bootstrap/plugin-css-for-tests.css" data-discourse-plugin="_all" />`;
     }
   },
 
diff --git a/app/assets/javascripts/discourse/public/assets/scripts/discourse-test-load-dynamic-js.js b/app/assets/javascripts/discourse/public/assets/scripts/discourse-test-load-dynamic-js.js
index fc0237c6225..8041b5141bd 100644
--- a/app/assets/javascripts/discourse/public/assets/scripts/discourse-test-load-dynamic-js.js
+++ b/app/assets/javascripts/discourse/public/assets/scripts/discourse-test-load-dynamic-js.js
@@ -3,26 +3,32 @@ const dynamicJsTemplate = document.querySelector("#dynamic-test-js");
 const params = new URLSearchParams(document.location.search);
 const skipPlugins = params.get("qunit_skip_plugins");
 
-for (const element of dynamicJsTemplate.content.childNodes) {
-  if (skipPlugins && element.dataset?.discoursePlugin) {
-    continue;
+(async function setup() {
+  for (const element of dynamicJsTemplate.content.childNodes) {
+    if (skipPlugins && element.dataset?.discoursePlugin) {
+      continue;
+    }
+
+    if (
+      element.tagName === "SCRIPT" &&
+      element.innerHTML.includes("EmberENV.TESTS_FILE_LOADED")
+    ) {
+      // Inline script introduced by ember-cli. Incompatible with CSP and our custom plugin JS loading system
+      // https://github.com/ember-cli/ember-cli/blob/04a38fda2c/lib/utilities/ember-app-utils.js#L131
+      // We re-implement in test-boot-ember-cli.js
+      continue;
+    }
+
+    const clone = element.cloneNode(true);
+
+    if (clone.tagName === "SCRIPT") {
+      clone.async = false;
+    }
+
+    document.querySelector("discourse-dynamic-test-js").appendChild(clone);
+
+    if (clone.tagName === "LINK" && clone["rel"] === "stylesheet") {
+      await new Promise((resolve) => (clone.onload = resolve));
+    }
   }
-
-  if (
-    element.tagName === "SCRIPT" &&
-    element.innerHTML.includes("EmberENV.TESTS_FILE_LOADED")
-  ) {
-    // Inline script introduced by ember-cli. Incompatible with CSP and our custom plugin JS loading system
-    // https://github.com/ember-cli/ember-cli/blob/04a38fda2c/lib/utilities/ember-app-utils.js#L131
-    // We re-implement in test-boot-ember-cli.js
-    continue;
-  }
-
-  const clone = element.cloneNode(true);
-
-  if (clone.tagName === "SCRIPT") {
-    clone.async = false;
-  }
-
-  document.querySelector("discourse-dynamic-test-js").appendChild(clone);
-}
+})();
diff --git a/app/assets/javascripts/discourse/testem.js b/app/assets/javascripts/discourse/testem.js
index fbc39514183..1bcc31d2cda 100644
--- a/app/assets/javascripts/discourse/testem.js
+++ b/app/assets/javascripts/discourse/testem.js
@@ -105,5 +105,11 @@ if (process.argv.includes("-t")) {
     "/plugins/": {
       target,
     },
+    "/bootstrap/plugin-css-for-tests.css": {
+      target,
+    },
+    "/stylesheets/": {
+      target,
+    },
   };
 }
diff --git a/app/assets/javascripts/discourse/tests/index.html b/app/assets/javascripts/discourse/tests/index.html
index 3277f0b1cc6..c286633609f 100644
--- a/app/assets/javascripts/discourse/tests/index.html
+++ b/app/assets/javascripts/discourse/tests/index.html
@@ -52,6 +52,7 @@
     <script src="{{rootURL}}assets/wizard.js"></script>
 
     <template id="dynamic-test-js">
+      {{content-for "test-plugin-css"}}
       {{content-for "test-plugin-js"}}
       <script defer src="{{rootURL}}assets/test-helpers.js"></script>
       <script defer src="{{rootURL}}assets/core-tests.js"></script>
diff --git a/app/controllers/bootstrap_controller.rb b/app/controllers/bootstrap_controller.rb
index 235308de3ff..8f7c4b4f62b 100644
--- a/app/controllers/bootstrap_controller.rb
+++ b/app/controllers/bootstrap_controller.rb
@@ -3,7 +3,7 @@
 class BootstrapController < ApplicationController
   include ApplicationHelper
 
-  skip_before_action :redirect_to_login_if_required
+  skip_before_action :redirect_to_login_if_required, :check_xhr
 
   # This endpoint allows us to produce the data required to start up Discourse via JSON API,
   # so that you don't have to scrape the HTML for `data-*` payloads
@@ -98,6 +98,23 @@ class BootstrapController < ApplicationController
     render_json_dump(bootstrap: bootstrap)
   end
 
+  def plugin_css_for_tests
+    urls = Discourse.find_plugin_css_assets(
+      include_disabled: true,
+      desktop_view: true,
+    ).map do |target|
+      details = Stylesheet::Manager.new().stylesheet_details(target, 'all')
+      details[0][:new_href]
+    end
+
+    stylesheet = <<~CSS
+      /* For use in tests only - `@import`s all plugin stylesheets */
+      #{urls.map { |url| "@import \"#{url}\";" }.join("\n") }
+    CSS
+
+    render plain: stylesheet, content_type: 'text/css'
+  end
+
 private
   def add_scheme(scheme_id, media, css_class)
     return if scheme_id.to_i == -1
diff --git a/config/routes.rb b/config/routes.rb
index cbb1ee51977..0092fec3f01 100644
--- a/config/routes.rb
+++ b/config/routes.rb
@@ -17,6 +17,9 @@ Discourse::Application.routes.draw do
     get "/404-body" => "exceptions#not_found_body"
 
     get "/bootstrap" => "bootstrap#index"
+    if Rails.env.test? || Rails.env.development?
+      get "/bootstrap/plugin-css-for-tests.css" => "bootstrap#plugin_css_for_tests"
+    end
 
     post "webhooks/aws" => "webhooks#aws"
     post "webhooks/mailgun"  => "webhooks#mailgun"
diff --git a/plugins/poll/test/javascripts/widgets/discourse-poll-test.js b/plugins/poll/test/javascripts/widgets/discourse-poll-test.js
index b75ada49602..546392129a1 100644
--- a/plugins/poll/test/javascripts/widgets/discourse-poll-test.js
+++ b/plugins/poll/test/javascripts/widgets/discourse-poll-test.js
@@ -1,7 +1,12 @@
 import { module, test } from "qunit";
 import { setupRenderingTest } from "discourse/tests/helpers/component-test";
 import { click, render } from "@ember/test-helpers";
-import { count, exists, query } from "discourse/tests/helpers/qunit-helpers";
+import {
+  count,
+  exists,
+  query,
+  queryAll,
+} from "discourse/tests/helpers/qunit-helpers";
 import hbs from "htmlbars-inline-precompile";
 import pretender, { response } from "discourse/tests/helpers/create-pretender";
 import EmberObject from "@ember/object";
@@ -85,7 +90,10 @@ module("Integration | Component | Widget | discourse-poll", function (hooks) {
     await click("li[data-poll-option-id='1f972d1df351de3ce35a787c89faad29']");
     assert.strictEqual(requests, 1);
     assert.strictEqual(count(".chosen"), 1);
-    assert.strictEqual(query(".chosen").innerText, "100%yes");
+    assert.deepEqual(
+      Array.from(queryAll(".chosen span")).map((span) => span.innerText),
+      ["100%", "yes"]
+    );
 
     await click(".toggle-results");
     assert.strictEqual(