diff --git a/app/assets/javascripts/discourse/helpers/custom-html.js.es6 b/app/assets/javascripts/discourse/helpers/custom-html.js.es6
index 5a389ea49c2..4828ae057ec 100644
--- a/app/assets/javascripts/discourse/helpers/custom-html.js.es6
+++ b/app/assets/javascripts/discourse/helpers/custom-html.js.es6
@@ -1,7 +1,7 @@
 import { registerHelper } from 'discourse-common/lib/helpers';
 import PreloadStore from 'preload-store';
 
-const _customizations = {};
+let _customizations = {};
 
 export function getCustomHTML(key) {
   const c = _customizations[key];
@@ -15,6 +15,10 @@ export function getCustomHTML(key) {
   }
 }
 
+export function clearHTMLCache() {
+  _customizations = {};
+}
+
 // Set a fragment of HTML by key. It can then be looked up with `getCustomHTML(key)`.
 export function setCustomHTML(key, html) {
   _customizations[key] = html;
diff --git a/test/javascripts/acceptance/custom-html-set-test.js.es6 b/test/javascripts/acceptance/custom-html-set-test.js.es6
new file mode 100644
index 00000000000..3ae0bd63737
--- /dev/null
+++ b/test/javascripts/acceptance/custom-html-set-test.js.es6
@@ -0,0 +1,30 @@
+import { acceptance } from "helpers/qunit-helpers";
+import { setCustomHTML } from 'discourse/helpers/custom-html';
+import PreloadStore from 'preload-store';
+
+acceptance("CustomHTML set");
+
+test("has no custom HTML in the top", assert => {
+  visit("/static/faq");
+  andThen(() => {
+    assert.ok(!exists('span.custom-html-test'), 'it has no markup');
+  });
+});
+
+test("renders set HTML", assert => {
+  setCustomHTML('top', '<span class="custom-html-test">HTML</span>');
+
+  visit("/static/faq");
+  andThen(() => {
+    assert.equal(find('span.custom-html-test').text(), 'HTML', 'it inserted the markup');
+  });
+});
+
+test("renders preloaded HTML", assert => {
+  PreloadStore.store('customHTML', {top: "<span class='cookie'>monster</span>"});
+
+  visit("/static/faq");
+  andThen(() => {
+    assert.equal(find('span.cookie').text(), 'monster', 'it inserted the markup');
+  });
+});
diff --git a/test/javascripts/acceptance/custom-html-template-test.js.es6 b/test/javascripts/acceptance/custom-html-template-test.js.es6
new file mode 100644
index 00000000000..d125236ebbc
--- /dev/null
+++ b/test/javascripts/acceptance/custom-html-template-test.js.es6
@@ -0,0 +1,18 @@
+import { acceptance } from "helpers/qunit-helpers";
+
+acceptance("CustomHTML template", {
+  setup() {
+    Ember.TEMPLATES['top'] = Ember.HTMLBars.compile(`<span class='top-span'>TOP</span>`);
+  },
+
+  teardown() {
+    delete Ember.TEMPLATES['top'];
+  }
+});
+
+test("renders custom template", assert => {
+  visit("/static/faq");
+  andThen(() => {
+    assert.equal(find('span.top-span').text(), 'TOP', 'it inserted the template');
+  });
+});
diff --git a/test/javascripts/acceptance/plugin-outlet-single-template-test.js.es6 b/test/javascripts/acceptance/plugin-outlet-single-template-test.js.es6
index df63e013114..228506e27c9 100644
--- a/test/javascripts/acceptance/plugin-outlet-single-template-test.js.es6
+++ b/test/javascripts/acceptance/plugin-outlet-single-template-test.js.es6
@@ -1,22 +1,17 @@
 import { acceptance } from "helpers/qunit-helpers";
-import { clearCache } from 'discourse/helpers/plugin-outlet';
 
 const CONNECTOR = 'javascripts/single-test/connectors/user-profile-primary/hello';
 acceptance("Plugin Outlet - Single Template", {
   setup() {
-    clearCache();
     Ember.TEMPLATES[CONNECTOR] = Ember.HTMLBars.compile(
-      `
-        <span class='hello-username'>{{model.username}}</span>
+      `<span class='hello-username'>{{model.username}}</span>
         <button class='hello-check-email' {{action "checkEmail" model}}></button>
-        <span class='hello-email'>{{model.email}}</span>
-      `
+        <span class='hello-email'>{{model.email}}</span>`
     );
   },
 
   teardown() {
     delete Ember.TEMPLATES[CONNECTOR];
-    clearCache();
   }
 });
 
diff --git a/test/javascripts/helpers/custom-html-test.js.es6 b/test/javascripts/helpers/custom-html-test.js.es6
deleted file mode 100644
index 4c7f765e606..00000000000
--- a/test/javascripts/helpers/custom-html-test.js.es6
+++ /dev/null
@@ -1,16 +0,0 @@
-import { blank } from 'helpers/qunit-helpers';
-import PreloadStore from 'preload-store';
-
-module("helper:custom-html");
-
-import { getCustomHTML, setCustomHTML } from 'discourse/helpers/custom-html';
-
-test("customHTML", function() {
-  blank(getCustomHTML('evil'), "there is no custom HTML for a key by default");
-
-  setCustomHTML('evil', 'trout');
-  equal(getCustomHTML('evil'), 'trout', 'it retrieves the custom html');
-
-  PreloadStore.store('customHTML', {cookie: 'monster'});
-  equal(getCustomHTML('cookie'), 'monster', 'it returns HTML fragments from the PreloadStore');
-});
diff --git a/test/javascripts/helpers/qunit-helpers.js.es6 b/test/javascripts/helpers/qunit-helpers.js.es6
index 4a822c1266c..d8351405f0c 100644
--- a/test/javascripts/helpers/qunit-helpers.js.es6
+++ b/test/javascripts/helpers/qunit-helpers.js.es6
@@ -5,6 +5,8 @@ import siteFixtures from 'fixtures/site-fixtures';
 import HeaderComponent from 'discourse/components/site-header';
 import { forceMobile, resetMobile } from 'discourse/lib/mobile';
 import { resetPluginApi } from 'discourse/lib/plugin-api';
+import { clearCache as clearOutletCache } from 'discourse/helpers/plugin-outlet';
+import { clearHTMLCache } from 'discourse/helpers/custom-html';
 
 function currentUser() {
   return Discourse.User.create(sessionFixtures['/session/current.json'].current_user);
@@ -65,6 +67,8 @@ function acceptance(name, options) {
         }
       }
 
+      clearOutletCache();
+      clearHTMLCache();
       resetPluginApi();
       Discourse.reset();
     },
@@ -76,6 +80,8 @@ function acceptance(name, options) {
       Discourse.User.resetCurrent();
       Discourse.Site.resetCurrent(Discourse.Site.create(jQuery.extend(true, {}, fixtures['site.json'].site)));
 
+      clearOutletCache();
+      clearHTMLCache();
       resetPluginApi();
       Discourse.reset();
     }