diff --git a/package.json b/package.json
index c3f161ee..a39863d3 100644
--- a/package.json
+++ b/package.json
@@ -27,7 +27,7 @@
     "test": "ember try:each"
   },
   "dependencies": {
-    "@ember/test-helpers": "^0.7.25",
+    "@ember/test-helpers": "^0.7.26",
     "broccoli-funnel": "^2.0.1",
     "broccoli-merge-trees": "^2.0.0",
     "common-tags": "^1.4.0",
diff --git a/yarn.lock b/yarn.lock
index 50b107d8..a3a527fd 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -2,12 +2,13 @@
 # yarn lockfile v1
 
 
-"@ember/test-helpers@^0.7.25":
-  version "0.7.25"
-  resolved "https://registry.yarnpkg.com/@ember/test-helpers/-/test-helpers-0.7.25.tgz#b4014c108b40ffaf74f3c4d5918800917541541d"
-  integrity sha1-tAFMEItA/69088TVkYgAkXVBVB0=
+"@ember/test-helpers@^0.7.26":
+  version "0.7.26"
+  resolved "https://registry.yarnpkg.com/@ember/test-helpers/-/test-helpers-0.7.26.tgz#ae11cbde9cce2c872abbea6edcd849a31dd7bd1e"
+  integrity sha512-5HxPYmdeinI4f0lF2tKHyiNGTcNY3O5rw89AC6Z6hb9yEL3ktF8eaU7rZfvSTFEF3d3TlhR5Qidl27QzLGkUeA==
   dependencies:
     broccoli-funnel "^2.0.1"
+    ember-assign-polyfill "~2.4.0"
     ember-cli-babel "^6.12.0"
     ember-cli-htmlbars-inline-precompile "^1.0.0"
 
@@ -2177,6 +2178,14 @@ electron-to-chromium@^1.3.47:
   resolved "https://registry.yarnpkg.com/electron-to-chromium/-/electron-to-chromium-1.3.70.tgz#ded377256d92d81b4257d36c65aa890274afcfd2"
   integrity sha512-WYMjqCnPVS5JA+XvwEnpwucJpVi2+q9cdCFpbhxgWGsCtforFBEkuP9+nCyy/wnU/0SyLcLRIeZct9ayMGcXoQ==
 
+ember-assign-polyfill@~2.4.0:
+  version "2.4.0"
+  resolved "https://registry.yarnpkg.com/ember-assign-polyfill/-/ember-assign-polyfill-2.4.0.tgz#acb00466f7d674b3e6b030acfe255b3b1f6472e1"
+  integrity sha512-0SnGQb9CenRqbZdIa1KFsEjT+1ijGWfAbCSaDbg5uVa5l6HPdppuTzOXK6sfEQMsd2nbrp27QWFy7W5VX6l4Ag==
+  dependencies:
+    ember-cli-babel "^6.6.0"
+    ember-cli-version-checker "^2.0.0"
+
 ember-cli-babel@^6.0.0, ember-cli-babel@^6.12.0, ember-cli-babel@^6.4.1, ember-cli-babel@^6.6.0, ember-cli-babel@^6.8.1, ember-cli-babel@^6.8.2, ember-cli-babel@^6.9.0:
   version "6.17.2"
   resolved "https://registry.yarnpkg.com/ember-cli-babel/-/ember-cli-babel-6.17.2.tgz#f0d53d2fb95e70c15d8db84760d045f88f458f69"