diff --git a/.gitmodules b/.gitmodules
index 4eac6535f..1576a5830 100644
--- a/.gitmodules
+++ b/.gitmodules
@@ -13,3 +13,6 @@
 [submodule "test/resource/mocha"]
 	path = test/resource/mocha
 	url = https://github.com/mochajs/mocha.git
+[submodule "test/resource/chai-as-promised"]
+	path = test/resource/chai-as-promised
+	url = https://github.com/domenic/chai-as-promised.git
diff --git a/test/content/runtests.html b/test/content/runtests.html
index fa84b94f8..0ad279d07 100644
--- a/test/content/runtests.html
+++ b/test/content/runtests.html
@@ -7,6 +7,7 @@
 	<script src="jquery.js"></script>
 	<script src="chrome://zotero/content/include.js"></script>
 	<script src="resource://zotero-unit/chai/chai.js"></script>
+	<script src="resource://zotero-unit/chai-as-promised/lib/chai-as-promised.js"></script>
 	<script src="resource://zotero-unit/mocha/mocha.js"></script>
 	<script src="resource://zotero-unit/sinon.js"></script>
 	<script src="support.js" type="application/javascript;version=1.8"></script>
diff --git a/test/resource/chai-as-promised b/test/resource/chai-as-promised
new file mode 160000
index 000000000..5dcfee7fa
--- /dev/null
+++ b/test/resource/chai-as-promised
@@ -0,0 +1 @@
+Subproject commit 5dcfee7fa3f3532964680dff2c13547677c0157e