diff --git a/requirements-tests.in b/requirements-tests.in
index 41b5c5778d13e356a8188bfd7452b615deb6d480..eb7961896371c2ea899ea51bd04f514eba1fb4d9 100644
--- a/requirements-tests.in
+++ b/requirements-tests.in
@@ -1,2 +1,6 @@
 codecov
 twisted
+attrs
+hypothesis
+testtools
+fixtures
diff --git a/setup.cfg b/setup.cfg
index e2df42db47b97f69717533155ee89c281eedb433..821a58ce2464ffc3da5745e54c0d7eb52e3c44f0 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -31,6 +31,7 @@ packages =
     twisted.plugins
 
 install_requires =
+    attrs
     zope.interface
     twisted
     tahoe-lafs