diff --git a/tahoe-lafs.nix b/tahoe-lafs.nix
index a0b23d65fc410209db3e4f4692f89ce1fc329a97..de4940d98bc36335c60480aaa0cdff90db3bae01 100644
--- a/tahoe-lafs.nix
+++ b/tahoe-lafs.nix
@@ -37,5 +37,14 @@ python.pkgs.buildPythonPackage rec {
     eliot autobahn cryptography
   ];
 
+  checkInputs = with python.pkgs; [
+    hypothesis
+    testtools
+    fixtures
+  ];
+
+  checkPhase = ''
+    ${python}/bin/python -m twisted.trial -j4 allmydata
+  '';
   doCheck = false;
 }