diff --git a/shell.nix b/shell.nix
index 7b90dc9c2c..61f0578763 100644
--- a/shell.nix
+++ b/shell.nix
@@ -1,7 +1,7 @@
 with import <nixpkgs> {};
 
 let
-  myPython = python36.withPackages(p: [p.trezor]);
+  myPython = python36.withPackages(ps: [ps.trezor ps.pytest]);
 in
   stdenv.mkDerivation {
     name = "trezor-core-dev";