diff --git a/pkgs/tools/text/wdiff/default.nix b/pkgs/tools/text/wdiff/default.nix
index f4edc02b9fa..df2ef215069 100644
--- a/pkgs/tools/text/wdiff/default.nix
+++ b/pkgs/tools/text/wdiff/default.nix
@@ -1,4 +1,4 @@
-{ stdenv, fetchurl, texinfo }:
+{ stdenv, fetchurl, texinfo, which }:
 
 stdenv.mkDerivation rec {
   name = "wdiff-1.2.2";
@@ -10,6 +10,8 @@ stdenv.mkDerivation rec {
 
   buildInputs = [ texinfo ];
 
+  checkInputs = [ which ];
+
   meta = {
     homepage = http://www.gnu.org/software/wdiff/;
     description = "Comparing files on a word by word basis";