diff --git a/pkgs/tools/text/mdbook/default.nix b/pkgs/tools/text/mdbook/default.nix
index 57f373a9ce1a..c7e55426f47f 100644
--- a/pkgs/tools/text/mdbook/default.nix
+++ b/pkgs/tools/text/mdbook/default.nix
@@ -1,17 +1,17 @@
-{ lib, stdenv, fetchFromGitHub, rustPlatform, CoreServices }:
+{ lib, stdenv, fetchFromGitHub, nix, rustPlatform, CoreServices }:
 
 rustPlatform.buildRustPackage rec {
   pname = "mdbook";
-  version = "0.4.18";
+  version = "0.4.20";
 
   src = fetchFromGitHub {
     owner = "rust-lang";
     repo = "mdBook";
     rev = "v${version}";
-    sha256 = "sha256-lsryNrgjOGdugOhtkNbnYEreF0X1ywLVaFmKUXDf884=";
+    sha256 = "sha256-Cfi9qjY7+G7nGgxt4xNLIkGlpgr6TnvGlFrz3gMKCX8=";
   };
 
-  cargoSha256 = "sha256-l95nbp9PEgO97D1M/R9IB3Xfog6+DkZwyVY2DEl5mG4=";
+  cargoSha256 = "sha256-Ihs5aaruzj/8gbUhg4MmrYmpS9Hi/DohuEV2WtrxUXE=";
 
   buildInputs = lib.optionals stdenv.isDarwin [ CoreServices ];
 
@@ -21,6 +21,12 @@ rustPlatform.buildRustPackage rec {
   # is released.
   logLevel = "info";
 
+  passthru = {
+    tests = {
+      inherit nix;
+    };
+  };
+
   meta = with lib; {
     description = "Create books from MarkDown";
     homepage = "https://github.com/rust-lang/mdBook";