pythonPackages.buildSetupcfg: Allow disabling tests.

pkgs/build-support/build-setupcfg/default.nix

@@ -5,18 +5,20 @@
 # * meta: Standard nixpkgs metadata.
 # * application: Whether this package is a python library or an
 #   application which happens to be written in python.
-pythonPackages: { src, info, meta ? {}, application ? false }: let
+# * doCheck: Whether to run the test suites.
+pythonPackages:
+{ src, info, meta ? {}, application ? false, doCheck ? true }: let
   build = if application
     then pythonPackages.buildPythonApplication
   else pythonPackages.buildPythonPackage;
 in build {
   inherit (info) pname version;
 
-  inherit src meta;
+  inherit src meta doCheck;
 
   nativeBuildInputs = map (p: pythonPackages.${p}) (
     (info.setup_requires or []) ++
-    (info.tests_require or []));
+    (if doCheck then (info.tests_require or []) else []));
 
   propagatedBuildInputs = map (p: pythonPackages.${p})
     (info.install_requires or []);