diff --git a/pkgs/development/python-modules/requests-toolbelt/default.nix b/pkgs/development/python-modules/requests-toolbelt/default.nix
index 5a87d0a0e05b..3ad219025a92 100644
--- a/pkgs/development/python-modules/requests-toolbelt/default.nix
+++ b/pkgs/development/python-modules/requests-toolbelt/default.nix
@@ -24,7 +24,9 @@ buildPythonPackage rec {
     # disabled tests access the network
     py.test tests -k "not test_no_content_length_header \
                   and not test_read_file \
-                  and not test_reads_file_from_url_wrapper"
+                  and not test_reads_file_from_url_wrapper \
+                  and not test_x509_der \
+                  and not test_x509_pem"
   '';
 
   meta = {