diff --git a/pkgs/development/python-modules/markdown-it-py/default.nix b/pkgs/development/python-modules/markdown-it-py/default.nix
index 1f2bc34b000b..c1c5da228f0f 100644
--- a/pkgs/development/python-modules/markdown-it-py/default.nix
+++ b/pkgs/development/python-modules/markdown-it-py/default.nix
@@ -12,6 +12,9 @@
 , pytestCheckHook
 , pythonOlder
 , typing-extensions
+# allow disabling tests for the nixos manual build.
+# the test suite closure is just too large.
+, disableTests ? false
 }:
 
 buildPythonPackage rec {
@@ -43,6 +46,7 @@ buildPythonPackage rec {
   nativeCheckInputs = [
     psutil
     py
+  ] ++ lib.optionals (! disableTests) [
     pytest-benchmark
     pytest-regressions
     pytestCheckHook
diff --git a/pkgs/development/python-modules/mdit-py-plugins/default.nix b/pkgs/development/python-modules/mdit-py-plugins/default.nix
index 291ea54c56bc..f93751ca71d5 100644
--- a/pkgs/development/python-modules/mdit-py-plugins/default.nix
+++ b/pkgs/development/python-modules/mdit-py-plugins/default.nix
@@ -6,6 +6,9 @@
 , markdown-it-py
 , pytest-regressions
 , pytestCheckHook
+# allow disabling tests for the nixos manual build.
+# the test suite closure is just too large.
+, disableTests ? false
 }:
 
 buildPythonPackage rec {
@@ -30,7 +33,7 @@ buildPythonPackage rec {
     markdown-it-py
   ];
 
-  nativeCheckInputs = [
+  nativeCheckInputs = lib.optionals (!disableTests) [
     pytestCheckHook
     pytest-regressions
   ];