From ec738fac30887c9727a14d5a753861fb96e9e77d Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?J=C3=B6rg=20Thalheim?= <joerg@thalheim.io>
Date: Wed, 16 Apr 2025 14:34:21 +0200
Subject: [PATCH] impure-checks: limit number of workers to number of tests

---
 checks/impure/flake-module.nix | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/checks/impure/flake-module.nix b/checks/impure/flake-module.nix
index 93609cbae..b0736fe9b 100644
--- a/checks/impure/flake-module.nix
+++ b/checks/impure/flake-module.nix
@@ -19,6 +19,7 @@
             [
               pkgs.gitMinimal
               pkgs.nix
+              pkgs.coreutils
               pkgs.rsync # needed to have rsync installed on the dummy ssh server
             ]
             ++ self'.packages.clan-cli-full.runtimeDependencies
@@ -30,7 +31,12 @@
         # this disables dynamic dependency loading in clan-cli
         export CLAN_NO_DYNAMIC_DEPS=1
 
-        nix develop "$ROOT#clan-cli" -c bash -c "TMPDIR=/tmp python -m pytest -m impure ./clan_cli $@"
+        jobs=$(nproc)
+        # Spawning worker in pytest is relatively slow, so we limit the number of jobs to 13
+        # (current number of impure tests)
+        jobs="$((jobs > 13 ? 13 : jobs))"
+
+        nix develop "$ROOT#clan-cli" -c bash -c "TMPDIR=/tmp python -m pytest -n $jobs -m impure ./clan_cli $@"
       '';
     };
 }