1 files changed, 3 insertions, 0 deletions
diff --git a/flake.nix b/flake.nix
index 9c918ff9..caa29fae 100644
--- a/flake.nix
+++ b/flake.nix
@@ -78,6 +78,9 @@
           duneVersion = "3";
           src = ./tests/test_runner;
           OCAMLPARAM = "_,warn-error=+A"; # Turn all warnings into errors.
+          propagatedBuildInputs = (with ocamlPackages; [
+            core_unix
+          ]);
         };
 
         # This test is a full crate with dependencies. We generate the