diff --git a/pkgs/development/haskell-modules/configuration-common.nix b/pkgs/development/haskell-modules/configuration-common.nix
index 26f852cfa73e..0f856d32f183 100644
--- a/pkgs/development/haskell-modules/configuration-common.nix
+++ b/pkgs/development/haskell-modules/configuration-common.nix
@@ -722,6 +722,13 @@ with haskellLib;
           --replace-fail 'InstallDesktopFile $(PREFIX)/bin/git-annex' \
                          'InstallDesktopFile git-annex'
       '';
+
+      # Work around race condition in test suite exposed by tasty-1.5.4
+      # TODO(@sternenseemann): make testFlags arg usable with git-annex
+      preCheck = ''
+        ${drv.preCheck or ""}
+        appendToVar checkFlags -j1
+      '';
     }))
   ];