diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index fc8424a..a667ed8 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -13,6 +13,7 @@ jobs:
         os: [ ubuntu-latest ]
         # FIXME macos garbage currently collect also nix-shell that runs the test
         #os: [ ubuntu-latest, macos-latest ]
+        nix: [ stable, unstable ]
     runs-on: ${{ matrix.os }}
     steps:
     - uses: actions/checkout@v3
@@ -24,4 +25,4 @@ jobs:
           keep-derivations = true
           experimental-features = nix-command flakes
     - run:
-        "nix run --accept-flake-config .#test-runner"
+        "nix run --accept-flake-config .#test-runner-${{ matrix.nix }}"
diff --git a/bors.toml b/bors.toml
index b133757..8a57a6f 100644
--- a/bors.toml
+++ b/bors.toml
@@ -4,7 +4,8 @@ status = [
   "check lint [x86_64-linux]",
   "devShell default [x86_64-linux]",
   "package default [x86_64-linux]",
-  "package test-runner [x86_64-linux]",
+  "package test-runner-stable [x86_64-linux]",
   "package test-runner-unstable [x86_64-linux]",
-  "tests (ubuntu-latest)"
+  "tests (ubuntu-latest, stable)",
+  "tests (ubuntu-latest, unstable)"
 ]
diff --git a/flake.nix b/flake.nix
index 705a139..e25d39e 100644
--- a/flake.nix
+++ b/flake.nix
@@ -15,8 +15,12 @@
         {
           packages = {
             default = pkgs.callPackage ./default.nix { };
-            test-runner = pkgs.callPackage ./test-runner.nix { };
-            test-runner-unstable = pkgs.callPackage ./test-runner.nix { };
+            test-runner-stable = pkgs.callPackage ./test-runner.nix {
+              nixVersion = "stable";
+            };
+            test-runner-unstable = pkgs.callPackage ./test-runner.nix { 
+              nixVersion = "unstable";
+            };
           };
           devShells.default = pkgs.callPackage ./shell.nix { };
           apps.test-runner = {
diff --git a/test-runner.nix b/test-runner.nix
index 53374a6..19520a6 100644
--- a/test-runner.nix
+++ b/test-runner.nix
@@ -1,14 +1,15 @@
-{ writeScript
+{ writeShellScriptBin
 , direnv
 , python3
 , lib
-, nix
 , coreutils
 , gnugrep
+, nixVersions
+, nixVersion
 }:
-writeScript "test-runner" ''
+writeShellScriptBin "test-runner-${nixVersion}" ''
   set -e
-  export PATH=${lib.makeBinPath [ direnv nix coreutils gnugrep ]}
+  export PATH=${lib.makeBinPath [ direnv nixVersions.${nixVersion} coreutils gnugrep ]}
 
   echo run unittest
   ${lib.getExe python3.pkgs.pytest} .