ci: add a simple shell.nix for now for ci usage for e2e tests

Author: alehander92

ci/test/ui-tests.sh

@@ -27,7 +27,7 @@ set -e
 echo "========================"
 echo "RUNNING ui e2e tests"
 
-nix-shell -p xvfb-run --command "xvfb-run just test-e2e"
+nix-shell --command "xvfb-run just test-e2e"
 
 echo "========================"
 

ui-tests/shell.nix

@@ -0,0 +1,20 @@
+# copied and adapted from https://nix.dev/tutorials/first-steps/declarative-shell.html
+# however, using unstable like flake.nix
+let
+
+  nixpkgs = fetchTarball "https://github.com/NixOS/nixpkgs/tarball/nixos-unstable";
+
+  pkgs = import nixpkgs { config = {}; overlays = []; };
+
+in
+
+
+pkgs.mkShellNoCC {
+
+  packages = with pkgs; [
+
+    xvfb-run
+
+  ];
+
+}