add test and fix problem

src/nix/post-install-steps.sh

@@ -20,10 +20,10 @@ if [ ! -z "${PACKAGES}" ] && [ "${PACKAGES}" != "none" ]; then
   if [ "${USEATTRPATH}" = "true" ]; then
     PACKAGES=$(add_nixpkgs_prefix "$PACKAGES")
     echo "Installing packages \"${PACKAGES}\" in profile..."
-    nix-env -iA "${PACKAGES}"
+    nix-env -iA ${PACKAGES}
   else
     echo "Installing packages \"${PACKAGES}\" in profile..."
-    nix-env --install "${PACKAGES}"
+    nix-env --install ${PACKAGES}
   fi
 fi
 

test/nix/packages-use-attr-path.sh

@@ -0,0 +1,35 @@
+#!/bin/bash
+set -e
+
+# Optional: Import test library bundled with the devcontainer CLI
+source dev-container-features-test-lib
+
+uid="$(id -u)"
+echo "Current user UID is ${uid}."
+if [ "${uid}" != "1000" ]; then
+    echo "Current user UID was adjusted."
+fi
+set +e
+vscode_uid="$(id -u vscode)"
+set -e
+if [ "${vscode_uid}" != "" ]; then
+    echo "User vscode UID is ${vscode_uid}."
+    if [ "${vscode_uid}" != "1000" ]; then
+        echo "User vscode UID was adjusted."
+    fi
+fi
+nix_uid="$(stat /nix -c "%u")"
+echo "/nix UID is ${nix_uid}."
+
+cat /etc/os-release
+
+# Feature-specific tests
+# The 'check' command comes from the dev-container-features-test-lib.
+check "nix-env" type nix-env
+check "vim_installed" type vim
+check "node_installed" type node
+check "yarn_installed" type yarn
+
+# Report result
+# If any of the checks above exited with a non-zero exit code, the test will fail.
+reportResults &2>1

test/nix/scenarios.json

@@ -81,6 +81,17 @@
             }
         }
     },
+    "packages-use-attr-path": {
+        "image": "mcr.microsoft.com/devcontainers/base:ubuntu",
+        "remoteUser": "vscode",
+        "features": {
+            "nix": {
+                "packages": "nodePackages.nodejs,nixpkgs.vim,nixpkgs.yarn",
+                "useAttrPath": true
+            }
+        }
+    },
+
     "flake": {
         "image": "mcr.microsoft.com/devcontainers/base:ubuntu",
         "remoteUser": "vscode",