add nix support for test/missing_unionfs_mergerfs closes #182

test/missing_unionfs_mergerfs.sh

@@ -21,20 +21,46 @@ cleanup() {
 
 trap 'cleanup' EXIT
 
+run_regular() {
+    new_bin_dir="$(mktemp -d)"
+    mkdir "$new_bin_dir/usr"
+    # -s makes symlinks
+    cp -rs /usr/bin "$new_bin_dir/usr/bin"
+
+    # Delete mergerfs and unionfs and set the new PATH to the temporary directory
+    rm -f "$new_bin_dir/usr/bin/mergerfs" 2>/dev/null
+    rm -f "$new_bin_dir/usr/bin/unionfs" 2>/dev/null
+
+    echo hi >expected
+    PATH="$new_bin_dir/usr/bin" "$TRY" -y "echo hi" >target 2>/dev/null || exit 1
+    diff -q expected target || exit 2
+}
+
+run_nix() {
+    cat > shell.nix <<'EOF'
+    { pkgs ? import <nixpkgs> {} }:
+    pkgs.mkShell {
+        buildInputs = with pkgs; [
+            attr
+            util-linux
+        ];
+    }
+EOF
+
+    echo hi >expected
+    # Run the command in a nix-shell with only the specified packages
+    nix-shell --pure shell.nix --run "\"$TRY\" -y \"echo hi\"" >target 2>/dev/null || exit 3
+    diff -q expected target || exit 4
+}
+
 # particularly important that we run in mktemp: in some test machines,
 # the cwd is mounted, hence inaccessable.
 try_workspace="$(mktemp -d)"
 cd "$try_workspace" || exit 9
 
-new_bin_dir="$(mktemp -d)"
-mkdir "$new_bin_dir/usr"
-# -s makes symlinks
-cp -rs /usr/bin "$new_bin_dir/usr/bin"
-
-# Delete mergerfs and unionfs and set the new PATH to the temporary directory
-rm -f "$new_bin_dir/usr/bin/mergerfs" 2>/dev/null
-rm -f "$new_bin_dir/usr/bin/unionfs" 2>/dev/null
-
-echo hi >expected
-PATH="$new_bin_dir/usr/bin" "$TRY" -y "echo hi" >target 2>/dev/null || exit 1
-diff -q expected target || exit 2
+if [ -e /etc/NIXOS ]
+then
+    run_nix
+else
+    run_regular
+fi