test(scripts): lock package-inventory behavior with characterization tests

package-inventory compares archsetup's declared packages against the live system but had no tests, so a future archsetup edit (a new for-loop shape, a renamed install helper) could silently break the extraction.

I added two env seams so the script is testable without the real system. PKGINV_ARCHSETUP points the extractor at a fixture installer, PKGINV_PACMAN swaps in a fake pacman serving controlled query output. Both default to the real targets, so normal use is unchanged, and the seams match the env-override pattern audit-packages.sh already uses.

The 7 tests pin the extraction (direct calls, for-loop lists, variable-arg skip) and both diff directions against the fixture, with no network or real pacman db. I also added a make package-diff target so the tool is reachable alongside the test targets.

1 files changed, 10 insertions, 5 deletions

diff --git a/scripts/package-inventory b/scripts/package-inventory
index 4742645..2dda44b 100755
--- a/scripts/package-inventory
+++ b/scripts/package-inventory
@@ -8,7 +8,12 @@
 set -euo pipefail
 
 SCRIPT_DIR="$(cd "$(dirname "$0")/.." && pwd)"
-ARCHSETUP="$SCRIPT_DIR/archsetup"
+
+# Seams for testing: PKGINV_ARCHSETUP points the extractor at a fixture
+# installer; PKGINV_PACMAN swaps in a fake pacman serving controlled
+# -Qqe/-Qq/-Qqen/-Qqem output. Both default to the real targets.
+ARCHSETUP="${PKGINV_ARCHSETUP:-$SCRIPT_DIR/archsetup}"
+PACMAN="${PKGINV_PACMAN:-pacman}"
 
 # Colors
 RED='\033[0;31m'
@@ -66,22 +71,22 @@ extract_archsetup_packages() {
 # Get packages on live system
 # ============================================================================
 get_system_packages_explicit() {
-    pacman -Qqe | sort -u  # explicitly installed
+    "$PACMAN" -Qqe | sort -u  # explicitly installed
 }
 
 get_system_packages_all() {
-    pacman -Qq | sort -u   # all installed (including deps)
+    "$PACMAN" -Qq | sort -u   # all installed (including deps)
 }
 
 # ============================================================================
 # Categorize system packages
 # ============================================================================
 get_system_native() {
-    pacman -Qqen | sort -u  # native (official repos)
+    "$PACMAN" -Qqen | sort -u  # native (official repos)
 }
 
 get_system_foreign() {
-    pacman -Qqem | sort -u  # foreign (AUR/manual)
+    "$PACMAN" -Qqem | sort -u  # foreign (AUR/manual)
 }
 
 # ============================================================================