diff --git a/.github/workflows/install-test.yml b/.github/workflows/install-test.yml
new file mode 100644
index 0000000..9ba111e
--- /dev/null
+++ b/.github/workflows/install-test.yml
@@ -0,0 +1,44 @@
+name: Test Patches - Post Build
+
+# Runs automatically after every "Test Release Build" run completes (that build
+# is itself triggered by the 'make-test-build' label on a PR). Reuses the .deb
+# that build produced — no rebuild — installs it on a runner seeded with the
+# latest upstream Proxmox files, and verifies that every mod's patches (and
+# post-apply hooks) apply and revert cleanly. Fails if any mod fails.
+#
+# Wired via workflow_run, so it fires for builds on ANY branch/PR. (GitHub always
+# runs the default-branch copy of this file, so it activates once merged to main.)
+
+on:
+  workflow_run:
+    workflows: ["Test Release Build"]
+    types: [completed]
+
+permissions:
+  contents: read
+  actions: read   # required to download the triggering run's artifact
+
+jobs:
+  patch-install-test:
+    runs-on: ubuntu-latest
+    if: github.event.workflow_run.conclusion == 'success'
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Download deb from the build run
+        uses: actions/download-artifact@v4
+        with:
+          run-id: ${{ github.event.workflow_run.id }}
+          github-token: ${{ secrets.GITHUB_TOKEN }}
+          pattern: pve-mods-test-build-*
+          merge-multiple: true
+          path: deb
+
+      - name: Fetch upstream Proxmox files
+        run: bash src/Scripts/test/fetch-proxmox-files.sh
+
+      - name: Install built package
+        run: sudo apt-get install -y ./deb/*.deb
+
+      - name: Test all mods
+        run: sudo bash src/Scripts/test/test-mods.sh all
diff --git a/.github/workflows/weekly-patch-test.yml b/.github/workflows/weekly-patch-test.yml
new file mode 100644
index 0000000..2b239dd
--- /dev/null
+++ b/.github/workflows/weekly-patch-test.yml
@@ -0,0 +1,110 @@
+name: Test Patches - Weekly
+
+# Weekly regression test of pve-mod against the latest upstream Proxmox VE files.
+# Mods are auto-discovered from the [modules] section of src/pve-mod.conf and
+# tested in parallel - adding a mod needs no change here. If a mod fails, an
+# issue is opened (or updated) per failed mod explaining why.
+
+on:
+  schedule:
+    - cron: '0 6 * * 1'   # Mondays 06:00 UTC
+  workflow_dispatch:
+
+permissions:
+  contents: read
+  issues: write
+
+jobs:
+  discover:
+    runs-on: ubuntu-latest
+    outputs:
+      mods: ${{ steps.list.outputs.mods }}
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Discover mods from [modules]
+        id: list
+        run: |
+          MODS=$(awk -F= '
+            /^\[/ { in_sec = ($0 == "[modules]") }
+            in_sec && /^[^#=]+=/ {
+              gsub(/^[[:space:]]+|[[:space:]]+$/, "", $1); print $1
+            }' src/pve-mod.conf | jq -R . | jq -cs .)
+          echo "Discovered mods: $MODS"
+          echo "mods=$MODS" >> "$GITHUB_OUTPUT"
+
+  test:
+    needs: discover
+    runs-on: ubuntu-latest
+    strategy:
+      fail-fast: false
+      matrix:
+        mod: ${{ fromJSON(needs.discover.outputs.mods) }}
+    steps:
+      - uses: actions/checkout@v4
+        with:
+          fetch-depth: 0
+
+      # ── Build (mirrors test-release.yml) ───────────────────────────────────
+      - name: Install build deps
+        run: sudo apt-get install -y devscripts debhelper build-essential
+
+      - name: Inject version into PVEMod_Config.pm
+        run: |
+          VERSION=$(grep -m1 '(' debian/changelog | sed 's/.*(\(.*\)).*/\1/')
+          SHORT_SHA=$(git rev-parse --short HEAD)
+          export BUILD_VERSION="${VERSION}-test-${SHORT_SHA}"
+          perl -i -pe 'BEGIN { $v = $ENV{BUILD_VERSION} }
+            s/(our \$VERSION\s*=\s*'"'"')[^'"'"']*'"'"';/$1'"'"'$v'"'"';/
+          ' src/PVENodeInfo/PVEMod_Config.pm
+
+      - name: Build package
+        run: dpkg-buildpackage -us -uc -b
+
+      # ── Test ───────────────────────────────────────────────────────────────
+      - name: Fetch upstream Proxmox files
+        run: bash src/Scripts/test/fetch-proxmox-files.sh
+
+      - name: Install built package
+        run: sudo apt-get install -y ../pve-mod_*.deb
+
+      - name: Test mod
+        run: |
+          set -o pipefail
+          sudo bash src/Scripts/test/test-mods.sh "${{ matrix.mod }}" 2>&1 | tee test-output.log
+
+      - name: Report failure as issue
+        if: failure()
+        env:
+          GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+          MOD: ${{ matrix.mod }}
+        run: |
+          TITLE="[patch-break] ${MOD}"
+          {
+            echo "The weekly patch test failed for mod \`${MOD}\` against the latest Proxmox VE files."
+            echo ""
+            echo "Run: ${{ github.server_url }}/${{ github.repository }}/actions/runs/${{ github.run_id }}"
+            echo ""
+            echo "<details><summary>Test log</summary>"
+            echo ""
+            echo '```'
+            tail -n 200 test-output.log 2>/dev/null || echo "(no log captured)"
+            echo '```'
+            echo "</details>"
+          } > issue-body.md
+
+          # Ensure the label exists (no-op if it already does).
+          gh label create patch-break --color B60205 \
+            --description "pve-mod patch failed against upstream Proxmox" 2>/dev/null || true
+
+          EXISTING=$(gh issue list --state open --label patch-break \
+            --search "$TITLE in:title" --json number,title \
+            --jq ".[] | select(.title==\"$TITLE\") | .number" | head -n1)
+
+          if [[ -n "$EXISTING" ]]; then
+            gh issue comment "$EXISTING" --body-file issue-body.md
+            echo "Commented on existing issue #$EXISTING"
+          else
+            gh issue create --title "$TITLE" --label patch-break --body-file issue-body.md
+            echo "Opened new issue for mod $MOD"
+          fi
diff --git a/src/Scripts/test/fetch-proxmox-files.sh b/src/Scripts/test/fetch-proxmox-files.sh
new file mode 100644
index 0000000..282cfa7
--- /dev/null
+++ b/src/Scripts/test/fetch-proxmox-files.sh
@@ -0,0 +1,55 @@
+#!/usr/bin/env bash
+# src/Scripts/test/fetch-proxmox-files.sh
+#
+# Downloads the upstream Proxmox VE files that pve-mod patches and installs them
+# at their real system paths, so the patch engine can be exercised on a plain
+# (non-Proxmox) CI runner.
+#
+# Pulls pve-manager and proxmox-widget-toolkit from the Proxmox no-subscription
+# repository (default: PVE 9 / Debian trixie) and extracts the target files.
+#
+# CI-only helper. The repo is added with [trusted=yes]: we are only fetching
+# public, unmodified UI files to patch against, not installing Proxmox, so
+# managing the signing key would add nothing.
+
+set -euo pipefail
+
+SUITE="${PVE_SUITE:-trixie}"
+WORKDIR="$(mktemp -d)"
+trap 'rm -rf "$WORKDIR"' EXIT
+
+# Files provided by the two packages, relative to the filesystem root. These are
+# exactly the paths the .patch files (and the nag_screen post-apply hook) touch.
+FILES=(
+    usr/share/perl5/PVE/API2/Nodes.pm
+    usr/share/pve-manager/js/pvemanagerlib.js
+    usr/share/javascript/proxmox-widget-toolkit/proxmoxlib.js
+    usr/share/javascript/proxmox-widget-toolkit/proxmoxlib.min.js
+)
+
+echo "[fetch] Configuring Proxmox no-subscription repo ($SUITE)..."
+echo "deb [trusted=yes] http://download.proxmox.com/debian/pve $SUITE pve-no-subscription" \
+    | sudo tee /etc/apt/sources.list.d/pve-test.list >/dev/null
+sudo apt-get update -qq
+
+echo "[fetch] Downloading pve-manager and proxmox-widget-toolkit..."
+cd "$WORKDIR"
+apt-get download pve-manager proxmox-widget-toolkit
+
+for deb in *.deb; do
+    echo "[fetch] Extracting $deb"
+    dpkg-deb -x "$deb" extract
+done
+
+for rel in "${FILES[@]}"; do
+    src="extract/$rel"
+    dst="/$rel"
+    if [[ ! -f "$src" ]]; then
+        echo "[fetch] ERROR: expected file not found in packages: $rel" >&2
+        exit 1
+    fi
+    sudo install -Dm644 "$src" "$dst"
+    echo "[fetch] Installed $dst"
+done
+
+echo "[fetch] Done."
diff --git a/src/Scripts/test/test-mods.sh b/src/Scripts/test/test-mods.sh
new file mode 100644
index 0000000..86d3bf1
--- /dev/null
+++ b/src/Scripts/test/test-mods.sh
@@ -0,0 +1,206 @@
+#!/usr/bin/env bash
+# src/Scripts/test/test-mods.sh
+#
+# Exercises pve-mod's patch engine against the installed Proxmox files.
+#
+# Usage: test-mods.sh <mod> | all
+#
+# Mods are auto-discovered from the [modules] section of the main config, so
+# adding a new mod (a new [modules] key plus a patches/<mod>/ directory) is
+# picked up automatically - no edits to this script are required.
+#
+# For each target mod it:
+#   1. enables only that mod in the main config
+#   2. turns on every conditional flag referenced by the mod's patches.list,
+#      so all of the mod's patches are exercised (e.g. node_info's gpu_history)
+#   3. runs apply-patches.sh and asserts it exits 0
+#   4. runs revert-patches.sh and asserts it reports no unclean reversions
+#   5. restores the pristine Proxmox files before moving to the next mod
+#
+# Failure detection relies on the apply exit code: the patch engine performs an
+# atomic preflight dry-run and exits non-zero if any mod cannot apply cleanly.
+#
+# Must run as root (it edits /etc/pve-mod and the patched system files).
+
+set -u
+
+MAIN_CONF="${PVE_MOD_MAIN_CONF:-/etc/pve-mod/pve-mod.conf}"
+CONFD_DIR="${PVE_MOD_CONFD_DIR:-/etc/pve-mod/conf.d}"
+PATCHES_DIR="${PVE_MOD_PATCHES_DIR:-/usr/lib/pve-mod/patches}"
+APPLY="${PVE_MOD_APPLY:-/usr/lib/pve-mod/apply-patches.sh}"
+REVERT="${PVE_MOD_REVERT:-/usr/lib/pve-mod/revert-patches.sh}"
+
+# Proxmox files touched by the patches; snapshotted before and restored after
+# each mod so every mod is tested from a pristine baseline.
+PROXMOX_FILES=(
+    /usr/share/perl5/PVE/API2/Nodes.pm
+    /usr/share/pve-manager/js/pvemanagerlib.js
+    /usr/share/javascript/proxmox-widget-toolkit/proxmoxlib.js
+    /usr/share/javascript/proxmox-widget-toolkit/proxmoxlib.min.js
+)
+
+SNAP_DIR="$(mktemp -d)"
+trap 'rm -rf "$SNAP_DIR"' EXIT
+
+info() { echo "[test] $*"; }
+warn() { echo "[test] WARNING: $*" >&2; }
+
+# List the keys of the [modules] section in the main config, one per line.
+list_modules() {
+    [[ -f "$MAIN_CONF" ]] || return 0
+    awk -F= '
+        /^\[/ { in_sec = ($0 == "[modules]") }
+        in_sec && /^[^#=]+=/ {
+            gsub(/^[[:space:]]+|[[:space:]]+$/, "", $1)
+            print $1
+        }
+    ' "$MAIN_CONF"
+}
+
+# set_conf <file> <section> <key> <value>: set an existing key within a section.
+set_conf() {
+    local file="$1" section="$2" key="$3" value="$4"
+    [[ -f "$file" ]] || { warn "config not found: $file"; return 1; }
+    awk -v sec="[$section]" -v k="$key" -v v="$value" '
+        /^\[/ { in_sec = ($0 == sec) }
+        {
+            if (in_sec && $0 ~ "^[[:space:]]*"k"[[:space:]]*=") {
+                print k"="v
+            } else {
+                print
+            }
+        }
+    ' "$file" > "$file.tmp" && mv "$file.tmp" "$file"
+}
+
+# Disable every discovered mod in the main config.
+disable_all_modules() {
+    local m
+    for m in $(list_modules); do
+        set_conf "$MAIN_CONF" modules "$m" 0
+    done
+}
+
+# Turn on every conditional flag a mod's patches.list references, so all of its
+# patches become active. Conditions look like: <patch-file> section.key=value
+enable_conditions() {
+    local mod="$1"
+    local manifest="$PATCHES_DIR/$mod/patches.list"
+    local mod_conf="$CONFD_DIR/$mod.conf"
+    [[ -f "$manifest" ]] || return 0
+    local line cond local_key want sect ckey
+    while IFS= read -r line; do
+        line="${line%%#*}"
+        line="$(echo "$line" | sed -E 's/^[[:space:]]+|[[:space:]]+$//g')"
+        [[ -z "$line" ]] && continue
+        # Skip lines without a condition (no whitespace after the patch name).
+        [[ "$line" == *[[:space:]]* ]] || continue
+        cond="$(echo "${line#*[[:space:]]}" | sed -E 's/^[[:space:]]+//')"
+        [[ "$cond" == *=* ]] || continue
+        local_key="${cond%%=*}"
+        want="${cond#*=}"
+        sect="${local_key%%.*}"
+        ckey="${local_key#*.}"
+        set_conf "$mod_conf" "$sect" "$ckey" "$want" \
+            && info "  enabled condition $local_key=$want in $(basename "$mod_conf")"
+    done < "$manifest"
+}
+
+snapshot_files() {
+    rm -rf "$SNAP_DIR"/*; mkdir -p "$SNAP_DIR"
+    local i=0 f
+    for f in "${PROXMOX_FILES[@]}"; do
+        if [[ -e "$f" || -L "$f" ]]; then
+            cp -a "$f" "$SNAP_DIR/$i"
+        fi
+        i=$((i+1))
+    done
+}
+
+restore_files() {
+    local i=0 f
+    for f in "${PROXMOX_FILES[@]}"; do
+        if [[ -e "$SNAP_DIR/$i" || -L "$SNAP_DIR/$i" ]]; then
+            rm -f "$f"
+            cp -a "$SNAP_DIR/$i" "$f"
+        fi
+        i=$((i+1))
+    done
+}
+
+# Test a single mod end to end. Returns 0 on success, 1 on failure.
+test_one_mod() {
+    local mod="$1"
+    echo "::group::Testing mod: $mod"
+    local ok=0
+
+    if [[ ! -f "$PATCHES_DIR/$mod/patches.list" ]]; then
+        warn "no patch manifest for mod '$mod' ($PATCHES_DIR/$mod/patches.list)"
+        echo "::endgroup::"
+        return 1
+    fi
+
+    disable_all_modules
+    set_conf "$MAIN_CONF" modules "$mod" 1
+    enable_conditions "$mod"
+    snapshot_files
+
+    info "Applying patches for '$mod'..."
+    local apply_log apply_rc
+    apply_log="$("$APPLY" 2>&1)"; apply_rc=$?
+    echo "$apply_log"
+    if [[ $apply_rc -ne 0 ]]; then
+        warn "apply-patches.sh failed for mod '$mod' (exit $apply_rc)"
+        ok=1
+    fi
+
+    if [[ $ok -eq 0 ]]; then
+        info "Reverting patches for '$mod'..."
+        local revert_log
+        revert_log="$("$REVERT" 2>&1)"
+        echo "$revert_log"
+        if echo "$revert_log" | grep -qE "could not be reverted cleanly|reported an error"; then
+            warn "revert-patches.sh reported an unclean revert for mod '$mod'"
+            ok=1
+        fi
+    fi
+
+    restore_files
+
+    if [[ $ok -eq 0 ]]; then
+        info "PASS: $mod"
+    else
+        warn "FAIL: $mod"
+    fi
+    echo "::endgroup::"
+    return $ok
+}
+
+# ── main ──────────────────────────────────────────────────────────────────────
+[[ $# -eq 1 ]] || { echo "Usage: $0 <mod>|all" >&2; exit 2; }
+
+if ! command -v patch >/dev/null 2>&1; then
+    warn "'patch' command not found; install the 'patch' package."
+    exit 1
+fi
+
+targets=()
+if [[ "$1" == "all" ]]; then
+    mapfile -t targets < <(list_modules)
+    [[ ${#targets[@]} -gt 0 ]] || { warn "no mods found in [modules] of $MAIN_CONF"; exit 1; }
+else
+    targets=("$1")
+fi
+
+failed=()
+for mod in "${targets[@]}"; do
+    test_one_mod "$mod" || failed+=("$mod")
+done
+
+echo ""
+if [[ ${#failed[@]} -gt 0 ]]; then
+    warn "Failed mods: ${failed[*]}"
+    exit 1
+fi
+info "All tested mods passed: ${targets[*]}"
+exit 0