test: isolate Nix store/cache per distro to fix cross-distro manifest conflicts

- Replace shared Nix volumes with distro-specific volumes
  (pkgmgr_nix_store_<distro>, pkgmgr_nix_cache_<distro>)
- Prevent incompatible profile manifest versions between Ubuntu and Debian
- Update all test scripts (unit, integration, container, e2e)
- Remove unused global Nix volume variables from Makefile
- Improve consistency of test-e2e.sh formatting and environment handling
- Add Git safe.directory configuration for mounted /src to avoid ownership warnings

Makefile

@@ -2,12 +2,6 @@
         test build build-no-cache test-unit test-e2e test-integration \
         test-container
 
-# ------------------------------------------------------------
-# Local Nix cache directories in the repo
-# ------------------------------------------------------------
-NIX_STORE_VOLUME := pkgmgr_nix_store
-NIX_CACHE_VOLUME := pkgmgr_nix_cache
-
 # ------------------------------------------------------------
 # Distro list and base images
 # (kept for documentation/reference; actual build logic is in scripts/build)

scripts/test/test-container.sh

@@ -19,9 +19,9 @@ for distro in $DISTROS; do
     # Run the command and capture the output
     if OUTPUT=$(docker run --rm \
             -e PKGMGR_DEV=1 \
-            -v pkgmgr_nix_store:/nix \
+            -v pkgmgr_nix_store_${distro}:/nix \
             -v "$(pwd):/src" \
-            -v "pkgmgr_nix_cache:/root/.cache/nix" \
+            -v "pkgmgr_nix_cache_${distro}:/root/.cache/nix" \
             "$IMAGE" 2>&1); then
         echo "$OUTPUT"
         echo

scripts/test/test-e2e.sh

@@ -10,43 +10,46 @@ for distro in $DISTROS; do
 
   docker run --rm \
     -v "$(pwd):/src" \
-    -v pkgmgr_nix_store:/nix \
-    -v "pkgmgr_nix_cache:/root/.cache/nix" \
+    -v pkgmgr_nix_store_${distro}:/nix \
+    -v "pkgmgr_nix_cache_${distro}:/root/.cache/nix" \
     -e PKGMGR_DEV=1 \
     -e TEST_PATTERN="${TEST_PATTERN}" \
     --workdir /src \
     --entrypoint bash \
     "package-manager-test-$distro" \
     -c '
-      set -e;
+      set -e
 
+      # Load distro info
       if [ -f /etc/os-release ]; then
-        . /etc/os-release;
-      fi;
+        . /etc/os-release
+      fi
 
-      echo "Running tests inside distro: $ID";
+      echo "Running tests inside distro: $ID"
 
-      # Try to load nix environment
+      # Load nix environment if available
       if [ -f "/nix/var/nix/profiles/default/etc/profile.d/nix-daemon.sh" ]; then
-        . "/nix/var/nix/profiles/default/etc/profile.d/nix-daemon.sh";
+        . "/nix/var/nix/profiles/default/etc/profile.d/nix-daemon.sh"
       fi
 
       if [ -f "$HOME/.nix-profile/etc/profile.d/nix.sh" ]; then
-        . "$HOME/.nix-profile/etc/profile.d/nix.sh";
+        . "$HOME/.nix-profile/etc/profile.d/nix.sh"
       fi
 
-      PATH="/nix/var/nix/profiles/default/bin:$HOME/.nix-profile/bin:$PATH";
+      PATH="/nix/var/nix/profiles/default/bin:$HOME/.nix-profile/bin:$PATH"
 
       command -v nix >/dev/null || {
-        echo "ERROR: nix not found.";
-        exit 1;
+        echo "ERROR: nix not found."
+        exit 1
       }
 
-      git config --global --add safe.directory /src || true;
+      # Mark the mounted repository as safe to avoid Git ownership errors
+      git config --global --add safe.directory /src || true
 
+      # Run the E2E tests inside the Nix development shell
       nix develop .#default --no-write-lock-file -c \
         python3 -m unittest discover \
           -s /src/tests/e2e \
-          -p "$TEST_PATTERN";
+          -p "$TEST_PATTERN"
     '
 done

scripts/test/test-integration.sh

@@ -7,8 +7,8 @@ echo "============================================================"
 
 docker run --rm \
   -v "$(pwd):/src" \
-  -v pkgmgr_nix_store:/nix \
-  -v "pkgmgr_nix_cache:/root/.cache/nix" \
+  -v pkgmgr_nix_store_${distro}:/nix \
+  -v "pkgmgr_nix_cache_${distro}:/root/.cache/nix" \
   --workdir /src \
   -e PKGMGR_DEV=1 \
   -e TEST_PATTERN="${TEST_PATTERN}" \

scripts/test/test-unit.sh

@@ -7,8 +7,8 @@ echo "============================================================"
 
 docker run --rm \
   -v "$(pwd):/src" \
-  -v "pkgmgr_nix_cache:/root/.cache/nix" \
-  -v pkgmgr_nix_store:/nix \
+  -v "pkgmgr_nix_cache_${distro}:/root/.cache/nix" \
+  -v pkgmgr_nix_store_${distro}:/nix \
   --workdir /src \
   -e PKGMGR_DEV=1 \
   -e TEST_PATTERN="${TEST_PATTERN}" \