diff --git a/.github/actions/test-oxcaml/action.yml b/.github/actions/test-oxcaml/action.yml
new file mode 100644
index 000000000..2dada6c91
--- /dev/null
+++ b/.github/actions/test-oxcaml/action.yml
@@ -0,0 +1,88 @@
+---
+name: Setup OxCaml with a predefined set of opam packages
+inputs:
+  ocaml-compiler:
+    description: The OCaml compiler switch to install
+    required: true
+
+  opam-disable-sandboxing:
+    description: Disable the opam sandboxing feature.
+    required: false
+    default: "false"
+
+runs:
+  using: "composite"
+  steps:
+    - name: Install required packages on Linux
+      shell: sh
+      run: |
+        set -e
+        if [ "$(uname)" = "Linux" ]; then
+          if [ -f /etc/os-release ]; then
+            . /etc/os-release
+            echo "Detected Linux distro: $ID"
+            case "$ID" in
+              ubuntu|debian)
+                apt-get update
+                DEBIAN_FRONTEND=noninteractive apt-get install -y \
+                    build-essential curl git rsync sudo unzip nano
+                ;;
+              arch)
+                pacman -Sy --noconfirm make gcc patch tar ca-certificates git \
+                    rsync curl sudo bash nano coreutils xz ncurses diffutils \
+                    unzip
+                ;;
+              *)
+                echo "Unsupported Linux distro: $ID"
+                exit 1
+                ;;
+            esac
+          else
+            echo "Missing /etc/os-release on Linux?"
+            exit 1
+          fi
+        else
+          # Installing autoconf beforehand prevents recompilation of the
+          # compiler when restoring from the cache
+          brew install autoconf
+        fi
+
+    - name: Get hash of the ocaml-variant opam file
+      id: hash-opam-file
+      shell: bash
+      env:
+        OCAML_COMPILER: ${{ inputs.ocaml-compiler }}
+      run: |
+        set -e
+        OPAM_FILE="packages/ocaml-variants/${OCAML_COMPILER}/opam"
+
+        if command -v sha256sum >/dev/null 2>&1; then
+          COMMAND="sha256sum"
+        elif command -v shasum >/dev/null 2>&1; then
+          COMMAND="shasum -a 256"
+        else
+          echo "ERROR: Neither sha256sum nor shasum is available." >&2
+          exit 1
+        fi
+
+        HASH=$($COMMAND "$OPAM_FILE" | awk '{print $1}')
+        echo "hash=${HASH}" >> "$GITHUB_OUTPUT"
+
+    - uses: ocaml/setup-ocaml@v3.3.5
+      with:
+        cache-prefix: ${{ steps.hash-opam-file.outputs.hash }}
+        ocaml-compiler: ${{ inputs.ocaml-compiler }}
+        opam-pin: false
+        opam-disable-sandboxing: ${{ inputs.opam-disable-sandboxing }}
+        opam-repositories: |
+          oxcaml: .
+          default: https://github.com/ocaml/opam-repository.git
+
+    - name: Install common opam packages
+      shell: bash
+      run: |
+        opam --version
+        opam repository list
+        opam list
+        opam install ocamlformat merlin ocaml-lsp-server utop parallel core_unix
+        opam list
diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index 95a4e67ca..8bca1ed14 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -8,41 +8,47 @@ on:
   schedule:
     - cron: "30 0 * * *"
 
+# For info on the OS versions, architecture, etc., see
+# https://docs.github.com/en/actions/using-github-hosted-runners/using-github-hosted-runners/about-github-hosted-runners#standard-github-hosted-runners-for-public-repositories
+
 jobs:
-  test-setup:
-    env:
-      OCAML_VARIANT: ocaml-variants.5.2.0+ox
+  test-linux:
     strategy:
       fail-fast: false
       matrix:
-        # For info on the OS versions, architecture, etc., see
-        # https://docs.github.com/en/actions/using-github-hosted-runners/using-github-hosted-runners/about-github-hosted-runners#standard-github-hosted-runners-for-public-repositories
-        os: [ubuntu-latest, ubuntu-24.04-arm, macos-13, macos-latest]
+        image: [ubuntu:24.04, debian:bookworm]
+        os: [ubuntu-latest, ubuntu-24.04-arm]
+        include:
+          - image: archlinux:latest
+            os: ubuntu-latest
     runs-on: ${{ matrix.os }}
+    container:
+      image: ${{ matrix.image }}
     steps:
+      - name: Check OS info
+        run: |
+          uname -a
+
       - name: Checkout the repository
         uses: actions/checkout@v4
 
-      - name: Get hash of the ocaml-variant opam file
-        id: hash-opam-file
-        run: |
-          HASH=$(shasum -a 256 packages/ocaml-variants/${OCAML_VARIANT}/opam | awk '{print $1}')
-          echo "hash=${HASH}" >> "$GITHUB_OUTPUT"
-
-      - uses: ocaml/setup-ocaml@v3
+      - name: Run Test OxCaml action
+        uses: ./.github/actions/test-oxcaml
         with:
-          # Invalidate cache when opam file for the ocaml-variant changes
-          cache-prefix: ${{ steps.hash-opam-file.outputs.hash }}
-          ocaml-compiler: ${{ env.OCAML_VARIANT }}
-          opam-pin: false
-          opam-repositories: |
-            oxcaml: .
-            default: https://github.com/ocaml/opam-repository.git
+          ocaml-compiler: ocaml-variants.5.2.0+ox
+          opam-disable-sandboxing: true
 
-      - name: opam install packages
-        run: |
-          opam --version
-          opam repository list
-          opam list
-          opam install ocamlformat merlin ocaml-lsp-server utop parallel core_unix
-          opam list
+  test-macos:
+    strategy:
+      fail-fast: false
+      matrix:
+        os: [macos-13, macos-latest]
+    runs-on: ${{ matrix.os }}
+    steps:
+      - name: Checkout the repository
+        uses: actions/checkout@v4
+
+      - name: Run Test OxCaml action
+        uses: ./.github/actions/test-oxcaml
+        with:
+          ocaml-compiler: ocaml-variants.5.2.0+ox