feat(test): test on 32-bit systems

.github/workflows/tox.yaml

@@ -22,36 +22,75 @@ concurrency:
 
 jobs:
   test:
-    name: Test (${{ matrix.jobtype }}, ${{ matrix.python-version}}, ${{ matrix.os }})
+    name: Test (${{ matrix.jobtype }}, ${{ matrix.python-version}}, ${{ matrix.os }}, ${{ matrix.architecture }})
     runs-on: ${{ matrix.os }}
     strategy:
       fail-fast: false
       matrix:
         os: [ubuntu-latest, macos-latest, windows-latest]
         python-version: ["3.9", "3.10", "3.11", "3.12", "3.13", "3.13t", "3.14", "3.14t"]
         jobtype: [core, ens, integration-goethereum, integration-ethtester, lint, wheel]
+        architecture: [x64, x86]
+        exclude:
+          # Exclude x86 (32-bit) builds for macos, which doesn't support 32-bit at all
+          - os: macos-latest
+            architecture: x86
     env:
       TOXENV: py${{ matrix.python-version }}-${{ matrix.jobtype }}
       TOX_RECREATE_FLAG: ${{ github.event_name == 'schedule' && '-r' || '' }}
+      IS_UBUNTU_32BIT: ${{ matrix.os == 'ubuntu-latest' && matrix.architecture == 'x86' }}
     steps:
       - uses: actions/checkout@v5
 
+      # Use i386/python Docker for all 32-bit Ubuntu jobs (TODO cache some of this)
+      - name: Run job in 32-bit Ubuntu Docker container
+        if: ${{ env.IS_UBUNTU_32BIT == 'true' }}
+        uses: addnab/docker-run-action@v3
+        with:
+          image: i386/python:${{ matrix.python-version }}
+          shell: bash
+          options: -v ${{ github.workspace }}:/workspace -w /workspace
+          run: |
+            python -m pip install --upgrade pip
+            python -m pip install tox
+            python -m tox -e ${{ env.TOXENV }} ${{ env.TOX_RECREATE_FLAG }}
+        # There are no prebuilt 32-bit freethreaded Python containers at the time of this commit, but
+        # we will keep these runners so they will activate on their own whenever such containers exist
+        continue-on-error: ${{ matrix.python-version == '3.13t' || matrix.python-version == '3.14t' }}
+
+      # No architecture specified for MacOS
+      - name: Set up Python (macos)
+        if: ${{ matrix.os == 'macos-latest' }}
+        uses: actions/setup-python@v5
+        with:
+          python-version: ${{ matrix.python-version }}
+          cache: pip
+          cache-dependency-path: |
+            setup.py
+            pyproject.toml
+            tox.ini
+
+      # All other builds (64-bit Linux, 32-bit and 64-bit Windows)
       - name: Set up Python
-        uses: actions/setup-python@v6
+        if: ${{ matrix.os != 'macos-latest' && env.IS_UBUNTU_32BIT != 'true' }}
+        uses: actions/setup-python@v5
         with:
           python-version: ${{ matrix.python-version }}
+          architecture: ${{ matrix.architecture }}
           cache: pip
           cache-dependency-path: |
             pyproject.toml
             setup.py
             tox.ini
 
       - name: Upgrade pip and install tox
+        if: ${{ env.IS_UBUNTU_32BIT != 'true' }}
         run: |
           python -m pip install --upgrade pip
           python -m pip install tox
 
       - name: Cache tox environment and hypothesis examples
+        if: ${{ env.IS_UBUNTU_32BIT != 'true' }}
         uses: actions/cache@v4
         with:
           path: |
@@ -61,4 +100,5 @@ jobs:
           save-always: ${{ env.TOX_RECREATE_FLAG == '-r' }}
 
       - name: Run tox
+        if: ${{ env.IS_UBUNTU_32BIT != 'true' }}
         run: python -m tox run  ${{ env.TOX_RECREATE_FLAG }}