diff --git a/.github/workflows/tests.yml b/.github/workflows/tests.yml
index 4b17f407..e55fd0b9 100644
--- a/.github/workflows/tests.yml
+++ b/.github/workflows/tests.yml
@@ -14,8 +14,9 @@ jobs:
         include:
           - { python: "3.12", os: "ubuntu-latest", session: "pre-commit" }
           # - { python: "3.12", os: "ubuntu-latest", session: "mypy" }
-          - { python: "3.11", os: "ubuntu-latest", session: "tests" }
           - { python: "3.10", os: "ubuntu-latest", session: "tests" }
+          - { python: "3.11", os: "ubuntu-latest", session: "tests" }
+          - { python: "3.12", os: "ubuntu-latest", session: "tests" }
           - { python: "3.12", os: "windows-latest", session: "tests" }
           - { python: "3.12", os: "macos-latest", session: "tests" }
           - { python: "3.12", os: "ubuntu-latest", session: "xdoctest" }
@@ -26,6 +27,18 @@ jobs:
       PRE_COMMIT_COLOR: "always"
 
     steps:
+      ###############################
+      # Work around pipx issue #1331 with absolute path to constraint.txt
+      # https://github.com/pypa/pipx/issues/1331#issuecomment-2043163012
+      - name: Set PIP_ARGS on Windows
+        run: echo "PIP_ARGS=--constraint=$env:GITHUB_WORKSPACE/.github/workflows/constraints.txt" | Out-File -FilePath $env:GITHUB_ENV -Append
+        if: runner.os == 'Windows'
+
+      - name: Set PIP_ARGS on not-Windows
+        run: echo "PIP_ARGS=--constraint=$GITHUB_WORKSPACE/.github/workflows/constraints.txt" >> "$GITHUB_ENV"
+        if: runner.os != 'Windows'
+      ###############################
+
       - name: Check out the repository
         uses: actions/checkout@v4
 
@@ -36,7 +49,7 @@ jobs:
 
       - name: Upgrade pip
         run: |
-          pip install --constraint=.github/workflows/constraints.txt pip
+          pip install ${{ env.PIP_ARGS }} pip
           pip --version
 
       - name: Upgrade pip in virtual environments
@@ -50,13 +63,13 @@ jobs:
 
       - name: Install Poetry
         run: |
-          pipx install --pip-args=--constraint=.github/workflows/constraints.txt poetry
+          pipx install --pip-args=${{ env.PIP_ARGS }} poetry
           poetry --version
 
       - name: Install Nox
         run: |
-          pipx install --pip-args=--constraint=.github/workflows/constraints.txt nox
-          pipx inject --pip-args=--constraint=.github/workflows/constraints.txt nox nox-poetry
+          pipx install --pip-args=${{ env.PIP_ARGS }} nox
+          pipx inject --pip-args=${{ env.PIP_ARGS }} nox nox-poetry
           nox --version
 
       - name: Compute pre-commit cache key
@@ -115,18 +128,18 @@ jobs:
 
       - name: Upgrade pip
         run: |
-          pip install --constraint=.github/workflows/constraints.txt pip
+          pip install ${{ env.PIP_ARGS }} pip
           pip --version
 
       - name: Install Poetry
         run: |
-          pipx install --pip-args=--constraint=.github/workflows/constraints.txt poetry
+          pipx install --pip-args=${{ env.PIP_ARGS }} poetry
           poetry --version
 
       - name: Install Nox
         run: |
-          pipx install --pip-args=--constraint=.github/workflows/constraints.txt nox
-          pipx inject --pip-args=--constraint=.github/workflows/constraints.txt nox nox-poetry
+          pipx install --pip-args=${{ env.PIP_ARGS }} nox
+          pipx inject --pip-args=${{ env.PIP_ARGS }} nox nox-poetry
           nox --version
 
       - name: Download coverage data