diff --git a/.github/workflows/build_docs.yml b/.github/workflows/build_docs.yml
index 8745acd..8f2ee01 100644
--- a/.github/workflows/build_docs.yml
+++ b/.github/workflows/build_docs.yml
@@ -46,11 +46,14 @@ jobs:
       # This action sets the current path to the root of your github repo
       - uses: actions/checkout@v7
 
-      - name: Update pip
-        run: python3 -m pip install  --upgrade pip setuptools
+      - name: Update pip and extra deps
+        run: |
+           python3 -m pip install  --upgrade pip setuptools
+           python3 -m pip install --no-binary=h5py h5py
+           python3 -m pip install . --group docs
 
       - name: Install dependencies
-        run: python3 -m pip install --no-binary=h5py  -e ".[docs]"
+        run: python3 -m pip install -e . --no-build-isolation
 
       - name: Build docs
         run: jupyter book build .
diff --git a/.github/workflows/check_formatting.yml b/.github/workflows/check_formatting.yml
index afe2700..96183fc 100644
--- a/.github/workflows/check_formatting.yml
+++ b/.github/workflows/check_formatting.yml
@@ -43,11 +43,13 @@ jobs:
     steps:
       - uses: actions/checkout@v7
 
-      - name: Update pip
-        run: python3 -m pip install  --upgrade pip setuptools
+      - name: Update pip and install build deps
+        run: |
+          python3 -m pip install  --upgrade pip setuptools
+          python3 -m pip install . --group dev --no-build-isolation
 
       - name: Install code
-        run: python3 -m pip install  .[dev]
+        run: python3 -m pip install  . --no-build-isolation
 
       - name: Check code formatting with ruff
         run: |
diff --git a/.github/workflows/test_dolfinx_versions.yml b/.github/workflows/test_dolfinx_versions.yml
index 56441dd..c9233ab 100644
--- a/.github/workflows/test_dolfinx_versions.yml
+++ b/.github/workflows/test_dolfinx_versions.yml
@@ -31,4 +31,4 @@ jobs:
     # Call the reusable workflow
     uses: ./.github/workflows/test_workflow.yml
     with:
-      dolfinx_tag: ${{ matrix.tag }}
+      tag: ${{ matrix.tag }}
diff --git a/.github/workflows/test_package_openmpi.yml b/.github/workflows/test_package_openmpi.yml
deleted file mode 100644
index 7c98a9a..0000000
--- a/.github/workflows/test_package_openmpi.yml
+++ /dev/null
@@ -1,88 +0,0 @@
-name: Test package with different mpi compilers
-
-on:
-  push:
-    branches:
-      - main
-  pull_request:
-    branches:
-      - main
-
-  workflow_call:
-  workflow_dispatch:
-  schedule:
-    - cron: "0 8 * * *"
-
-jobs:
-  create-datasets:
-    uses: ./.github/workflows/create_legacy_data.yml
-    with:
-      artifact_name: "legacy_ompi"
-
-  create-legacy-datasets:
-    uses: ./.github/workflows/create_legacy_checkpoint.yml
-    with:
-      artifact_name: "legacy_checkpoint_ompi"
-
-  test-code:
-    runs-on: ubuntu-latest
-    needs: [create-datasets, create-legacy-datasets]
-    container: ${{ matrix.container }}
-    env:
-      DEB_PYTHON_INSTALL_LAYOUT: deb_system
-      PETSC_ARCH: "linux-gnu-real64-32"
-      OMPI_ALLOW_RUN_AS_ROOT: 1
-      OMPI_ALLOW_RUN_AS_ROOT_CONFIRM: 1
-      PRTE_MCA_rmaps_default_mapping_policy: :oversubscribe
-      working-directory: ./src
-      PIP_NO_BINARY: h5py
-
-    strategy:
-      matrix:
-        adios2: ["v2.11.0", "v2.12.1", "default"]
-        container:
-          - ghcr.io/fenics/test-env:current-openmpi
-          - ghcr.io/fenics/test-env:current-mpich
-    steps:
-      - uses: actions/checkout@v7
-
-      - name: Update pip
-        run: python3 -m pip install  --upgrade pip
-
-      - name: Install build requirements
-        run: python3 -m pip install  -r build-requirements.txt
-
-      - name: Install DOLFINx
-        uses: jorgensd/actions/install-dolfinx@v0.4
-        with:
-          adios2: ${{ matrix.adios2 }}
-          petsc_arch: ${{ env.PETSC_ARCH }}
-          dolfinx: main
-          basix: main
-          ufl: main
-          ffcx: main
-          working-directory: ${{ env.working-directory}}
-
-      - name: Download legacy data
-        uses: actions/download-artifact@v8
-        with:
-          name: legacy_ompi
-          path: ./legacy
-
-      - name: Download legacy data
-        uses: actions/download-artifact@v8
-        with:
-          name: legacy_checkpoint_ompi
-          path: ./legacy_checkpoint
-
-      - name: Install package
-        run: |
-          HDF5_MPI=ON HDF5_PKGCONFIG_NAME="hdf5" python3 -m pip install h5py  --no-build-isolation --no-binary=h5py
-          python3 -m pip install  .[test]
-      - name: Run tests
-        run: |
-          coverage run --rcfile=.coveragerc -m mpi4py -m pytest -xvs ./tests/
-
-      - name: Run tests in parallel
-        run: |
-          mpirun -n 2 coverage run --rcfile=.coveragerc -m mpi4py -m pytest -xvs ./tests/
diff --git a/.github/workflows/test_redhat.yml b/.github/workflows/test_redhat.yml
deleted file mode 100644
index e0a8b65..0000000
--- a/.github/workflows/test_redhat.yml
+++ /dev/null
@@ -1,93 +0,0 @@
-name: Test package with redhat
-
-on:
-  # push:
-  #   branches:
-  #     - main
-  # pull_request:
-  #   branches:
-  #     - main
-
-  workflow_call:
-  workflow_dispatch:
-  # schedule:
-  #   - cron: "0 8 * * *"
-
-jobs:
-  create-datasets:
-    uses: ./.github/workflows/create_legacy_data.yml
-    with:
-      artifact_name: "legacy_ompi"
-
-  create-legacy-datasets:
-    uses: ./.github/workflows/create_legacy_checkpoint.yml
-    with:
-      artifact_name: "legacy_checkpoint_ompi"
-
-  test-code:
-    runs-on: "ubuntu-latest"
-    needs: [create-datasets, create-legacy-datasets]
-    container: docker.io/fenicsproject/test-env:current-redhat
-    env:
-      DEB_PYTHON_INSTALL_LAYOUT: deb_system
-      PETSC_ARCH: ""
-      PETSC_DIR: "/usr/local/"
-      PYTHONPATH: "/usr/local/lib/:${PYTHONPATH}"
-      working-directory: ./src
-
-    strategy:
-      matrix:
-        adios2: ["master"]
-    steps:
-      - uses: actions/checkout@v7
-
-      - name: Get pip flags based on version
-        id: python-version
-        shell: bash -el {0}
-        run: |
-          MODERN_PIP=$(python3 -c "import sys; t = sys.version_info >= (3, 11, 0); sys.stdout.write(str(t))")
-          if [ ${MODERN_PIP} == "True" ]; then
-            FLAGS="--break-system-packages"
-          else
-            FLAGS=""
-            python3 -m pip install --upgrade pip
-          fi
-          echo "PYTHON_FLAGS=${FLAGS}" >> "$GITHUB_OUTPUT"
-
-      - name: Update pip
-        run: python3 -m pip install ${{ steps.python-version.outputs.PYTHON_FLAGS}} --upgrade pip setuptools
-
-      - name: Install DOLFINx
-        uses: jorgensd/actions/install-dolfinx@v0.4
-        with:
-          adios2: ${{ matrix.adios2 }}
-          petsc_arch: ${{ env.PETSC_ARCH }}
-          petsc_dir: ${{ env.PETSC_DIR }}
-          dolfinx: main
-          basix: main
-          ufl: main
-          ffcx: main
-          working-directory: ${{ env.working-directory}}
-
-      - name: Download legacy data
-        uses: actions/download-artifact@v8
-        with:
-          name: legacy_ompi
-          path: ./legacy
-
-      - name: Download legacy data
-        uses: actions/download-artifact@v8
-        with:
-          name: legacy_checkpoint_ompi
-          path: ./legacy_checkpoint
-
-      - name: Install package
-        run: python3 -m pip install ${{ steps.python-version.outputs.PYTHON_FLAGS}} --check-build-dependencies .[test]
-
-      - name: Run tests
-        run: |
-          coverage run --rcfile=.coveragerc -m mpi4py -m pytest -xvs ./tests
-
-      - name: Run tests in parallel
-        run: |
-          mpirun -n 4 coverage run --rcfile=.coveragerc -m mpi4py -m pytest -xvs ./tests
diff --git a/.github/workflows/test_workflow.yml b/.github/workflows/test_workflow.yml
index 7849337..11e0728 100644
--- a/.github/workflows/test_workflow.yml
+++ b/.github/workflows/test_workflow.yml
@@ -1,17 +1,49 @@
-name: Test
+name: Test package
 
 on:
   workflow_call:
     inputs:
-      dolfinx_tag:
+      tag:
+        description: "Tag of DOLFINx docker image"
+        default: "nightly"
         required: true
         type: string
+  workflow_dispatch:
+    inputs:
+      tag:
+        description: "Tag of DOLFINx docker image"
+        default: "nightly"
+        required: true
+        type: string
+env:
+  DEB_PYTHON_INSTALL_LAYOUT: deb_system
+  DEFAULT_TAG: nightly
+  HDF5_MPI: "ON"
+  HDF5_INCLUDEDIR: "/usr/include/hdf5/openmpi"
+  H5PY_SETUP_REQUIRES: 0
+  OMPI_ALLOW_RUN_AS_ROOT: 1
+  OMPI_ALLOW_RUN_AS_ROOT_CONFIRM: 1
+  PRTE_MCA_rmaps_default_mapping_policy: :oversubscribe
+  CC: mpicc
+  CXX: mpicxx
 
 jobs:
+  get_image_tag:
+    runs-on: ubuntu-latest
+    outputs:
+      image: ${{ steps.docker_tag.outputs.image }}
+    steps:
+      - id: docker_tag
+        run: echo "image=${{ inputs.tag || env.DEFAULT_TAG }}" >> $GITHUB_OUTPUT
+
   test-code:
     runs-on: ubuntu-24.04
     # The container tag is now dynamic based on the input passed by the caller
-    container: ghcr.io/fenics/dolfinx/dolfinx:${{ inputs.dolfinx_tag }}
+    container: ghcr.io/fenics/test-env:current
+    needs:
+      [get_image_tag]
+    env:
+      working-directory: ./src
 
     steps:
       - uses: actions/checkout@v7
@@ -20,7 +52,8 @@ jobs:
         run: python3 -m pip install --upgrade pip
 
       - name: Install build requirements
-        run: python3 -m pip install -r build-requirements.txt
+        run: python3 -m pip install --group build --no-build-isolation
+
 
       # Note: We assume the caller workflow has already uploaded these artifacts
       - name: Download legacy mpich data
@@ -35,10 +68,38 @@ jobs:
           name: legacy_checkpoint_mpich
           path: ./legacy_checkpoint
 
+      - name: Install DOLFINx (stable)
+        if: needs.get_image_tag.outputs.image == 'stable'
+        uses: jorgensd/actions/install-dolfinx@v0.4
+        with:
+          adios2: default
+          petsc_arch: linux-gnu-real64-32
+          dolfinx: release
+          basix: release
+          ufl: release
+          ffcx: release
+          working-directory: ${{ env.working-directory}}
+
+      - name: Install DOLFINx (nightly)
+        if: needs.get_image_tag.outputs.image == 'nightly'
+        uses: jorgensd/actions/install-dolfinx@v0.4
+        with:
+          adios2: default
+          petsc_arch: linux-gnu-real64-32
+          working-directory: ${{ env.working-directory}}
+
+      - name: Configure HDF5 MPI Environment
+        run: |
+          # Evaluate architecture dynamically and write to GITHUB_ENV
+          ARCH_TRIPLET=$(gcc -print-multiarch)
+          echo "HDF5_LIBDIR=/usr/lib/${ARCH_TRIPLET}/hdf5/openmpi" >> $GITHUB_ENV
+
       - name: Install package
         run: |
-          HDF5_MPI=ON HDF5_PKGCONFIG_NAME="hdf5" python3 -m pip install h5py --no-build-isolation --no-binary=h5py
-          python3 -m pip install .[test]
+          python3 -m pip install "Cython>=3.0.11" "pkgconfig>=1.5.5"
+          python3 -m pip install h5py --no-binary=h5py --no-build-isolation
+          python3 -m pip install --group dev --group test
+          python3 -m pip install . --no-build-isolation
 
       - name: Show adios2 version
         run: python3 -c "import adios2; print(adios2.__version__)"
@@ -65,6 +126,6 @@ jobs:
       - name: Upload coverage report
         uses: actions/upload-artifact@v7
         with:
-          name: code-coverage-report-${{ inputs.dolfinx_tag }}
+          name: code-coverage-report-${{ inputs.tag }}
           path: htmlcov
           if-no-files-found: error
diff --git a/build-requirements.txt b/build-requirements.txt
deleted file mode 100644
index a58cd3b..0000000
--- a/build-requirements.txt
+++ /dev/null
@@ -1,5 +0,0 @@
-scikit-build-core[pyproject]>=0.11.0
-nanobind>=1.3.2
-setuptools>=77.0.3
-packaging>=24.2
-pkgconfig
diff --git a/docs/testing.md b/docs/testing.md
index 7751c05..e7cbe20 100644
--- a/docs/testing.md
+++ b/docs/testing.md
@@ -21,7 +21,8 @@ Install the library with the optional `test` dependencies to ensure you have
 packages like `pytest`, `coverage`, and `ipyparallel`
 
 ```bash
-python3 -m pip install ".[test]"
+python3 -m pip install . --group test --no-build-isolation
+python3 -m pip install -e . --no-build-isolation
 ```
 
 ### Running Tests
diff --git a/pyproject.toml b/pyproject.toml
index ccb8852..fb1bed6 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -1,5 +1,13 @@
-[build-system] # Require setuptool version due to https://github.com/pypa/setuptools/issues/2938
-requires = ["setuptools>=61.0.0", "wheel"]
+[build-system]
+requires = [
+    "setuptools>=77.0.3",
+    "wheel",
+    "scikit-build-core[pyproject]>=0.11.0",
+    "nanobind>=1.3.2,<2.15",  # Temporary cap on nanobind for stable dolfinx
+    "packaging>=24.2",
+    "pkgconfig"
+]
+build-backend = "setuptools.build_meta"
 
 [project]
 name = "io4dolfinx"
@@ -11,9 +19,24 @@ authors = [
 ]
 license = { file = "LICENSE" }
 readme = "README.md"
+requires-python = ">=3.12"
 dependencies = ["fenics-dolfinx>=0.10.0", "packaging"]
 
 [project.optional-dependencies]
+h5py = ["h5py"]
+pyvista = ["pyvista"]
+xdmf = ["h5py"]
+exodus = ["netcdf4"]
+
+[dependency-groups]
+build = [
+    "scikit-build-core[pyproject]>=0.11.0",
+    "nanobind>=1.3.2,<3.0",
+    "setuptools>=77.0.3",
+    "packaging>=24.2",
+    "pkgconfig"
+]
+
 test = [
     "pytest",
     "coverage",
@@ -22,23 +45,28 @@ test = [
     "io4dolfinx[pyvista]",
     "io4dolfinx[xdmf]"
 ]
-dev = ["pdbpp", "ipython", "mypy", "ruff"]
-h5py = ["h5py"]
-pyvista = ["pyvista"]
-xdmf = ["h5py"]
-exodus = ["netcdf4"]
+dev = [
+    "pdbpp",
+    "ipython",
+    "mypy",
+    "ruff"
+]
 docs = [
     "jupyter-book<2.0.0",
     "ipyparallel",
     "ipywidgets",
     "jupytext",
-    "ipykernel<7.0.0",     # Note: Remove once https://github.com/ipython/ipykernel/issues/1450 is in a release
+    "ipykernel",
     "sphinx-codeautolink",
     "io4dolfinx[h5py]",
     "io4dolfinx[pyvista]",
     "sphinx_external_toc<1.1.0",
 ]
-all = ["io4dolfinx[test,dev,docs]"]
+all = [
+    { include-group = "test" },
+    { include-group = "dev" },
+    { include-group = "docs" }
+]
 
 [tool.pytest.ini_options]
 addopts = ["--import-mode=importlib"]
@@ -67,7 +95,6 @@ select = [
     "I001",
 ]
 
-
 [tool.ruff.lint.isort]
 known-first-party = ["io4dolfinx"]
 known-third-party = [
@@ -91,7 +118,6 @@ section-order = [
 [tool.ruff.lint.isort.sections]
 "mpi" = ["mpi4py", "petsc4py"]
 
-
 [tool.bumpversion]
 allow_dirty = false
 commit = true
@@ -102,7 +128,6 @@ tag_name = "v{new_version}"
 tag_message = "Bump version: {current_version} → {new_version}"
 current_version = "1.3.0"
 
-
 [[tool.bumpversion.files]]
 filename = "pyproject.toml"
 search = 'version = "{current_version}"'
diff --git a/src/io4dolfinx/checkpointing.py b/src/io4dolfinx/checkpointing.py
index a128ef6..de4f8c0 100644
--- a/src/io4dolfinx/checkpointing.py
+++ b/src/io4dolfinx/checkpointing.py
@@ -6,6 +6,7 @@
 
 from __future__ import annotations
 
+import inspect
 import logging
 import typing
 from pathlib import Path
@@ -454,20 +455,21 @@ def read_mesh(
         dtype=dist_in_data.x.dtype,
     )
     domain = ufl.Mesh(element)
-    PartitionerType = Callable[
-        [MPI.Comm, int, list[dolfinx.mesh.CellType], list[npt.NDArray[np.int64]]],
-        dolfinx.cpp.graph.AdjacencyList_int32,
-    ]
-    partitioner: PartitionerType
+    # `dolfinx.mesh.PartitioningFunc` is not available in all supported
+    # versions of DOLFINx, and the accepted callback signature varies (see
+    # below), so type the callback permissively.
+    partitioner: Callable[..., dolfinx.cpp.graph.AdjacencyList_int32]
     if (partition_graph := dist_in_data.partition_graph) is not None:
-
-        def _custom_partitioner(
-            comm: MPI.Comm,
-            nparts: int,
-            cell_types: list[dolfinx.mesh.CellType],
-            local_graph: list[npt.NDArray[np.int64]],
-        ) -> dolfinx.cpp.graph.AdjacencyList_int32:
-            assert len(local_graph[0]) % (len(partition_graph.offsets) - 1) == 0
+        # The arguments DOLFINx passes to a partitioner callback have changed
+        # over time: 0.11 calls it with
+        # ``(comm, nparts, cell_types, local_graph)``, while newer versions call
+        # it with ``(comm, nparts, dual_graph, cell_weights, edge_weights,
+        # ghosting)`` (see https://github.com/FEniCS/dolfinx/pull/4403).
+        # We read the partitioning from file, so the returned graph does not
+        # depend on any of these arguments. Accept them all and stay agnostic to
+        # the calling convention rather than branching on `dolfinx.__version__`,
+        # which does not distinguish pre-releases and post-releases reliably.
+        def _custom_partitioner(*args: Any, **kwargs: Any) -> dolfinx.cpp.graph.AdjacencyList_int32:
             if hasattr(partition_graph, "_cpp_object"):
                 cpp_obj = partition_graph._cpp_object
                 assert isinstance(cpp_obj, dolfinx.cpp.graph.AdjacencyList_int32)
@@ -478,21 +480,28 @@ def _custom_partitioner(
 
         partitioner = _custom_partitioner
     else:
-        try:
-            partitioner = dolfinx.cpp.mesh.create_cell_partitioner(
-                ghost_mode, max_facet_to_cell_links=max_facet_to_cell_links
-            )
-        except TypeError:
-            partitioner = dolfinx.cpp.mesh.create_cell_partitioner(ghost_mode)  # type: ignore[call-overload]
-
-        # Should change to the commented code below when we require python
-        # minimum version to be >=3.12 see https://github.com/python/cpython/pull/116198
-        # import inspect
-        # sig = inspect.signature(dolfinx.mesh.create_cell_partitioner)
-        # part_kwargs = {}
-        # if "max_facet_to_cell_links" in list(sig.parameters.keys()):
-        #     part_kwargs["max_facet_to_cell_links"] = max_facet_to_cell_links
-        # partitioner = dolfinx.cpp.mesh.create_cell_partitioner(ghost_mode, **part_kwargs)
+        if not hasattr(dolfinx.mesh, "create_cell_partitioner"):
+            partitioner = dolfinx.graph.partitioner()
+        else:
+            sig = inspect.signature(dolfinx.mesh.create_cell_partitioner)
+            part_kwargs = {}
+
+            if "max_facet_to_cell_links" in sig.parameters:
+                part_kwargs["max_facet_to_cell_links"] = max_facet_to_cell_links
+
+            partitioner = dolfinx.mesh.create_cell_partitioner(ghost_mode, **part_kwargs)
+
+    mesh_args: dict[str, Any] = {}
+    mesh_sig = inspect.signature(dolfinx.mesh.create_mesh)
+    if "max_facet_to_cell_links" in mesh_sig.parameters:
+        mesh_args["max_facet_to_cell_links"] = max_facet_to_cell_links
+    if "ghost_mode" in mesh_sig.parameters:
+        mesh_args["ghost_mode"] = ghost_mode
+    # TODO: Add more options here later
+    if "cell_weights" in mesh_sig.parameters:
+        mesh_args["cell_weights"] = None  # No cell weights provided, default to None
+    if "num_threads" in mesh_sig.parameters:
+        mesh_args["num_threads"] = 1  # Default to 1 thread, can be adjusted if needed
 
     return dolfinx.mesh.create_mesh(
         comm,
@@ -500,6 +509,7 @@ def _custom_partitioner(
         x=dist_in_data.x,
         e=domain,
         partitioner=partitioner,
+        **mesh_args,
     )
 
 
diff --git a/tests/create_legacy_data.py b/tests/create_legacy_data.py
index f4a578f..ba39985 100644
--- a/tests/create_legacy_data.py
+++ b/tests/create_legacy_data.py
@@ -14,7 +14,6 @@
 
 import dolfin
 import numpy as np
-import ufl_legacy as ufl
 
 
 def create_reference_data(
@@ -31,7 +30,12 @@ def create_reference_data(
     W = dolfin.VectorFunctionSpace(mesh, family, degree)
     x = dolfin.SpatialCoordinate(mesh)
 
-    f0 = ufl.conditional(ufl.gt(x[0], 0.5), x[1], 2 * x[0])
+    # NOTE: f0 must be exactly representable in the (family, degree) function space above.
+    # Legacy dolfin (FIAT-based quadrature) and current dolfinx (basix-based quadrature)
+    # use different quadrature rules, so a non-polynomial (e.g. conditional) integrand
+    # would project to slightly different values in each toolchain, making bit-exact
+    # comparisons in test_legacy_readers.py inherently flaky across dolfinx versions.
+    f0 = x[0] ** 2 + 2 * x[1] * x[2] - x[1]
     v0 = dolfin.project(f0, V)
     w0 = dolfin.interpolate(dolfin.Expression(("x[0]", "3*x[2]", "7*x[1]"), degree=1), W)
 
diff --git a/tests/test_legacy_readers.py b/tests/test_legacy_readers.py
index f8adf92..b567cb7 100644
--- a/tests/test_legacy_readers.py
+++ b/tests/test_legacy_readers.py
@@ -106,7 +106,9 @@ def test_legacy_function(backend):
     v = ufl.TestFunction(V)
     a = ufl.inner(u, v) * ufl.dx
     x = ufl.SpatialCoordinate(mesh)
-    f = ufl.conditional(ufl.gt(x[0], 0.5), x[1], 2 * x[0])
+    # NOTE: must stay exactly representable in the DG2 space (see tests/create_legacy_data.py)
+    # so the projection is quadrature-scheme independent when compared to legacy dolfin's.
+    f = x[0] ** 2 + 2 * x[1] * x[2] - x[1]
     L = ufl.inner(f, v) * ufl.dx
 
     if not dolfinx.has_petsc4py:
@@ -152,7 +154,9 @@ def test_read_legacy_function_from_checkpoint(backend):
     v = ufl.TestFunction(V)
     a = ufl.inner(u, v) * ufl.dx
     x = ufl.SpatialCoordinate(mesh)
-    f = ufl.conditional(ufl.gt(x[0], 0.5), x[1], 2 * x[0])
+    # NOTE: must stay exactly representable in the DG2 space (see tests/create_legacy_data.py)
+    # so the projection is quadrature-scheme independent when compared to legacy dolfin's.
+    f = x[0] ** 2 + 2 * x[1] * x[2] - x[1]
     L = ufl.inner(f, v) * ufl.dx
 
     if not dolfinx.has_petsc4py: