First implementation of tox_to_nox for tox 4

.github/workflows/ci.yml

@@ -18,6 +18,7 @@ jobs:
       matrix:
         os: [ubuntu-20.04, windows-latest, macos-latest]
         python-version: ["3.7", "3.8", "3.9", "3.10", "3.11", "3.12"]
+        tox-version: ["latest", "<4"]
     steps:
       - uses: actions/checkout@v4
       - name: Set up Python ${{ matrix.python-version }}
@@ -35,7 +36,33 @@ jobs:
         run: |
           python -m pip install --disable-pip-version-check .
       - name: Run tests on ${{ matrix.os }}
-        run: nox --non-interactive --error-on-missing-interpreter --session "tests-${{ matrix.python-version }}" -- --full-trace
+        run: nox --non-interactive --error-on-missing-interpreter --session "tests(python='${{ matrix.python-version }}', tox_version='${{ matrix.tox-version }}')" -- --full-trace
+      - name: Save coverage report
+        uses: actions/upload-artifact@v3
+        with:
+          name: coverage
+          path: .coverage.*
+
+  coverage:
+    needs: build
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v3
+      - name: Set up Python 3.11
+        uses: actions/setup-python@v4
+        with:
+          python-version: "3.11"
+      - name: Install Nox-under-test
+        run: |
+          python -m pip install --disable-pip-version-check .
+      - name: Download individual coverage reports
+        uses: actions/download-artifact@v3
+        with:
+          name: coverage
+      - name: Display structure of downloaded files
+        run: ls -aR
+      - name: Run coverage
+        run: nox --non-interactive --session "cover"
 
   lint:
     runs-on: ubuntu-latest

nox/tox4_to_nox.jinja2

@@ -0,0 +1,33 @@
+import nox
+
+{% for envname, envconfig in config.items()|sort: %}
+@nox.session({%- if envconfig.base_python %}python='{{envconfig.base_python}}'{%- endif %})
+def {{fixname(envname)}}(session):
+    {%- if envconfig.description != '' %}
+    """{{envconfig.description}}"""
+    {%- endif %}
+    {%- set envs = envconfig.get('set_env', {}) -%}
+    {%- for key, value in envs.items()|sort: %}
+    session.env['{{key}}'] = '{{value}}'
+    {%- endfor %}
+
+    {%- if envconfig.deps %}
+    session.install({{envconfig.deps}})
+    {%- endif %}
+
+    {%- if not envconfig.skip_install %}
+    {%- if envconfig.use_develop %}
+    session.install('-e', '.')
+    {%- else %}
+    session.install('.')
+    {%- endif -%}
+    {%- endif %}
+
+    {%- if envconfig.change_dir %}
+    session.chdir('{{envconfig.change_dir}}')
+    {%- endif %}
+
+    {%- for command in envconfig.commands %}
+    session.run({{command}})
+    {%- endfor %}
+{% endfor %}

nox/tox_to_nox.py

@@ -17,17 +17,31 @@
 from __future__ import annotations
 
 import argparse
+import os
 import pkgutil
+import re
 from collections.abc import Iterator
-from typing import Any
+from configparser import ConfigParser
+from pathlib import Path
+from subprocess import check_output
+from typing import Any, Iterable
 
 import jinja2
 import tox.config
+from tox import __version__ as TOX_VERSION
 
-_TEMPLATE = jinja2.Template(
-    pkgutil.get_data(__name__, "tox_to_nox.jinja2").decode("utf-8"),  # type: ignore[union-attr]
-    extensions=["jinja2.ext.do"],
-)
+TOX4 = TOX_VERSION[0] == "4"
+
+if TOX4:
+    _TEMPLATE = jinja2.Template(
+        pkgutil.get_data(__name__, "tox4_to_nox.jinja2").decode("utf-8"),  # type: ignore[union-attr]
+        extensions=["jinja2.ext.do"],
+    )
+else:
+    _TEMPLATE = jinja2.Template(
+        pkgutil.get_data(__name__, "tox_to_nox.jinja2").decode("utf-8"),  # type: ignore[union-attr]
+        extensions=["jinja2.ext.do"],
+    )
 
 
 def wrapjoin(seq: Iterator[Any]) -> str:
@@ -37,7 +51,7 @@ def wrapjoin(seq: Iterator[Any]) -> str:
 
 def fixname(envname: str) -> str:
     """Replace dashes with underscores and check if the result is a valid identifier."""
-    envname = envname.replace("-", "_")
+    envname = envname.replace("-", "_").replace("testenv:", "")
     if not envname.isidentifier():
         print(
             f"Environment {envname!r} is not a valid nox session name.\n"
@@ -58,7 +72,61 @@ def main() -> None:
 
     args = parser.parse_args()
 
-    config = tox.config.parseconfig([])
+    if TOX4:
+        output = check_output(["tox", "config"], text=True)
+        original_config = ConfigParser()
+        original_config.read_string(output)
+        config: dict[str, dict[str, Any]] = {}
+
+        for name, section in original_config.items():
+            if name == "DEFAULT":
+                continue
+
+            config[name] = dict(section)
+            # Convert set_env from string to dict
+            set_env = {}
+            for var in section.get("set_env", "").strip().splitlines():
+                k, v = var.split("=")
+                if k not in (
+                    "PYTHONHASHSEED",
+                    "PIP_DISABLE_PIP_VERSION_CHECK",
+                    "PYTHONIOENCODING",
+                ):
+                    set_env[k] = v
+
+            config[name]["set_env"] = set_env
+
+            config[name]["commands"] = [
+                wrapjoin(c.split()) for c in section["commands"].strip().splitlines()
+            ]
+
+            config[name]["deps"] = wrapjoin(section["deps"].strip().splitlines())
+
+            for option in "skip_install", "use_develop":
+                if section.get(option):
+                    if section[option] == "False":
+                        config[name][option] = False
+                    else:
+                        config[name][option] = True
+
+            if os.path.isabs(section["base_python"]) or re.match(
+                r"py\d+", section["base_python"]
+            ):
+                impl = (
+                    "python" if section["py_impl"] == "cpython" else section["py_impl"]
+                )
+                config[name]["base_python"] = impl + section["py_dot_ver"]
+
+            change_dir = Path(section.get("change_dir"))
+            rel_to_cwd = change_dir.relative_to(Path.cwd())
+            if str(rel_to_cwd) == ".":
+                config[name]["change_dir"] = None
+            else:
+                config[name]["change_dir"] = rel_to_cwd
+
+    else:
+        config = tox.config.parseconfig([])
+
     output = _TEMPLATE.render(config=config, wrapjoin=wrapjoin, fixname=fixname)
 
     write_output_to_file(output, args.output)

noxfile.py

@@ -31,22 +31,40 @@
     nox.options.sessions.append("conda_tests")
 
 
-@nox.session(python=["3.7", "3.8", "3.9", "3.10", "3.11", "3.12"])
-def tests(session: nox.Session) -> None:
+@nox.session
+@nox.parametrize(
+    "python, tox_version",
+    [
+        (python, tox_version)
+        for python in ("3.7", "3.8", "3.9", "3.10", "3.11", "3.12")
+        for tox_version in ("latest", "<4")
+    ],
+)
+def tests(session: nox.Session, tox_version: str) -> None:
     """Run test suite with pytest."""
+    # Because there is a dependency conflict between
+    # argcomplete and the latest tox (both depend on
+    # a different version of importlibmetadata for Py 3.7)
+    # pip installs tox 3 as the latest one for Py 3.7.
+    if session.python == "3.7" and tox_version == "latest":
+        return
+
     session.create_tmp()  # Fixes permission errors on Windows
     session.install("-r", "requirements-test.txt")
     session.install("-e", ".[tox_to_nox]")
+    if tox_version != "latest":
+        session.install(f"tox{tox_version}")
     session.run(
         "pytest",
         "--cov=nox",
         "--cov-config",
         "pyproject.toml",
         "--cov-report=",
         *session.posargs,
-        env={"COVERAGE_FILE": f".coverage.{session.python}"},
+        env={
+            "COVERAGE_FILE": f".coverage.{session.python}.tox.{tox_version.lstrip('<')}"
+        },
     )
-    session.notify("cover")
 
 
 @nox.session(python=["3.7", "3.8", "3.9", "3.10"], venv_backend="conda")

pyproject.toml

@@ -50,7 +50,7 @@ dependencies = [
 [project.optional-dependencies]
 tox_to_nox = [
   "jinja2",
-  "tox<4",
+  "tox",
 ]
 [project.urls]
 bug-tracker = "https://github.com/wntrblm/nox/issues"
@@ -67,6 +67,17 @@ metadata.allow-ambiguous-features = true # disable normalization (tox-to-nox) fo
 [tool.ruff]
 target-version = "py37"
 
+[tool.isort]
+profile = "black"
+
+[tool.coverage.run]
+branch = true
+relative_files = true
+omit = [ "nox/_typing.py" ]
+
+[tool.coverage.report]
+exclude_lines = [ "pragma: no cover", "if TYPE_CHECKING:", "@overload" ]
+
 [tool.ruff.lint]
 extend-select = [
   "B",           # flake8-bugbear