Migrate tox config from ini to toml (#443)

This also replaces our tox-ini-fmt pre-commit hook with tox-toml-fmt.

.pre-commit-config.yaml

@@ -14,11 +14,10 @@ repos:
     hooks:
       - id: codespell
         additional_dependencies: ["tomli>=2.0.1"]
-  - repo: https://github.com/tox-dev/tox-ini-fmt
-    rev: "1.4.1"
+  - repo: https://github.com/tox-dev/tox-toml-fmt
+    rev: "v1.0.0"
     hooks:
-      - id: tox-ini-fmt
-        args: ["-p", "fix"]
+      - id: tox-toml-fmt
   - repo: https://github.com/tox-dev/pyproject-fmt
     rev: "v2.5.0"
     hooks:

tox.toml

@@ -0,0 +1,81 @@
+requires = [ "tox>=4.2", "tox-uv>=1.11.3" ]
+env_list = [
+  "fix",
+  "3.13",
+  "3.12",
+  "3.11",
+  "3.10",
+  "3.9",
+  "3.8",
+  "type",
+  "pkg_meta",
+]
+skip_missing_interpreters = true
+
+[env_run_base]
+description = "run the unit tests with pytest under {base_python}"
+package = "wheel"
+wheel_build_env = ".pkg"
+extras = [ "graphviz", "test" ]
+pass_env = [ "DIFF_AGAINST", "PYTEST_*" ]
+set_env.COVERAGE_FILE = "{work_dir}/.coverage.{env_name}"
+commands = [
+  [
+    "python",
+    "-m",
+    "pytest",
+    "{tty:--color=yes}",
+    { replace = "posargs", extend = true, default = [
+      "--cov",
+      "{env_site_packages_dir}{/}pipdeptree",
+      "--cov",
+      "{tox_root}{/}tests",
+      "--cov-config=pyproject.toml",
+      "--no-cov-on-fail",
+      "--cov-report",
+      "term-missing:skip-covered",
+      "--cov-context=test",
+      "--cov-report",
+      "html:{env_tmp_dir}{/}htmlcov",
+      "--cov-report",
+      "xml:{work_dir}{/}coverage.{env_name}.xml",
+      "--junitxml",
+      "{work_dir}{/}junit.{env_name}.xml",
+      "tests",
+    ] },
+  ],
+  [
+    "diff-cover",
+    "--compare-branch",
+    "{env:DIFF_AGAINST:origin/main}",
+    "{work_dir}{/}coverage.{env_name}.xml",
+    "--fail-under",
+    "100",
+  ],
+]
+
+[env.fix]
+description = "format the code base to adhere to our styles, and complain about what we cannot do automatically"
+skip_install = true
+deps = [ "pre-commit-uv>=4.1.3" ]
+commands = [ [ "pre-commit", "run", "--all-files", "--show-diff-on-failure" ] ]
+
+[env.type]
+description = "run type check on code base"
+deps = [ "mypy==1.11.2" ]
+commands = [ [ "mypy", "src" ], [ "mypy", "tests" ] ]
+
+[env.pkg_meta]
+description = "check that the long description is valid"
+skip_install = true
+deps = [ "check-wheel-contents>=0.6", "twine>=5.1.1", "uv>=0.4.10" ]
+commands = [
+  [ "uv", "build", "--sdist", "--wheel", "--out-dir", "{env_tmp_dir}", "." ],
+  [ "twine", "check", "{env_tmp_dir}{/}*" ],
+  [ "check-wheel-contents", "--no-config", "{env_tmp_dir}" ],
+]
+
+[env.dev]
+description = "generate a DEV environment"
+package = "editable"
+commands = [ [ "uv", "pip", "tree" ], [ "python", "-c", "import sys; print(sys.executable)" ] ]