1 files changed, 113 insertions, 0 deletions
diff --git a/tests/unit/test_functional.py b/tests/unit/test_functional.py
new file mode 100644
index 0000000..2ea478e
--- /dev/null
+++ b/tests/unit/test_functional.py
@@ -0,0 +1,113 @@
+# SPDX-FileCopyrightText: Peter Pentchev <roam@ringlet.net>
+# SPDX-License-Identifier: BSD-2-Clause
+"""Load the Tox configuration, look for our tags thing."""
+
+from __future__ import annotations
+
+import contextlib
+import pathlib
+import shutil
+import subprocess
+import sys
+import tempfile
+from typing import TYPE_CHECKING
+
+import pytest
+import utf8_locale
+
+import tox_trivtags
+import tox_trivtags.parse as ttt_parse
+
+
+if sys.version_info >= (3, 11):
+    import contextlib as contextlib_chdir
+else:
+    import contextlib_chdir
+
+if TYPE_CHECKING:
+    from collections.abc import Callable, Iterator
+    from contextlib import AbstractContextManager
+    from typing import Final
+
+
+_EXPECTED: Final[dict[str, list[str]]] = {
+    "format": ["check", "quick"],
+    "reformat": ["format", "manual"],
+    "unit-tests-no-tox": ["tests"],
+    "unit-tests-tox-3": ["tests"],
+    "unit-tests-tox-4": ["tests"],
+    (".package" if tox_trivtags.HAVE_MOD_TOX_3 else ".pkg"): [],
+    "t-single": ["something"],
+    "t-several": ["all", "the", "things"],
+    "t-special": ["So,", "how many", "$tags", 'is "too many",', "'eh\"?"],
+}
+
+
+def copy_and_adapt(srcdir: pathlib.Path, dstdir: pathlib.Path) -> None:
+    """Copy some files over, adapt the tox.ini file."""
+    src_tox = srcdir / "tox.ini"
+    dst_tox = dstdir / "tox.ini"
+    lines: Final = src_tox.read_text(encoding="UTF-8").splitlines()
+    adapted: Final = [
+        line.replace(" \\", "") for line in lines if not line.startswith("minversion")
+    ]
+    dst_tox.write_text("".join(line + "\n" for line in adapted), encoding="UTF-8")
+    res: Final = subprocess.run(["diff", "-u", "--", src_tox, dst_tox], check=False)
+    assert res.returncode != 0
+
+    shutil.copytree(srcdir / "config", dstdir / "config")
+    shutil.copytree(srcdir / "requirements", dstdir / "requirements")
+    shutil.copy2(srcdir / "pyproject.toml", dstdir / "pyproject.toml")
+
+
+@contextlib.contextmanager
+def adapt_tox_cwd() -> Iterator[pathlib.Path]:
+    """If using Tox 3.x, copy the files over and adapt them."""
+    cwd: Final = pathlib.Path().absolute()
+    if not tox_trivtags.HAVE_MOD_TOX_3:
+        print("Not using Tox 3.x, no need to copy or adapt any files")
+        yield cwd
+        return
+
+    with tempfile.TemporaryDirectory() as toxd_name:
+        toxd = pathlib.Path(toxd_name).absolute()
+        print(f"Adapting files for Tox 3.x from {cwd} to {toxd}")
+        copy_and_adapt(cwd, toxd)
+        with contextlib_chdir.chdir(toxd):
+            yield toxd
+
+
+@contextlib.contextmanager
+def _cfg_filename_cwd() -> Iterator[pathlib.Path]:
+    """No arguments, parse the tox.ini file in the current directory."""
+    yield pathlib.Path("tox.ini")
+
+
+@contextlib.contextmanager
+def _cfg_filename_tempdir() -> Iterator[pathlib.Path]:
+    """Create a temporary directory, enter it, pass `-c` with the original cwd."""
+    cwd: Final = pathlib.Path().absolute()
+    with tempfile.TemporaryDirectory() as tempd:
+        print(f"Temporary directory: {tempd}; current directory: {cwd}")
+        with contextlib_chdir.chdir(tempd):
+            yield cwd / "tox.ini"
+
+
+def _do_test_run_showconfig(filename: pathlib.Path) -> None:
+    """Parse the `tox --showconfig` output."""
+    u8env: Final = utf8_locale.UTF8Detect().detect().env
+    print(f"Using {u8env['LC_ALL']} as a UTF-8-capable locale")
+
+    envs: Final = ttt_parse.parse_showconfig(filename, env=u8env)
+    print(f"Got some Tox config sections: {' '.join(sorted(envs))}")
+    for envname, expected in _EXPECTED.items():
+        print(f"- envname {envname!r} expected {expected!r}")
+        assert envs[envname].tags == expected
+
+
+@pytest.mark.parametrize("cfg_filename", [_cfg_filename_cwd, _cfg_filename_tempdir])
+def test_run_showconfig(cfg_filename: Callable[[], AbstractContextManager[pathlib.Path]]) -> None:
+    """Run `tox --showconfig` expecting tox.ini to be in the specified directory."""
+    print()
+    with adapt_tox_cwd(), cfg_filename() as filename:
+        _do_test_run_showconfig(filename)