Drop support for tox < 3.13 (< 3.15 with Python 3.8+)

We have tox 3.13 in Fedora 31 running on Python 3.7
We have tox 3.15 in Fedora 32 running on Python 3.8

.github/workflows/main.yaml

@@ -19,10 +19,10 @@ jobs:
         tox_env:
         # This information is repeated in tox.ini
         # (see https://github.com/fedora-python/tox-github-action/issues/8)
-        - py36-tox35
-        - py37-tox35
-        - py38-tox35
-        - py39-tox35
+        - py36-tox313
+        - py37-tox313
+        - py38-tox315
+        - py39-tox315
 
         - py36-toxrelease
         - py37-toxrelease

setup.py

@@ -18,7 +18,13 @@ setup(
     package_dir={"": "src"},
     packages=find_packages("src"),
     entry_points={"tox": ["current-env = tox_current_env.hooks"]},
-    install_requires=["tox>=3.5"],
+    install_requires=[
+        # We support tox 3.13 only to support Fedora 31.
+        # Fedora's tox 3.13 is patched to support Python 3.8 and 3.9,
+        # but the one downloaded from PyPI isn't and it doesn't work properly.
+        "tox>=3.15; python_version >= '3.8'",
+        "tox>=3.13; python_version < '3.8'",
+    ],
     python_requires=">=3.6",
     classifiers=[
         "Development Status :: 3 - Alpha",

src/tox_current_env/hooks.py

@@ -177,8 +177,6 @@ def tox_runtest(venv, redirect):
         return True
 
 
-if hasattr(tox.hookspecs, "tox_cleanup"):
-
 @tox.hookimpl
 def tox_cleanup(session):
     """Remove the fake virtualenv not to collide with regular tox

tests/test_integration.py

@@ -49,8 +49,8 @@ def is_available(python):
 
 
 TOX_VERSION = version.parse(tox("--version").stdout.split(" ")[0])
-TOX38 = TOX_VERSION >= version.parse("3.8")
-needs_tox38 = pytest.mark.skipif(not TOX38, reason="This test needs at least tox 3.8")
+TOX313 = TOX_VERSION < version.parse("3.14")
+
 
 needs_py36789 = pytest.mark.skipif(
     not all((is_available(f"python3.{x}") for x in range(6, 10))),
@@ -195,8 +195,10 @@ def test_regular_run():
     assert "/.tox/py39 is the exec_prefix" in lines[3]
     assert "congratulations" in result.stdout
     for y in 6, 7, 8, 9:
-        if y == 9 and not TOX38:
-            # tox 3.5 cannot handle Python 3.9 venvs
+        if TOX313 and y > 8:
+            # there is a bug in tox < 3.14,
+            # it creates venv with /usr/bin/python3 if the version is unknown
+            # See https://src.fedoraproject.org/rpms/python-tox/pull-request/15
             continue
         for pkg in "py", "six", "test":
             sitelib = DOT_TOX / f"py3{y}/lib/python3.{y}/site-packages"
@@ -217,7 +219,6 @@ def test_regular_run_native_toxenv():
         assert len(list(sitelib.glob(f"{pkg}-*.dist-info"))) == 1
 
 
-@needs_tox38
 def test_regular_after_current_is_supported():
     result = tox("-e", NATIVE_TOXENV, "--current-env")
     assert result.stdout.splitlines()[0] == NATIVE_EXEC_PREFIX_MSG
@@ -237,7 +238,6 @@ def test_regular_after_killed_current_is_not_supported():
     assert "--recreate" in result.stderr
 
 
-@needs_tox38
 def test_regular_after_first_deps_only_is_supported():
     result = tox("-e", NATIVE_TOXENV, "--print-deps-only")
     assert result.stdout.splitlines()[0] == "six"

tox.ini

@@ -2,14 +2,15 @@
 
 # This information is repeated in .github/workflows/main.yaml
 # (see https://github.com/fedora-python/tox-github-action/issues/8)
-envlist = {py36,py37,py38,py39}-tox{35,release,master}
+envlist = {py36,py37,py38,py39}-tox{release,master},{py36,py37}-tox313,{py38,py39}-tox315
 
 [testenv]
 deps=
     pytest
     pytest-xdist
     packaging
-    tox35: tox >=3.5,<3.6
+    tox313: tox >=3.13,<3.14
+    tox315: tox >=3.15,<3.16
     toxrelease: tox
     toxmaster: git+https://github.com/tox-dev/tox.git@master
 commands =