Move test dependencies to package metadata.

.github/workflows/python-tests.yml

@@ -55,7 +55,7 @@ jobs:
       uses: actions/cache@v1
       with:
         path: ~/.cache/pip
-        key: ${{ runner.os }}-pip-${{ hashFiles('docs/requirements.txt') }}-${{ hashFiles('tests/requirements.txt') }}-${{ hashFiles('tox.ini') }}
+        key: ${{ runner.os }}-pip-${{ hashFiles('setup.cfg') }}
         restore-keys: |
           ${{ runner.os }}-pip-
           ${{ runner.os }}-

.readthedocs.yml

@@ -1,4 +1,5 @@
 python:
   version: 3
-  requirements_file: docs/requirements.txt
-  pip_install: false
+  extra_requirements:
+  - docs
+  pip_install: true

changelog.d/1981.change.rst

@@ -0,0 +1 @@
+Setuptools now declares its ``tests`` and ``docs`` dependencies in metadata (extras).

setup.cfg

@@ -55,5 +55,25 @@ exclude = *.tests
 [options.extras_require]
 ssl =
     wincertstore==0.2; sys_platform=='win32'
+
 certs =
     certifi==2016.9.26
+
+tests =
+    mock
+    pytest-flake8
+    flake8-2020; python_version>="3.6"
+    virtualenv>=13.0.0
+    pytest-virtualenv>=1.2.7
+    pytest>=3.7
+    wheel
+    coverage>=4.5.1
+    pytest-cov>=2.5.1
+    paver; python_version>="3.6"
+    futures; python_version=="2.7"
+    pip>=19.1 # For proper file:// URLs support.
+
+docs =
+    sphinx
+    jaraco.packaging>=6.1
+    rst.linker>=1.9

setuptools/tests/test_virtualenv.py

@@ -12,6 +12,17 @@
 from .test_easy_install import make_nspkg_sdist
 
 
+@pytest.fixture(autouse=True)
+def disable_requires_python(monkeypatch):
+    """
+    Disable Requires-Python on Python 2.7
+    """
+    if sys.version_info > (3,):
+        return
+
+    monkeypatch.setenv('PIP_IGNORE_REQUIRES_PYTHON', 'true')
+
+
 @pytest.fixture(autouse=True)
 def pytest_virtualenv_works(virtualenv):
     """

tools/tox_pip.py

@@ -1,6 +1,7 @@
 import os
 import subprocess
 import sys
+import re
 
 
 def remove_setuptools():
@@ -20,18 +21,62 @@ def bootstrap():
     subprocess.check_call(cmd)
 
 
-def pip(args):
-    # Honor requires-python when installing test suite dependencies
-    if any('-r' in arg for arg in args):
-        os.environ['PIP_IGNORE_REQUIRES_PYTHON'] = '0'
+def is_install_self(args):
+    """
+    Do the args represent an install of .?
+    """
+    def strip_extras(arg):
+        match = re.match(r'(.*)?\[.*\]$', arg)
+        return match.group(1) if match else arg
+
+    return (
+        'install' in args
+        and any(
+            arg in ['.', os.getcwd()]
+            for arg in map(strip_extras, args)
+        )
+    )
+
+
+def pip(*args):
+    cmd = [sys.executable, '-m', 'pip'] + list(args)
+    return subprocess.check_call(cmd)
+
+
+def test_dependencies():
+    from ConfigParser import ConfigParser
+
+    def clean(dep):
+        spec, _, _ = dep.partition('#')
+        return spec.strip()
 
-    if '.' in args:
+    parser = ConfigParser()
+    parser.read('setup.cfg')
+    raw = parser.get('options.extras_require', 'tests').split('\n')
+    return filter(None, map(clean, raw))
+
+
+def disable_python_requires():
+    """
+    On Python 2, install the dependencies that are selective
+    on Python version while honoring REQUIRES_PYTHON, then
+    disable REQUIRES_PYTHON so that pip can install this
+    checkout of setuptools.
+    """
+    pip('install', *test_dependencies())
+    os.environ['PIP_IGNORE_REQUIRES_PYTHON'] = 'true'
+
+
+def run(args):
+    os.environ['PIP_USE_PEP517'] = 'true'
+
+    if is_install_self(args):
         remove_setuptools()
         bootstrap()
+        sys.version_info > (3,) or disable_python_requires()
 
-    cmd = [sys.executable, '-m', 'pip'] + args
-    subprocess.check_call(cmd)
+    pip(*args)
 
 
 if __name__ == '__main__':
-    pip(sys.argv[1:])
+    run(sys.argv[1:])

tox.ini

@@ -13,18 +13,18 @@ requires =
 pip = python {toxinidir}/tools/tox_pip.py
 
 [testenv]
-deps=-r{toxinidir}/setuptools/tests/requirements.txt
 pip_version = pip
 install_command = {[helpers]pip} install {opts} {packages}
 list_dependencies_command = {[helpers]pip} freeze --all
 setenv =
 	COVERAGE_FILE={toxworkdir}/.coverage.{envname}
-	py{27,py2}: PIP_IGNORE_REQUIRES_PYTHON=true
 # TODO: The passed environment variables came from copying other tox.ini files
 # These should probably be individually annotated to explain what needs them.
 passenv=APPDATA HOMEDRIVE HOMEPATH windir APPVEYOR APPVEYOR_* CI CODECOV_* TRAVIS TRAVIS_* NETWORK_REQUIRED
 commands=pytest --cov-config={toxinidir}/tox.ini --cov-report= {posargs}
 usedevelop=True
+extras =
+	tests
 
 
 [testenv:coverage]
@@ -44,12 +44,12 @@ skip_install=True
 commands=codecov -X gcov --file {toxworkdir}/coverage.xml
 
 [testenv:docs]
-deps = -r{toxinidir}/docs/requirements.txt
-skip_install=True
+extras =
+        docs
+        testing
+changedir = docs
 commands =
-    python -m bootstrap
-    sphinx-build -W -b html -d {envtmpdir}/doctrees docs docs/build/html
-    sphinx-build -W -b man -d {envtmpdir}/doctrees docs docs/build/man
+        python -m sphinx . {toxinidir}/build/html
 
 [coverage:run]
 source=