Enable flake8 and cov plugins only when installed. Avoid installing in PyPy.

conftest.py

@@ -19,24 +19,6 @@ collect_ignore = [
 ]
 
 
-def pytest_configure(config):
-    disable_coverage_on_pypy(config)
-
-
-def disable_coverage_on_pypy(config):
-    """
-    Coverage makes tests on PyPy unbearably slow, so disable it.
-    """
-    if '__pypy__' not in sys.builtin_module_names:
-        return
-
-    # Recommended at pytest-dev/pytest-cov#418
-    cov = config.pluginmanager.get_plugin('_cov')
-    cov.options.no_cov = True
-    if cov.cov_controller:
-        cov.cov_controller.pause()
-
-
 if sys.version_info < (3,):
     collect_ignore.append('setuptools/lib2to3_ex.py')
     collect_ignore.append('setuptools/_imp.py')

pyproject.toml

@@ -41,3 +41,9 @@ backend-path = ["."]
         directory = "misc"
         name = "Misc"
         showcontent = true
+
+[tool.jaraco.pytest.plugins.flake8]
+addopts = "--flake8"
+
+[tool.jaraco.pytest.plugins.cov]
+addopts = "--cov"

pytest.ini

 [pytest]
-addopts=--doctest-modules --flake8 --doctest-glob=pkg_resources/api_tests.txt --cov -r sxX
+addopts=--doctest-modules --doctest-glob=pkg_resources/api_tests.txt -r sxX
 norecursedirs=dist build *.egg setuptools/extern pkg_resources/extern pkg_resources/tests/data tools .* setuptools/_vendor pkg_resources/_vendor
 doctest_optionflags=ELLIPSIS ALLOW_UNICODE
 filterwarnings =

setup.cfg

@@ -68,10 +68,12 @@ tests =
     pytest>=3.7
     wheel
     coverage>=4.5.1
-    pytest-cov>=2.5.1
+    # Coverage is unbearably slow on PyPy
+    pytest-cov>=2.5.1; python_implementation != "PyPy"
     paver; python_version>="3.6"
     pip>=19.1 # For proper file:// URLs support.
     jaraco.envs
+    jaraco.test >= 3.1.1
 
 docs =
     # Keep these in sync with docs/requirements.txt