56 files changed, 185 insertions, 218 deletions

diff --git a/.travis.yml b/.travis.yml
index fc5e3c1..78b4549 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -17,4 +17,4 @@ python:
 
 install: pip install -U -e .[test]
 
-script: python run-tests.py
+script: python -m unittest discover -v greenlet.tests
diff --git a/CHANGES.rst b/CHANGES.rst
index 835d9f4..a6bd00d 100644
--- a/CHANGES.rst
+++ b/CHANGES.rst
@@ -16,6 +16,16 @@
   sdists. PyPI has standardized on .tar.gz for all platforms.
 - (Packaging) Stop using a custom distutils command to build
   extensions. distutils is deprecated.
+- (Packaging) Remove the ability to use the deprecated command
+  ``python setup.py test``. Run greenlet tests with your favorite
+  unittest-compatible test runner, e.g., ``python -m unittest discover
+  greenlet.tests``. See `issue 185 <https://github.com/python-greenlet/greenlet/issues/185>`_.
+- (Packaging) The directory layout and resulting sdists have changed.
+  See `issue 184
+  <https://github.com/python-greenlet/greenlet/issues/184>`_.
+- The ``greenlet`` module is now a package. There are no API changes,
+  so all existing imports, including from C code, should continue to
+  work.
 - (Documentation) Publish the change log to https://greenlet.readthedocs.io
 - Drop support for Python 2.4, 2.5, 2.6, 3.0, 3.1, 3.2 and 3.4.
   The project metadata now includes the ``python_requires`` data to
diff --git a/LICENSE b/LICENSE
index 5e009e3..b73a4a1 100644
--- a/LICENSE
+++ b/LICENSE
@@ -1,8 +1,8 @@
 The following files are derived from Stackless Python and are subject to the
 same license as Stackless Python:
 
-	slp_platformselect.h
-	files in platform/ directory
+	src/greenlet/slp_platformselect.h
+	files in src/greenlet/platform/ directory
 
 See LICENSE.PSF and http://www.stackless.com/ for details.
 
diff --git a/MANIFEST.in b/MANIFEST.in
index 7acc777..21f02e8 100644
--- a/MANIFEST.in
+++ b/MANIFEST.in
@@ -1,70 +1,48 @@
-include .travis.yml
-include .readthedocs.yml
+###
+# Source code
+###
+recursive-include src *.py
+recursive-include src *.c
+recursive-include src *.cpp
+recursive-include src *.h
+recursive-include src *.cmd
+recursive-include src *.asm
+recursive-include src *.obj
+recursive-include benchmarks *
+
+###
+# Documentation
+###
+recursive-include docs *
+prune docs/_build
+
+###
+# Configuration and project files
+###
+
+include *.yml
+include *.txt
+include *.ini
+include *.rst
+include *.cfg
+include *.py
+include *.ini
+
+recursive-include appveyor *.cmd
+recursive-include appveyor *.ps1
+recursive-include appveyor *.py
+
 include AUTHORS
 include LICENSE
 include LICENSE.PSF
 include MANIFEST.in
-include CHANGES.rst
-include README.rst
-include appveyor.yml
-include appveyor/run_pip.py
-include appveyor/run_with_env.cmd
-include benchmarks/chain.py
-include conftest.py
-include dev-requirements.txt
-include docs/Makefile
-include docs/conf.py
-include docs/greenlet.rst
-include docs/index.rst
-include docs/changes.rst
-include docs/make.bat
-include greenlet.c
-include greenlet.h
+
+### XXX: Move these to a subdirectory.
 include make-manylinux
 include make-manifest
 include make-win-release
-include my_build_ext.py
-include platform/switch_aarch64_gcc.h
-include platform/switch_alpha_unix.h
-include platform/switch_amd64_unix.h
-include platform/switch_arm32_gcc.h
-include platform/switch_arm32_ios.h
-include platform/switch_csky_gcc.h
-include platform/switch_m68k_gcc.h
-include platform/switch_mips_unix.h
-include platform/switch_ppc64_linux.h
-include platform/switch_ppc_aix.h
-include platform/switch_ppc_linux.h
-include platform/switch_ppc_macosx.h
-include platform/switch_ppc_unix.h
-include platform/switch_riscv_unix.h
-include platform/switch_s390_unix.h
-include platform/switch_sparc_sun_gcc.h
-include platform/switch_x32_unix.h
-include platform/switch_x64_masm.asm
-include platform/switch_x64_masm.obj
-include platform/switch_x64_msvc.h
-include platform/switch_x86_msvc.h
-include platform/switch_x86_unix.h
-include run-tests.py
-include setup.cfg
-include setup.py
-include setup_switch_x64_masm.cmd
-include slp_platformselect.h
-include tests/__init__.py
-include tests/_test_extension.c
-include tests/_test_extension_cpp.cpp
-include tests/test_contextvars.py
-include tests/test_cpp.py
-include tests/test_extension_interface.py
-include tests/test_gc.py
-include tests/test_generator.py
-include tests/test_generator_nested.py
-include tests/test_greenlet.py
-include tests/test_leaks.py
-include tests/test_stack_saved.py
-include tests/test_throw.py
-include tests/test_tracing.py
-include tests/test_version.py
-include tests/test_weakref.py
-include tox.ini
+
+global-exclude *.pyc
+global-exclude *.pyd
+global-exclude *.so
+global-exclude .coverage
diff --git a/appveyor.yml b/appveyor.yml
index 5aae0e3..282ed80 100644
--- a/appveyor.yml
+++ b/appveyor.yml
@@ -101,11 +101,12 @@ install:
         https://ci.appveyor.com/api/projects/$env:APPVEYOR_ACCOUNT_NAME/$env:APPVEYOR_PROJECT_SLUG/history?recordsNumber=50).builds | `
         Where-Object pullRequestId -eq $env:APPVEYOR_PULL_REQUEST_NUMBER)[0].buildNumber) { `
           throw "There are newer queued builds for this pull request, failing early." }
-  - ECHO "Filesystem root:"
-  - ps: "ls \"C:/\""
+  ## Debugging
+  # - ECHO "Filesystem root:"
+  # - ps: "ls \"C:/\""
 
-  - ECHO "Installed SDKs:"
-  - ps: "if(Test-Path(\"C:/Program Files/Microsoft SDKs/Windows\")) {ls \"C:/Program Files/Microsoft SDKs/Windows\";}"
+  # - ECHO "Installed SDKs:"
+  # - ps: "if(Test-Path(\"C:/Program Files/Microsoft SDKs/Windows\")) {ls \"C:/Program Files/Microsoft SDKs/Windows\";}"
 
   # Install Python (from the official .msi of http://python.org) and pip when
   # not already installed.
@@ -147,9 +148,9 @@ install:
 build_script:
   - "%CMD_IN_ENV% python -m pip install -U -e .[test]"
 
-# XXX: setup.py test is deprecated
+
 test_script:
-  - "%CMD_IN_ENV% python setup.py test"
+  - "%CMD_IN_ENV% python -m unittest discover -v greenlet.tests"
 
 after_test:
   - "%CMD_IN_ENV% python setup.py bdist_wheel"
diff --git a/conftest.py b/conftest.py
deleted file mode 100644
index e3d92a1..0000000
--- a/conftest.py
+++ /dev/null
@@ -1,18 +0,0 @@
-# configuration file for py.test
-
-import sys, os
-from distutils.spawn import spawn
-
-
-def pytest_configure(config):
-    os.chdir(os.path.dirname(__file__))
-    cmd = [sys.executable, "setup.py", "-q", "build_ext", "-q", "-i"]
-    spawn(cmd, search_path=0)
-
-    from tests import build_test_extensions
-    build_test_extensions()
-
-
-def pytest_report_header(config):
-    import greenlet
-    return "greenlet %s from %s" % (greenlet.__version__, greenlet.__file__)
diff --git a/make-manifest b/make-manifest
deleted file mode 100755
index d9a3158..0000000
--- a/make-manifest
+++ /dev/null
@@ -1,21 +0,0 @@
-#! /usr/bin/env python
-
-# this file can be used as pre-commit hook with the following command:
-#
-#    ln -sf ../../make-manifest .git/hooks/pre-commit
-#
-
-import os
-
-
-def main():
-    files = sorted(set([x.strip() for x in os.popen("git ls-files")]) -
-                   set(("make-manifest", ".gitignore")))
-    with open("MANIFEST.in", "w") as f:
-        for x in files:
-            f.write("include %s\n" % x)
-
-    os.system("git add MANIFEST.in; git diff --cached MANIFEST.in | cat")
-
-if __name__ == '__main__':
-    main()
diff --git a/make-win-release b/make-win-release
deleted file mode 100755
index ee04485..0000000
--- a/make-win-release
+++ /dev/null
@@ -1,44 +0,0 @@
-#! /usr/bin/env python
-
-import sys, os, subprocess, re
-
-common_dist = ("bdist_wheel", "bdist_egg", "test")
-pyver2dist = {
-    "Python27": common_dist,
-    "Python27x64": common_dist,
-    "Python35": common_dist,
-    "Python35x64": common_dist,
-}
-
-
-def system(cmd):
-    sys.stdout.write("====> Running %s\n" % cmd)
-
-    popen = subprocess.Popen(cmd, stdout=subprocess.PIPE, stderr=subprocess.STDOUT, shell=True)
-    nl = True
-    while 1:
-        char = popen.stdout.read(1)
-        if not char:
-            break
-        if nl:
-            sys.stdout.write("    ")
-        sys.stdout.write(char)
-        sys.stdout.flush()
-        nl = char == "\n"
-
-    st = popen.wait()
-    if st != 0:
-        sys.exit("Error: command %r failed" % cmd)
-    sys.stdout.write("\n")
-
-
-def main():
-    here = os.path.dirname(os.path.dirname(sys.executable))
-    for pyver, dists in sorted(pyver2dist.items()):
-        exe = os.path.join(here, pyver, "python.exe")
-        for d in dists:
-            cmd = "%s setup.py -q %s" % (exe, d)
-            system(cmd)
-
-if __name__ == "__main__":
-    main()
diff --git a/setup.py b/setup.py
index 459633f..9500673 100755
--- a/setup.py
+++ b/setup.py
@@ -8,6 +8,7 @@ import platform
 # distutils is deprecated and vendored into setuptools now.
 from setuptools import setup
 from setuptools import Extension
+from setuptools import find_packages
 
 # workaround segfaults on openbsd and RHEL 3 / CentOS 3 . see
 # https://bitbucket.org/ambroff/greenlet/issue/11/segfault-on-openbsd-i386
@@ -26,19 +27,28 @@ def readfile(filename):
     with open(filename, 'r') as f:
         return f.read()
 
+GREENLET_SRC_DIR = 'src/greenlet/'
+GREENLET_HEADER_DIR = GREENLET_SRC_DIR
+GREENLET_HEADER = GREENLET_HEADER_DIR + 'greenlet.h'
+GREENLET_TEST_DIR = 'src/greenlet/tests/'
+# The location of the platform specific assembly files
+# for switching.
+GREENLET_PLATFORM_DIR = GREENLET_SRC_DIR + 'platform/'
+
 def _find_platform_headers():
-    return glob.glob("platform/switch_*.h")
+    return glob.glob(GREENLET_PLATFORM_DIR + "switch_*.h")
 
 if hasattr(sys, "pypy_version_info"):
     ext_modules = []
     headers = []
 else:
-    headers = ['greenlet.h']
+
+    headers = [GREENLET_HEADER]
 
     if sys.platform == 'win32' and '64 bit' in sys.version:
         # this works when building with msvc, not with 64 bit gcc
         # switch_x64_masm.obj can be created with setup_switch_x64_masm.cmd
-        extra_objects = ['platform/switch_x64_masm.obj']
+        extra_objects = [GREENLET_PLATFORM_DIR + 'switch_x64_masm.obj']
     else:
         extra_objects = []
 
@@ -51,11 +61,14 @@ else:
 
     ext_modules = [
         Extension(
-            name='greenlet',
-            sources=['greenlet.c'],
+            name='greenlet._greenlet',
+            sources=[GREENLET_SRC_DIR + 'greenlet.c'],
             extra_objects=extra_objects,
             extra_compile_args=extra_compile_args,
-            depends=['greenlet.h', 'slp_platformselect.h'] + _find_platform_headers()
+            depends=[
+                GREENLET_HEADER,
+                GREENLET_SRC_DIR + 'slp_platformselect.h',
+            ] + _find_platform_headers()
         ),
         # Test extensions.
         # XXX: We used to try hard to not include these in built
@@ -63,19 +76,19 @@ else:
         # layout with the test directory nested inside a greenlet directory.
         # See https://github.com/python-greenlet/greenlet/issues/184 and 189
         Extension(
-            '_test_extension',
-            [os.path.join('tests', '_test_extension.c')],
-            include_dirs=[os.path.curdir]
+            name='greenlet.tests._test_extension',
+            sources=[GREENLET_TEST_DIR + '_test_extension.c'],
+            include_dirs=[GREENLET_HEADER_DIR]
         ),
     ]
 
     if os.environ.get('GREENLET_TEST_CPP', 'yes').lower() not in ('0', 'no', 'false'):
         ext_modules.append(
             Extension(
-                '_test_extension_cpp',
-                [os.path.join('tests', '_test_extension_cpp.cpp')],
+                name='greenlet.tests._test_extension_cpp',
+                sources=[GREENLET_TEST_DIR + '_test_extension_cpp.cpp'],
                 language="c++",
-                include_dirs=[os.path.curdir]),
+                include_dirs=[GREENLET_HEADER_DIR]),
         )
 
 setup(
@@ -83,7 +96,7 @@ setup(
     version='1.0.0.dev0',
     description='Lightweight in-process concurrent programming',
     long_description=readfile("README.rst"),
-    url="https://github.com/python-greenlet/greenlet",
+    url="https://greenlet.readthedocs.io/",
     project_urls={
         'Bug Tracker': 'https://github.com/python-greenlet/greenlet/issues',
         'Source Code': 'https://github.com/python-greenlet/gevent/',
@@ -91,6 +104,9 @@ setup(
     },
     license="MIT License",
     platforms=['any'],
+    package_dir={'': 'src'},
+    packages=find_packages('src'),
+    include_package_data=True,
     headers=headers,
     ext_modules=ext_modules,
     classifiers=[
@@ -113,10 +129,10 @@ setup(
     extras_require={
         'docs': [
             'Sphinx',
-        ]
+        ],
+        'test': [
+        ],
     },
     python_requires=">=2.7,!=3.0.*,!=3.1.*,!=3.2.*,!=3.3.*,!=3.4.*",
-    # XXX: This is deprecated. appveyor.yml still uses it though.
-    test_suite='tests.test_collector',
     zip_safe=False,
 )
diff --git a/src/greenlet/__init__.py b/src/greenlet/__init__.py
new file mode 100644
index 0000000..7e9142f
--- /dev/null
+++ b/src/greenlet/__init__.py
@@ -0,0 +1,16 @@
+# -*- coding: utf-8 -*-
+"""
+The root of the greenlet package.
+"""
+from __future__ import absolute_import
+from __future__ import division
+from __future__ import print_function
+
+# TODO: Define a correct __all__
+# pylint:disable=unused-import
+# TODO: Move the definition of __version__ here, instead of the
+# C code. zest.releaser will find it here, but not in C.
+
+from ._greenlet import * # pylint:disable=wildcard-import
+from ._greenlet import __version__
+from ._greenlet import _C_API # pylint:disable=no-name-in-module
diff --git a/greenlet.c b/src/greenlet/greenlet.c
index aad4ba0..895931d 100644
--- a/greenlet.c
+++ b/src/greenlet/greenlet.c
@@ -1725,19 +1725,19 @@ static char* copy_on_greentype[] = {
 
 static struct PyModuleDef greenlet_module_def = {
 	PyModuleDef_HEAD_INIT,
-	"greenlet",
+	"greenlet._greenlet",
 	NULL,
 	-1,
 	GreenMethods,
 };
 
 PyMODINIT_FUNC
-PyInit_greenlet(void)
+PyInit__greenlet(void)
 #else
 #define INITERROR return
 
 PyMODINIT_FUNC
-initgreenlet(void)
+init_greenlet(void)
 #endif
 {
 	PyObject* m = NULL;
@@ -1750,7 +1750,7 @@ initgreenlet(void)
 #if PY_MAJOR_VERSION >= 3
 	m = PyModule_Create(&greenlet_module_def);
 #else
-	m = Py_InitModule("greenlet", GreenMethods);
+	m = Py_InitModule("greenlet._greenlet", GreenMethods);
 #endif
 	if (m == NULL)
 	{
@@ -1855,6 +1855,10 @@ initgreenlet(void)
 	_PyGreenlet_API[PyGreenlet_SetParent_NUM] =
 		(void *) PyGreenlet_SetParent;
 
+	/* XXX: Note that our module name is ``greenlet._greenlet``, but for
+	   backwards compatibility with existing C code, we need the _C_API to
+	   be directly in greenlet.
+	*/
 	c_api_object = PyCapsule_New((void *) _PyGreenlet_API, "greenlet._C_API", NULL);
 	if (c_api_object != NULL)
 	{
diff --git a/greenlet.h b/src/greenlet/greenlet.h
index b63f07b..68fc035 100644
--- a/greenlet.h
+++ b/src/greenlet/greenlet.h
@@ -134,6 +134,9 @@ static void **_PyGreenlet_API = NULL;
 	 _PyGreenlet_API[PyGreenlet_SetParent_NUM])
 
 /* Macro that imports greenlet and initializes C API */
+/* NOTE: This has actually moved to ``greenlet._greenlet._C_API``, but we
+   keep the older definition to be sure older code that might have a copy of
+   the header still works. */
 #define PyGreenlet_Import() \
 { \
 	_PyGreenlet_API = (void**)PyCapsule_Import("greenlet._C_API", 0); \
diff --git a/setup_switch_x64_masm.cmd b/src/greenlet/platform/setup_switch_x64_masm.cmd
index a7f1fc9..0928595 100644
--- a/setup_switch_x64_masm.cmd
+++ b/src/greenlet/platform/setup_switch_x64_masm.cmd
@@ -1,2 +1,2 @@
 call "C:\Program Files (x86)\Microsoft Visual Studio 9.0\VC\vcvarsall.bat" amd64

-ml64 /nologo /c /Fo platform\switch_x64_masm.obj platform\switch_x64_masm.asm

+ml64 /nologo /c /Fo switch_x64_masm.obj switch_x64_masm.asm

diff --git a/platform/switch_aarch64_gcc.h b/src/greenlet/platform/switch_aarch64_gcc.h
index 0b9d556..0b9d556 100644
--- a/platform/switch_aarch64_gcc.h
+++ b/src/greenlet/platform/switch_aarch64_gcc.h
diff --git a/platform/switch_alpha_unix.h b/src/greenlet/platform/switch_alpha_unix.h
index 216619f..216619f 100644
--- a/platform/switch_alpha_unix.h
+++ b/src/greenlet/platform/switch_alpha_unix.h
diff --git a/platform/switch_amd64_unix.h b/src/greenlet/platform/switch_amd64_unix.h
index 16b99b7..16b99b7 100644
--- a/platform/switch_amd64_unix.h
+++ b/src/greenlet/platform/switch_amd64_unix.h
diff --git a/platform/switch_arm32_gcc.h b/src/greenlet/platform/switch_arm32_gcc.h
index 035d6b9..035d6b9 100644
--- a/platform/switch_arm32_gcc.h
+++ b/src/greenlet/platform/switch_arm32_gcc.h
diff --git a/platform/switch_arm32_ios.h b/src/greenlet/platform/switch_arm32_ios.h
index e993707..e993707 100644
--- a/platform/switch_arm32_ios.h
+++ b/src/greenlet/platform/switch_arm32_ios.h
diff --git a/platform/switch_csky_gcc.h b/src/greenlet/platform/switch_csky_gcc.h
index 7486b94..7486b94 100644
--- a/platform/switch_csky_gcc.h
+++ b/src/greenlet/platform/switch_csky_gcc.h
diff --git a/platform/switch_m68k_gcc.h b/src/greenlet/platform/switch_m68k_gcc.h
index da761c2..da761c2 100644
--- a/platform/switch_m68k_gcc.h
+++ b/src/greenlet/platform/switch_m68k_gcc.h
diff --git a/platform/switch_mips_unix.h b/src/greenlet/platform/switch_mips_unix.h
index 1916b26..1916b26 100644
--- a/platform/switch_mips_unix.h
+++ b/src/greenlet/platform/switch_mips_unix.h
diff --git a/platform/switch_ppc64_aix.h b/src/greenlet/platform/switch_ppc64_aix.h
index e07b8de..e07b8de 100644
--- a/platform/switch_ppc64_aix.h
+++ b/src/greenlet/platform/switch_ppc64_aix.h
diff --git a/platform/switch_ppc64_linux.h b/src/greenlet/platform/switch_ppc64_linux.h
index 88e6847..88e6847 100644
--- a/platform/switch_ppc64_linux.h
+++ b/src/greenlet/platform/switch_ppc64_linux.h
diff --git a/platform/switch_ppc_aix.h b/src/greenlet/platform/switch_ppc_aix.h
index c7d476f..c7d476f 100644
--- a/platform/switch_ppc_aix.h
+++ b/src/greenlet/platform/switch_ppc_aix.h
diff --git a/platform/switch_ppc_linux.h b/src/greenlet/platform/switch_ppc_linux.h
index 0a71255..0a71255 100644
--- a/platform/switch_ppc_linux.h
+++ b/src/greenlet/platform/switch_ppc_linux.h
diff --git a/platform/switch_ppc_macosx.h b/src/greenlet/platform/switch_ppc_macosx.h
index 56e573f..56e573f 100644
--- a/platform/switch_ppc_macosx.h
+++ b/src/greenlet/platform/switch_ppc_macosx.h
diff --git a/platform/switch_ppc_unix.h b/src/greenlet/platform/switch_ppc_unix.h
index 2b3d307..2b3d307 100644
--- a/platform/switch_ppc_unix.h
+++ b/src/greenlet/platform/switch_ppc_unix.h
diff --git a/platform/switch_riscv_unix.h b/src/greenlet/platform/switch_riscv_unix.h
index 5b5ea98..5b5ea98 100644
--- a/platform/switch_riscv_unix.h
+++ b/src/greenlet/platform/switch_riscv_unix.h
diff --git a/platform/switch_s390_unix.h b/src/greenlet/platform/switch_s390_unix.h
index 6641854..6641854 100644
--- a/platform/switch_s390_unix.h
+++ b/src/greenlet/platform/switch_s390_unix.h
diff --git a/platform/switch_sparc_sun_gcc.h b/src/greenlet/platform/switch_sparc_sun_gcc.h
index 652b57f..652b57f 100644
--- a/platform/switch_sparc_sun_gcc.h
+++ b/src/greenlet/platform/switch_sparc_sun_gcc.h
diff --git a/platform/switch_x32_unix.h b/src/greenlet/platform/switch_x32_unix.h
index cb14ec1..cb14ec1 100644
--- a/platform/switch_x32_unix.h
+++ b/src/greenlet/platform/switch_x32_unix.h
diff --git a/platform/switch_x64_masm.asm b/src/greenlet/platform/switch_x64_masm.asm
index f5c72a2..f5c72a2 100644
--- a/platform/switch_x64_masm.asm
+++ b/src/greenlet/platform/switch_x64_masm.asm
diff --git a/platform/switch_x64_masm.obj b/src/greenlet/platform/switch_x64_masm.obj
index 64e3e6b..64e3e6b 100644
--- a/platform/switch_x64_masm.obj
+++ b/src/greenlet/platform/switch_x64_masm.obj
diff --git a/platform/switch_x64_msvc.h b/src/greenlet/platform/switch_x64_msvc.h
index 601ea56..601ea56 100644
--- a/platform/switch_x64_msvc.h
+++ b/src/greenlet/platform/switch_x64_msvc.h
diff --git a/platform/switch_x86_msvc.h b/src/greenlet/platform/switch_x86_msvc.h
index 010a22c..010a22c 100644
--- a/platform/switch_x86_msvc.h
+++ b/src/greenlet/platform/switch_x86_msvc.h
diff --git a/platform/switch_x86_unix.h b/src/greenlet/platform/switch_x86_unix.h
index 3a95186..3a95186 100644
--- a/platform/switch_x86_unix.h
+++ b/src/greenlet/platform/switch_x86_unix.h
diff --git a/slp_platformselect.h b/src/greenlet/slp_platformselect.h
index b5e8eb6..b5e8eb6 100644
--- a/slp_platformselect.h
+++ b/src/greenlet/slp_platformselect.h
diff --git a/src/greenlet/tests/__init__.py b/src/greenlet/tests/__init__.py
new file mode 100644
index 0000000..e69de29
--- /dev/null
+++ b/src/greenlet/tests/__init__.py
diff --git a/tests/_test_extension.c b/src/greenlet/tests/_test_extension.c
index ec8b70c..ec8b70c 100644
--- a/tests/_test_extension.c
+++ b/src/greenlet/tests/_test_extension.c
diff --git a/tests/_test_extension_cpp.cpp b/src/greenlet/tests/_test_extension_cpp.cpp
index 3b26571..fc3adad 100644
--- a/tests/_test_extension_cpp.cpp
+++ b/src/greenlet/tests/_test_extension_cpp.cpp
@@ -74,7 +74,7 @@ static PyMethodDef test_methods[] = {
 
 static struct PyModuleDef moduledef = {
 	PyModuleDef_HEAD_INIT,
-	"_test_extension_cpp",
+	"greenlet.tests._test_extension_cpp",
 	NULL,
 	0,
 	test_methods,
@@ -97,7 +97,7 @@ init_test_extension_cpp(void)
 #if PY_MAJOR_VERSION >= 3
 	module = PyModule_Create(&moduledef);
 #else
-	module = Py_InitModule("_test_extension_cpp", test_methods);
+	module = Py_InitModule("greenlet.tests._test_extension_cpp", test_methods);
 #endif
 
 	if (module == NULL) {
diff --git a/tests/test_contextvars.py b/src/greenlet/tests/test_contextvars.py
index 02873c5..49b7c0d 100644
--- a/tests/test_contextvars.py
+++ b/src/greenlet/tests/test_contextvars.py
@@ -6,7 +6,7 @@ from functools import partial
 
 from greenlet import greenlet
 from greenlet import getcurrent
-from greenlet import GREENLET_USE_CONTEXT_VARS
+
 
 try:
     from contextvars import Context
@@ -15,7 +15,8 @@ try:
 except ImportError:
     Context = ContextVar = copy_context = None
 
-@unittest.skipUnless(GREENLET_USE_CONTEXT_VARS, "ContextVar not supported")
+# We don't support testing if greenlet's built-in context var support is disabled.
+@unittest.skipUnless(Context is not None, "ContextVar not supported")
 class ContextVarsTests(unittest.TestCase):
     def _new_ctx_run(self, *args, **kwargs):
         return copy_context().run(*args, **kwargs)
@@ -249,7 +250,7 @@ class ContextVarsTests(unittest.TestCase):
         gr.gr_context = ctx
         self.assertIs(gr.gr_context, ctx)
 
-@unittest.skipIf(GREENLET_USE_CONTEXT_VARS, "ContextVar supported")
+@unittest.skipIf(Context is not None, "ContextVar supported")
 class NoContextVarsTests(unittest.TestCase):
     def test_contextvars_errors(self):
         let1 = greenlet(getcurrent().switch)
diff --git a/tests/test_cpp.py b/src/greenlet/tests/test_cpp.py
index ad1888f..741ea10 100644
--- a/tests/test_cpp.py
+++ b/src/greenlet/tests/test_cpp.py
@@ -1,7 +1,10 @@
+from __future__ import print_function
+from __future__ import absolute_import
+
 import unittest
 
 import greenlet
-import _test_extension_cpp
+from . import _test_extension_cpp
 
 
 class CPPTests(unittest.TestCase):
diff --git a/tests/test_extension_interface.py b/src/greenlet/tests/test_extension_interface.py
index e7bfbfd..bc87452 100644
--- a/tests/test_extension_interface.py
+++ b/src/greenlet/tests/test_extension_interface.py
@@ -1,8 +1,11 @@
+from __future__ import print_function
+from __future__ import absolute_import
+
 import sys
 import unittest
 
 import greenlet
-import _test_extension
+from . import _test_extension
 
 
 class CAPITests(unittest.TestCase):
diff --git a/tests/test_gc.py b/src/greenlet/tests/test_gc.py
index a2a41ca..a2a41ca 100644
--- a/tests/test_gc.py
+++ b/src/greenlet/tests/test_gc.py
diff --git a/tests/test_generator.py b/src/greenlet/tests/test_generator.py
index 62f9f26..62f9f26 100644
--- a/tests/test_generator.py
+++ b/src/greenlet/tests/test_generator.py
diff --git a/tests/test_generator_nested.py b/src/greenlet/tests/test_generator_nested.py
index 6b4f023..6b4f023 100644
--- a/tests/test_generator_nested.py
+++ b/src/greenlet/tests/test_generator_nested.py
diff --git a/tests/test_greenlet.py b/src/greenlet/tests/test_greenlet.py
index 5a3fe10..5a3fe10 100644
--- a/tests/test_greenlet.py
+++ b/src/greenlet/tests/test_greenlet.py
diff --git a/tests/test_leaks.py b/src/greenlet/tests/test_leaks.py
index 2b24ea0..2b24ea0 100644
--- a/tests/test_leaks.py
+++ b/src/greenlet/tests/test_leaks.py
diff --git a/tests/test_stack_saved.py b/src/greenlet/tests/test_stack_saved.py
index 6c7353b..6c7353b 100644
--- a/tests/test_stack_saved.py
+++ b/src/greenlet/tests/test_stack_saved.py
diff --git a/tests/test_throw.py b/src/greenlet/tests/test_throw.py
index a2014a9..a2014a9 100644
--- a/tests/test_throw.py
+++ b/src/greenlet/tests/test_throw.py
diff --git a/tests/test_tracing.py b/src/greenlet/tests/test_tracing.py
index 4f34b15..4f34b15 100644
--- a/tests/test_tracing.py
+++ b/src/greenlet/tests/test_tracing.py
diff --git a/src/greenlet/tests/test_version.py b/src/greenlet/tests/test_version.py
new file mode 100755
index 0000000..f4ea056
--- /dev/null
+++ b/src/greenlet/tests/test_version.py
@@ -0,0 +1,49 @@
+#! /usr/bin/env python
+from __future__ import absolute_import
+from __future__ import print_function
+
+import sys
+import os
+import re
+import unittest
+
+import greenlet
+
+class VersionTests(unittest.TestCase):
+    def test_version(self):
+        def find_dominating_file(name):
+            here = os.path.abspath(os.path.dirname(__file__))
+            for i in range(10):
+                up = ['..'] * i
+                path = [here] + up + [name]
+                fname = os.path.join(*path)
+                fname = os.path.abspath(fname)
+                if os.path.exists(fname):
+                    return fname
+            raise AssertionError("Could not find file " + name + "; last checked " + fname)
+
+        try:
+            setup_py = find_dominating_file('setup.py')
+        except AssertionError as e:
+            raise unittest.SkipTest("Unable to find setup.py; must be out of tree. " + str(e))
+
+        try:
+            greenlet_h = find_dominating_file('greenlet.h')
+        except AssertionError as e:
+            if '.tox' in os.path.abspath(os.path.dirname(__file__)):
+                raise unittest.SkipTest("Unable to find greenlet.h while running in tox")
+            raise
+
+        with open(greenlet_h) as f:
+            greenlet_h = f.read()
+
+        hversion, = re.findall('GREENLET_VERSION "(.*)"', greenlet_h)
+
+
+
+        invoke_setup = "%s %s --version" % (sys.executable, setup_py)
+        with os.popen(invoke_setup) as f:
+            sversion = f.read().strip()
+
+        self.assertEqual(sversion, hversion)
+        self.assertEqual(sversion, greenlet.__version__)
diff --git a/tests/test_weakref.py b/src/greenlet/tests/test_weakref.py
index 6a2ff06..6a2ff06 100644
--- a/tests/test_weakref.py
+++ b/src/greenlet/tests/test_weakref.py
diff --git a/tests/__init__.py b/tests/__init__.py
deleted file mode 100644
index 3ea15d8..0000000
--- a/tests/__init__.py
+++ /dev/null
@@ -1,14 +0,0 @@
-import os
-import glob
-import unittest
-
-def test_collector():
-    """Collect all tests under the tests directory and return a
-    unittest.TestSuite
-    """
-    tests_dir = os.path.realpath(os.path.dirname(__file__))
-    test_module_list = [
-        'tests.%s' % os.path.splitext(os.path.basename(t))[0]
-        for t in glob.glob(os.path.join(tests_dir, 'test_*.py'))
-    ]
-    return unittest.TestLoader().loadTestsFromNames(test_module_list)
diff --git a/tests/test_version.py b/tests/test_version.py
deleted file mode 100755
index 5870e52..0000000
--- a/tests/test_version.py
+++ /dev/null
@@ -1,20 +0,0 @@
-#! /usr/bin/env python
-
-import sys, os, re, unittest, greenlet
-
-def readclose(f):
-    try:
-        return f.read()
-    finally:
-        f.close()
-
-def readfile(filename):
-    return readclose(open(filename))
-
-class VersionTests(unittest.TestCase):
-    def test_version(self):
-        upfile = lambda p: os.path.join(os.path.dirname(__file__), "..", p)
-        hversion, = re.findall('GREENLET_VERSION "(.*)"', readfile(upfile("greenlet.h")))
-        sversion = readclose(os.popen("%s %s --version" % (sys.executable, upfile("setup.py")))).strip()
-        self.assertFalse(sversion != hversion)
-        self.assertFalse(sversion != greenlet.__version__)
diff --git a/tox.ini b/tox.ini
index 3095831..eb55d18 100644
--- a/tox.ini
+++ b/tox.ini
@@ -3,7 +3,7 @@ envlist =
     py27,py35,py36,py37,py38,py39,docs
 
 [testenv]
-commands=python run-tests.py
+commands=python -m unittest discover -v greenlet.tests
 sitepackages=False