First part of fixing #1349: Allow test.support.is_resource_enabled to do its...

First part of fixing #1349: Allow test.support.is_resource_enabled to do its usual thing in monkey-patched tests (and eventually our own tests).

By default, this will always return true, so nothing will be skipped. An eventual step is to add options to the testrunner to control which resources are available, analogous to what test.regrtest can do.

Because we always spawn fresh subprocesses, we'll have to do this with environment variables and be sure we have the right setup code always invoked.

_setuputils.py

@@ -83,7 +83,6 @@ def _parse_environ(key):
                      'Please set it to 1, 0 or an empty string' % (key, value))
 
 IGNORE_CFFI = _parse_environ("GEVENT_NO_CFFI_BUILD")
-SKIP_LIBUV = _parse_environ('GEVENT_NO_LIBUV_BUILD')
 
 def _get_config_value(key, defkey, path=None):
     """

setup.py

@@ -18,7 +18,6 @@ from _setuputils import read_version
 from _setuputils import system
 from _setuputils import PYPY, WIN
 from _setuputils import IGNORE_CFFI
-from _setuputils import SKIP_LIBUV
 from _setuputils import ConfiguringBuildExt
 from _setuputils import GeventClean
 from _setuputils import BuildFailed
@@ -193,10 +192,7 @@ if not WIN:
         LIBEV_CFFI_MODULE
     )
 
-if not SKIP_LIBUV:
-    # libuv can't be built on manylinux1 because it needs glibc >= 2.12
-    # but manylinux1 has only 2.5, so we set SKIP_LIBUV in the script make-manylinux
-    cffi_modules.append(LIBUV_CFFI_MODULE)
+cffi_modules.append(LIBUV_CFFI_MODULE)
 
 greenlet_requires = [
     # We need to watch our greenlet version fairly carefully,

src/gevent/testing/monkey_test.py

@@ -21,12 +21,7 @@ monkey.patch_all(**kwargs)
 from .sysinfo import RUNNING_ON_APPVEYOR
 from .sysinfo import PY37
 from .patched_tests_setup import disable_tests_in_source
-try:
-    from test import support
-except ImportError:
-    from test import test_support as support
-support.is_resource_enabled = lambda *args: True
-del support.use_resources
+
 if RUNNING_ON_APPVEYOR and PY37:
     # 3.7 added a stricter mode for thread cleanup.
     # It appears to be unstable on Windows (at least appveyor)

src/gevent/testing/support.py

@@ -17,22 +17,72 @@
 # LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 # OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 # THE SOFTWARE.
+"""
+A re-export of the support module from Python's test package, with some
+version compatibility shims and overrides.
+"""
 
-# A re-export of the support module from Python's test package, with some
-# compatibility shims.
 
-# Note that this imports a lot of modules.
+import sys
 
-# pylint:disable=wildcard-import,unused-wildcard-import
+# Proxy through, so that changes to this module reflect in the
+# real module too. In 3.7, this is natively supported.
 
-try:
-    # Renamed from test_support in Python 3,
-    # *and* in 2.7.14 (but with a BWC module)
-    from test.support import *
-except ImportError:
-    from test.test_support import *
+class _Default(object):
+    # A descriptor-like object that will
+    # only be used if the actual stdlib module
+    # doesn't have the value.
 
-try:
-    HOSTv6
-except NameError:
-    HOSTv6 = '::1'
+    def __init__(self, value):
+        self.value = value
+
+class _ModuleProxy(object):
+
+    __slots__ = ('_orig_mod', '_stdlib_support')
+
+    def __init__(self):
+        self._orig_mod = sys.modules[__name__]
+        self._stdlib_support = None
+
+    def __get_stdlib_support(self):
+        if self._stdlib_support is None:
+            try:
+                # Renamed from test_support in Python 3,
+                # *and* in 2.7.14 (but with a BWC module)
+                from test import support as stdlib_support
+            except ImportError:
+                from test import test_support as stdlib_support
+            self._stdlib_support = stdlib_support
+
+        return self._stdlib_support
+
+    def __getattr__(self, name):
+        try:
+            local_val = getattr(self._orig_mod, name)
+        except AttributeError:
+            return getattr(self.__get_stdlib_support(), name)
+
+        if isinstance(local_val, _Default):
+            try:
+                return getattr(self.__get_stdlib_support(), name)
+            except AttributeError:
+                return local_val.value
+            return local_val
+
+    def __setattr__(self, name, value):
+        if name in _ModuleProxy.__slots__:
+            super(_ModuleProxy, self).__setattr__(name, value)
+            return
+        # Setting it deletes it from this module, so that
+        # we then continue to fall through to the original module.
+        try:
+            delattr(self._orig_mod, name)
+        except AttributeError:
+            pass
+
+        setattr(self.__get_stdlib_support(), name, value)
+
+# When is this not defined in test.support?
+HOSTv6 = _Default('::1')
+
+sys.modules[__name__] = _ModuleProxy()