first add files

18 files changed, 2364 insertions, 0 deletions

diff --git a/lib/greenlet/tests/__init__.py b/lib/greenlet/tests/__init__.py
new file mode 100644
index 0000000..e69de29
--- /dev/null
+++ b/lib/greenlet/tests/__init__.py
diff --git a/lib/greenlet/tests/_test_extension.c b/lib/greenlet/tests/_test_extension.c
new file mode 100644
index 0000000..4fe087d
--- /dev/null
+++ b/lib/greenlet/tests/_test_extension.c
@@ -0,0 +1,216 @@
+/* This is a set of functions used by test_extension_interface.py to test the
+ * Greenlet C API.
+ */
+
+#include "../greenlet.h"
+
+#ifndef Py_RETURN_NONE
+#    define Py_RETURN_NONE return Py_INCREF(Py_None), Py_None
+#endif
+
+#define TEST_MODULE_NAME "_test_extension"
+
+static PyObject*
+test_switch(PyObject* self, PyObject* greenlet)
+{
+    PyObject* result = NULL;
+
+    if (greenlet == NULL || !PyGreenlet_Check(greenlet)) {
+        PyErr_BadArgument();
+        return NULL;
+    }
+
+    result = PyGreenlet_Switch((PyGreenlet*)greenlet, NULL, NULL);
+    if (result == NULL) {
+        if (!PyErr_Occurred()) {
+            PyErr_SetString(PyExc_AssertionError,
+                            "greenlet.switch() failed for some reason.");
+        }
+        return NULL;
+    }
+    Py_INCREF(result);
+    return result;
+}
+
+static PyObject*
+test_switch_kwargs(PyObject* self, PyObject* args, PyObject* kwargs)
+{
+    PyGreenlet* g = NULL;
+    PyObject* result = NULL;
+
+    PyArg_ParseTuple(args, "O!", &PyGreenlet_Type, &g);
+
+    if (g == NULL || !PyGreenlet_Check(g)) {
+        PyErr_BadArgument();
+        return NULL;
+    }
+
+    result = PyGreenlet_Switch(g, NULL, kwargs);
+    if (result == NULL) {
+        if (!PyErr_Occurred()) {
+            PyErr_SetString(PyExc_AssertionError,
+                            "greenlet.switch() failed for some reason.");
+        }
+        return NULL;
+    }
+    Py_XINCREF(result);
+    return result;
+}
+
+static PyObject*
+test_getcurrent(PyObject* self)
+{
+    PyGreenlet* g = PyGreenlet_GetCurrent();
+    if (g == NULL || !PyGreenlet_Check(g) || !PyGreenlet_ACTIVE(g)) {
+        PyErr_SetString(PyExc_AssertionError,
+                        "getcurrent() returned an invalid greenlet");
+        Py_XDECREF(g);
+        return NULL;
+    }
+    Py_DECREF(g);
+    Py_RETURN_NONE;
+}
+
+static PyObject*
+test_setparent(PyObject* self, PyObject* arg)
+{
+    PyGreenlet* current;
+    PyGreenlet* greenlet = NULL;
+
+    if (arg == NULL || !PyGreenlet_Check(arg)) {
+        PyErr_BadArgument();
+        return NULL;
+    }
+    if ((current = PyGreenlet_GetCurrent()) == NULL) {
+        return NULL;
+    }
+    greenlet = (PyGreenlet*)arg;
+    if (PyGreenlet_SetParent(greenlet, current)) {
+        Py_DECREF(current);
+        return NULL;
+    }
+    Py_DECREF(current);
+    if (PyGreenlet_Switch(greenlet, NULL, NULL) == NULL) {
+        return NULL;
+    }
+    Py_RETURN_NONE;
+}
+
+static PyObject*
+test_new_greenlet(PyObject* self, PyObject* callable)
+{
+    PyObject* result = NULL;
+    PyGreenlet* greenlet = PyGreenlet_New(callable, NULL);
+
+    if (!greenlet) {
+        return NULL;
+    }
+
+    result = PyGreenlet_Switch(greenlet, NULL, NULL);
+    if (result == NULL) {
+        return NULL;
+    }
+
+    Py_INCREF(result);
+    return result;
+}
+
+static PyObject*
+test_raise_dead_greenlet(PyObject* self)
+{
+    PyErr_SetString(PyExc_GreenletExit, "test GreenletExit exception.");
+    return NULL;
+}
+
+static PyObject*
+test_raise_greenlet_error(PyObject* self)
+{
+    PyErr_SetString(PyExc_GreenletError, "test greenlet.error exception");
+    return NULL;
+}
+
+static PyObject*
+test_throw(PyObject* self, PyGreenlet* g)
+{
+    const char msg[] = "take that sucka!";
+    PyObject* msg_obj = Py_BuildValue("s", msg);
+    PyGreenlet_Throw(g, PyExc_ValueError, msg_obj, NULL);
+    Py_DECREF(msg_obj);
+    Py_RETURN_NONE;
+}
+
+static PyMethodDef test_methods[] = {
+    {"test_switch",
+     (PyCFunction)test_switch,
+     METH_O,
+     "Switch to the provided greenlet sending provided arguments, and \n"
+     "return the results."},
+    {"test_switch_kwargs",
+     (PyCFunction)test_switch_kwargs,
+     METH_VARARGS | METH_KEYWORDS,
+     "Switch to the provided greenlet sending the provided keyword args."},
+    {"test_getcurrent",
+     (PyCFunction)test_getcurrent,
+     METH_NOARGS,
+     "Test PyGreenlet_GetCurrent()"},
+    {"test_setparent",
+     (PyCFunction)test_setparent,
+     METH_O,
+     "Se the parent of the provided greenlet and switch to it."},
+    {"test_new_greenlet",
+     (PyCFunction)test_new_greenlet,
+     METH_O,
+     "Test PyGreenlet_New()"},
+    {"test_raise_dead_greenlet",
+     (PyCFunction)test_raise_dead_greenlet,
+     METH_NOARGS,
+     "Just raise greenlet.GreenletExit"},
+    {"test_raise_greenlet_error",
+     (PyCFunction)test_raise_greenlet_error,
+     METH_NOARGS,
+     "Just raise greenlet.error"},
+    {"test_throw",
+     (PyCFunction)test_throw,
+     METH_O,
+     "Throw a ValueError at the provided greenlet"},
+    {NULL, NULL, 0, NULL}};
+
+#if PY_MAJOR_VERSION >= 3
+#    define INITERROR return NULL
+
+static struct PyModuleDef moduledef = {PyModuleDef_HEAD_INIT,
+                                       TEST_MODULE_NAME,
+                                       NULL,
+                                       0,
+                                       test_methods,
+                                       NULL,
+                                       NULL,
+                                       NULL,
+                                       NULL};
+
+PyMODINIT_FUNC
+PyInit__test_extension(void)
+#else
+#    define INITERROR return
+PyMODINIT_FUNC
+init_test_extension(void)
+#endif
+{
+    PyObject* module = NULL;
+
+#if PY_MAJOR_VERSION >= 3
+    module = PyModule_Create(&moduledef);
+#else
+    module = Py_InitModule(TEST_MODULE_NAME, test_methods);
+#endif
+
+    if (module == NULL) {
+        INITERROR;
+    }
+
+    PyGreenlet_Import();
+
+#if PY_MAJOR_VERSION >= 3
+    return module;
+#endif
+}
diff --git a/lib/greenlet/tests/_test_extension.cpython-39-x86_64-linux-gnu.so b/lib/greenlet/tests/_test_extension.cpython-39-x86_64-linux-gnu.so
new file mode 100755
index 0000000..ea567a8
--- /dev/null
+++ b/lib/greenlet/tests/_test_extension.cpython-39-x86_64-linux-gnu.so
diff --git a/lib/greenlet/tests/_test_extension_cpp.cpp b/lib/greenlet/tests/_test_extension_cpp.cpp
new file mode 100644
index 0000000..72e3d81
--- /dev/null
+++ b/lib/greenlet/tests/_test_extension_cpp.cpp
@@ -0,0 +1,121 @@
+/* This is a set of functions used to test C++ exceptions are not
+ * broken during greenlet switches
+ */
+
+#include "../greenlet.h"
+
+struct exception_t {
+    int depth;
+    exception_t(int depth) : depth(depth) {}
+};
+
+/* Functions are called via pointers to prevent inlining */
+static void (*p_test_exception_throw)(int depth);
+static PyObject* (*p_test_exception_switch_recurse)(int depth, int left);
+
+static void
+test_exception_throw(int depth)
+{
+    throw exception_t(depth);
+}
+
+static PyObject*
+test_exception_switch_recurse(int depth, int left)
+{
+    if (left > 0) {
+        return p_test_exception_switch_recurse(depth, left - 1);
+    }
+
+    PyObject* result = NULL;
+    PyGreenlet* self = PyGreenlet_GetCurrent();
+    if (self == NULL)
+        return NULL;
+
+    try {
+        PyGreenlet_Switch(self->parent, NULL, NULL);
+        p_test_exception_throw(depth);
+        PyErr_SetString(PyExc_RuntimeError,
+                        "throwing C++ exception didn't work");
+    }
+    catch (exception_t& e) {
+        if (e.depth != depth)
+            PyErr_SetString(PyExc_AssertionError, "depth mismatch");
+        else
+            result = PyLong_FromLong(depth);
+    }
+    catch (...) {
+        PyErr_SetString(PyExc_RuntimeError, "unexpected C++ exception");
+    }
+
+    Py_DECREF(self);
+    return result;
+}
+
+/* test_exception_switch(int depth)
+ * - recurses depth times
+ * - switches to parent inside try/catch block
+ * - throws an exception that (expected to be caught in the same function)
+ * - verifies depth matches (exceptions shouldn't be caught in other greenlets)
+ */
+static PyObject*
+test_exception_switch(PyObject* self, PyObject* args)
+{
+    int depth;
+    if (!PyArg_ParseTuple(args, "i", &depth))
+        return NULL;
+    return p_test_exception_switch_recurse(depth, depth);
+}
+
+static PyMethodDef test_methods[] = {
+    {"test_exception_switch",
+     (PyCFunction)&test_exception_switch,
+     METH_VARARGS,
+     "Switches to parent twice, to test exception handling and greenlet "
+     "switching."},
+    {NULL, NULL, 0, NULL}};
+
+#if PY_MAJOR_VERSION >= 3
+#    define INITERROR return NULL
+
+static struct PyModuleDef moduledef = {PyModuleDef_HEAD_INIT,
+                                       "greenlet.tests._test_extension_cpp",
+                                       NULL,
+                                       0,
+                                       test_methods,
+                                       NULL,
+                                       NULL,
+                                       NULL,
+                                       NULL};
+
+PyMODINIT_FUNC
+PyInit__test_extension_cpp(void)
+#else
+#    define INITERROR return
+PyMODINIT_FUNC
+init_test_extension_cpp(void)
+#endif
+{
+    PyObject* module = NULL;
+
+#if PY_MAJOR_VERSION >= 3
+    module = PyModule_Create(&moduledef);
+#else
+    module = Py_InitModule("greenlet.tests._test_extension_cpp", test_methods);
+#endif
+
+    if (module == NULL) {
+        INITERROR;
+    }
+
+    PyGreenlet_Import();
+    if (_PyGreenlet_API == NULL) {
+        INITERROR;
+    }
+
+    p_test_exception_throw = test_exception_throw;
+    p_test_exception_switch_recurse = test_exception_switch_recurse;
+
+#if PY_MAJOR_VERSION >= 3
+    return module;
+#endif
+}
diff --git a/lib/greenlet/tests/_test_extension_cpp.cpython-39-x86_64-linux-gnu.so b/lib/greenlet/tests/_test_extension_cpp.cpython-39-x86_64-linux-gnu.so
new file mode 100755
index 0000000..0e50cfe
--- /dev/null
+++ b/lib/greenlet/tests/_test_extension_cpp.cpython-39-x86_64-linux-gnu.so
diff --git a/lib/greenlet/tests/test_contextvars.py b/lib/greenlet/tests/test_contextvars.py
new file mode 100644
index 0000000..49b7c0d
--- /dev/null
+++ b/lib/greenlet/tests/test_contextvars.py
@@ -0,0 +1,266 @@
+import unittest
+import gc
+import sys
+
+from functools import partial
+
+from greenlet import greenlet
+from greenlet import getcurrent
+
+
+try:
+    from contextvars import Context
+    from contextvars import ContextVar
+    from contextvars import copy_context
+except ImportError:
+    Context = ContextVar = copy_context = None
+
+# 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)
+
+    def _increment(self, greenlet_id, ctx_var, callback, counts, expect):
+        if expect is None:
+            self.assertIsNone(ctx_var.get())
+        else:
+            self.assertEqual(ctx_var.get(), expect)
+        ctx_var.set(greenlet_id)
+        for _ in range(2):
+            counts[ctx_var.get()] += 1
+            callback()
+
+    def _test_context(self, propagate_by):
+        id_var = ContextVar("id", default=None)
+        id_var.set(0)
+
+        callback = getcurrent().switch
+        counts = dict((i, 0) for i in range(5))
+
+        lets = [
+            greenlet(partial(
+                partial(
+                    copy_context().run,
+                    self._increment
+                ) if propagate_by == "run" else self._increment,
+                greenlet_id=i,
+                ctx_var=id_var,
+                callback=callback,
+                counts=counts,
+                expect=(
+                    i - 1 if propagate_by == "share" else
+                    0 if propagate_by in ("set", "run") else None
+                )
+            ))
+            for i in range(1, 5)
+        ]
+
+        for let in lets:
+            if propagate_by == "set":
+                let.gr_context = copy_context()
+            elif propagate_by == "share":
+                let.gr_context = getcurrent().gr_context
+
+        for i in range(2):
+            counts[id_var.get()] += 1
+            for let in lets:
+                let.switch()
+
+        if propagate_by == "run":
+            # Must leave each context.run() in reverse order of entry
+            for let in reversed(lets):
+                let.switch()
+        else:
+            # No context.run(), so fine to exit in any order.
+            for let in lets:
+                let.switch()
+
+        for let in lets:
+            self.assertTrue(let.dead)
+            # When using run(), we leave the run() as the greenlet dies,
+            # and there's no context "underneath". When not using run(),
+            # gr_context still reflects the context the greenlet was
+            # running in.
+            self.assertEqual(let.gr_context is None, propagate_by == "run")
+
+        if propagate_by == "share":
+            self.assertEqual(counts, {0: 1, 1: 1, 2: 1, 3: 1, 4: 6})
+        else:
+            self.assertEqual(set(counts.values()), set([2]))
+
+    def test_context_propagated_by_context_run(self):
+        self._new_ctx_run(self._test_context, "run")
+
+    def test_context_propagated_by_setting_attribute(self):
+        self._new_ctx_run(self._test_context, "set")
+
+    def test_context_not_propagated(self):
+        self._new_ctx_run(self._test_context, None)
+
+    def test_context_shared(self):
+        self._new_ctx_run(self._test_context, "share")
+
+    def test_break_ctxvars(self):
+        let1 = greenlet(copy_context().run)
+        let2 = greenlet(copy_context().run)
+        let1.switch(getcurrent().switch)
+        let2.switch(getcurrent().switch)
+        # Since let2 entered the current context and let1 exits its own, the
+        # interpreter emits:
+        # RuntimeError: cannot exit context: thread state references a different context object
+        let1.switch()
+
+    def test_not_broken_if_using_attribute_instead_of_context_run(self):
+        let1 = greenlet(getcurrent().switch)
+        let2 = greenlet(getcurrent().switch)
+        let1.gr_context = copy_context()
+        let2.gr_context = copy_context()
+        let1.switch()
+        let2.switch()
+        let1.switch()
+        let2.switch()
+
+    def test_context_assignment_while_running(self):
+        id_var = ContextVar("id", default=None)
+
+        def target():
+            self.assertIsNone(id_var.get())
+            self.assertIsNone(gr.gr_context)
+
+            # Context is created on first use
+            id_var.set(1)
+            self.assertIsInstance(gr.gr_context, Context)
+            self.assertEqual(id_var.get(), 1)
+            self.assertEqual(gr.gr_context[id_var], 1)
+
+            # Clearing the context makes it get re-created as another
+            # empty context when next used
+            old_context = gr.gr_context
+            gr.gr_context = None  # assign None while running
+            self.assertIsNone(id_var.get())
+            self.assertIsNone(gr.gr_context)
+            id_var.set(2)
+            self.assertIsInstance(gr.gr_context, Context)
+            self.assertEqual(id_var.get(), 2)
+            self.assertEqual(gr.gr_context[id_var], 2)
+
+            new_context = gr.gr_context
+            getcurrent().parent.switch((old_context, new_context))
+            # parent switches us back to old_context
+
+            self.assertEqual(id_var.get(), 1)
+            gr.gr_context = new_context  # assign non-None while running
+            self.assertEqual(id_var.get(), 2)
+
+            getcurrent().parent.switch()
+            # parent switches us back to no context
+            self.assertIsNone(id_var.get())
+            self.assertIsNone(gr.gr_context)
+            gr.gr_context = old_context
+            self.assertEqual(id_var.get(), 1)
+
+            getcurrent().parent.switch()
+            # parent switches us back to no context
+            self.assertIsNone(id_var.get())
+            self.assertIsNone(gr.gr_context)
+
+        gr = greenlet(target)
+
+        with self.assertRaisesRegex(AttributeError, "can't delete attr"):
+            del gr.gr_context
+
+        self.assertIsNone(gr.gr_context)
+        old_context, new_context = gr.switch()
+        self.assertIs(new_context, gr.gr_context)
+        self.assertEqual(old_context[id_var], 1)
+        self.assertEqual(new_context[id_var], 2)
+        self.assertEqual(new_context.run(id_var.get), 2)
+        gr.gr_context = old_context  # assign non-None while suspended
+        gr.switch()
+        self.assertIs(gr.gr_context, new_context)
+        gr.gr_context = None  # assign None while suspended
+        gr.switch()
+        self.assertIs(gr.gr_context, old_context)
+        gr.gr_context = None
+        gr.switch()
+        self.assertIsNone(gr.gr_context)
+
+        # Make sure there are no reference leaks
+        gr = None
+        gc.collect()
+        self.assertEqual(sys.getrefcount(old_context), 2)
+        self.assertEqual(sys.getrefcount(new_context), 2)
+
+    def test_context_assignment_different_thread(self):
+        import threading
+
+        ctx = Context()
+        var = ContextVar("var", default=None)
+        is_running = threading.Event()
+        should_suspend = threading.Event()
+        did_suspend = threading.Event()
+        should_exit = threading.Event()
+        holder = []
+
+        def greenlet_in_thread_fn():
+            var.set(1)
+            is_running.set()
+            should_suspend.wait()
+            var.set(2)
+            getcurrent().parent.switch()
+            holder.append(var.get())
+
+        def thread_fn():
+            gr = greenlet(greenlet_in_thread_fn)
+            gr.gr_context = ctx
+            holder.append(gr)
+            gr.switch()
+            did_suspend.set()
+            should_exit.wait()
+            gr.switch()
+
+        thread = threading.Thread(target=thread_fn, daemon=True)
+        thread.start()
+        is_running.wait()
+        gr = holder[0]
+
+        # Can't access or modify context if the greenlet is running
+        # in a different thread
+        with self.assertRaisesRegex(ValueError, "running in a different"):
+            getattr(gr, 'gr_context')
+        with self.assertRaisesRegex(ValueError, "running in a different"):
+            gr.gr_context = None
+
+        should_suspend.set()
+        did_suspend.wait()
+
+        # OK to access and modify context if greenlet is suspended
+        self.assertIs(gr.gr_context, ctx)
+        self.assertEqual(gr.gr_context[var], 2)
+        gr.gr_context = None
+
+        should_exit.set()
+        thread.join()
+
+        self.assertEqual(holder, [gr, None])
+
+        # Context can still be accessed/modified when greenlet is dead:
+        self.assertIsNone(gr.gr_context)
+        gr.gr_context = ctx
+        self.assertIs(gr.gr_context, ctx)
+
+@unittest.skipIf(Context is not None, "ContextVar supported")
+class NoContextVarsTests(unittest.TestCase):
+    def test_contextvars_errors(self):
+        let1 = greenlet(getcurrent().switch)
+        self.assertFalse(hasattr(let1, 'gr_context'))
+        with self.assertRaises(AttributeError):
+            getattr(let1, 'gr_context')
+        with self.assertRaises(AttributeError):
+            let1.gr_context = None
+        let1.switch()
+        with self.assertRaises(AttributeError):
+            getattr(let1, 'gr_context')
+        with self.assertRaises(AttributeError):
+            let1.gr_context = None
diff --git a/lib/greenlet/tests/test_cpp.py b/lib/greenlet/tests/test_cpp.py
new file mode 100644
index 0000000..741ea10
--- /dev/null
+++ b/lib/greenlet/tests/test_cpp.py
@@ -0,0 +1,18 @@
+from __future__ import print_function
+from __future__ import absolute_import
+
+import unittest
+
+import greenlet
+from . import _test_extension_cpp
+
+
+class CPPTests(unittest.TestCase):
+    def test_exception_switch(self):
+        greenlets = []
+        for i in range(4):
+            g = greenlet.greenlet(_test_extension_cpp.test_exception_switch)
+            g.switch(i)
+            greenlets.append(g)
+        for i, g in enumerate(greenlets):
+            self.assertEqual(g.switch(), i)
diff --git a/lib/greenlet/tests/test_extension_interface.py b/lib/greenlet/tests/test_extension_interface.py
new file mode 100644
index 0000000..a92ea1f
--- /dev/null
+++ b/lib/greenlet/tests/test_extension_interface.py
@@ -0,0 +1,77 @@
+from __future__ import print_function
+from __future__ import absolute_import
+
+import sys
+import unittest
+
+import greenlet
+from . import _test_extension
+
+
+class CAPITests(unittest.TestCase):
+    def test_switch(self):
+        self.assertEqual(
+            50, _test_extension.test_switch(greenlet.greenlet(lambda: 50)))
+
+    def test_switch_kwargs(self):
+        def foo(x, y):
+            return x * y
+        g = greenlet.greenlet(foo)
+        self.assertEqual(6, _test_extension.test_switch_kwargs(g, x=3, y=2))
+
+    def test_setparent(self):
+        def foo():
+            def bar():
+                greenlet.getcurrent().parent.switch()
+
+                # This final switch should go back to the main greenlet, since
+                # the test_setparent() function in the C extension should have
+                # reparented this greenlet.
+                greenlet.getcurrent().parent.switch()
+                raise AssertionError("Should never have reached this code")
+            child = greenlet.greenlet(bar)
+            child.switch()
+            greenlet.getcurrent().parent.switch(child)
+            greenlet.getcurrent().parent.throw(
+                AssertionError("Should never reach this code"))
+        foo_child = greenlet.greenlet(foo).switch()
+        self.assertEqual(None, _test_extension.test_setparent(foo_child))
+
+    def test_getcurrent(self):
+        _test_extension.test_getcurrent()
+
+    def test_new_greenlet(self):
+        self.assertEqual(-15, _test_extension.test_new_greenlet(lambda: -15))
+
+    def test_raise_greenlet_dead(self):
+        self.assertRaises(
+            greenlet.GreenletExit, _test_extension.test_raise_dead_greenlet)
+
+    def test_raise_greenlet_error(self):
+        self.assertRaises(
+            greenlet.error, _test_extension.test_raise_greenlet_error)
+
+    def test_throw(self):
+        seen = []
+
+        def foo():
+            try:
+                greenlet.getcurrent().parent.switch()
+            except ValueError:
+                seen.append(sys.exc_info()[1])
+            except greenlet.GreenletExit:
+                raise AssertionError
+        g = greenlet.greenlet(foo)
+        g.switch()
+        _test_extension.test_throw(g)
+        self.assertEqual(len(seen), 1)
+        self.assertTrue(
+            isinstance(seen[0], ValueError),
+            "ValueError was not raised in foo()")
+        self.assertEqual(
+            str(seen[0]),
+            'take that sucka!',
+            "message doesn't match")
+
+if __name__ == '__main__':
+    unittest.main()
diff --git a/lib/greenlet/tests/test_gc.py b/lib/greenlet/tests/test_gc.py
new file mode 100644
index 0000000..a2a41ca
--- /dev/null
+++ b/lib/greenlet/tests/test_gc.py
@@ -0,0 +1,77 @@
+import gc
+import sys
+import unittest
+import weakref
+
+import greenlet
+
+
+class GCTests(unittest.TestCase):
+    def test_dead_circular_ref(self):
+        o = weakref.ref(greenlet.greenlet(greenlet.getcurrent).switch())
+        gc.collect()
+        self.assertTrue(o() is None)
+        self.assertFalse(gc.garbage, gc.garbage)
+
+    if greenlet.GREENLET_USE_GC:
+        # These only work with greenlet gc support
+
+        def test_circular_greenlet(self):
+            class circular_greenlet(greenlet.greenlet):
+                pass
+            o = circular_greenlet()
+            o.self = o
+            o = weakref.ref(o)
+            gc.collect()
+            self.assertTrue(o() is None)
+            self.assertFalse(gc.garbage, gc.garbage)
+
+        def test_inactive_ref(self):
+            class inactive_greenlet(greenlet.greenlet):
+                def __init__(self):
+                    greenlet.greenlet.__init__(self, run=self.run)
+
+                def run(self):
+                    pass
+            o = inactive_greenlet()
+            o = weakref.ref(o)
+            gc.collect()
+            self.assertTrue(o() is None)
+            self.assertFalse(gc.garbage, gc.garbage)
+
+        def test_finalizer_crash(self):
+            # This test is designed to crash when active greenlets
+            # are made garbage collectable, until the underlying
+            # problem is resolved. How does it work:
+            # - order of object creation is important
+            # - array is created first, so it is moved to unreachable first
+            # - we create a cycle between a greenlet and this array
+            # - we create an object that participates in gc, is only
+            #   referenced by a greenlet, and would corrupt gc lists
+            #   on destruction, the easiest is to use an object with
+            #   a finalizer
+            # - because array is the first object in unreachable it is
+            #   cleared first, which causes all references to greenlet
+            #   to disappear and causes greenlet to be destroyed, but since
+            #   it is still live it causes a switch during gc, which causes
+            #   an object with finalizer to be destroyed, which causes stack
+            #   corruption and then a crash
+            class object_with_finalizer(object):
+                def __del__(self):
+                    pass
+            array = []
+            parent = greenlet.getcurrent()
+            def greenlet_body():
+                greenlet.getcurrent().object = object_with_finalizer()
+                try:
+                    parent.switch()
+                finally:
+                    del greenlet.getcurrent().object
+            g = greenlet.greenlet(greenlet_body)
+            g.array = array
+            array.append(g)
+            g.switch()
+            del array
+            del g
+            greenlet.getcurrent()
+            gc.collect()
diff --git a/lib/greenlet/tests/test_generator.py b/lib/greenlet/tests/test_generator.py
new file mode 100644
index 0000000..62f9f26
--- /dev/null
+++ b/lib/greenlet/tests/test_generator.py
@@ -0,0 +1,59 @@
+import unittest
+from greenlet import greenlet
+
+
+class genlet(greenlet):
+
+    def __init__(self, *args, **kwds):
+        self.args = args
+        self.kwds = kwds
+
+    def run(self):
+        fn, = self.fn
+        fn(*self.args, **self.kwds)
+
+    def __iter__(self):
+        return self
+
+    def __next__(self):
+        self.parent = greenlet.getcurrent()
+        result = self.switch()
+        if self:
+            return result
+        else:
+            raise StopIteration
+
+    # Hack: Python < 2.6 compatibility
+    next = __next__
+
+
+def Yield(value):
+    g = greenlet.getcurrent()
+    while not isinstance(g, genlet):
+        if g is None:
+            raise RuntimeError('yield outside a genlet')
+        g = g.parent
+    g.parent.switch(value)
+
+
+def generator(func):
+    class generator(genlet):
+        fn = (func,)
+    return generator
+
+# ____________________________________________________________
+
+
+class GeneratorTests(unittest.TestCase):
+    def test_generator(self):
+        seen = []
+
+        def g(n):
+            for i in range(n):
+                seen.append(i)
+                Yield(i)
+        g = generator(g)
+        for k in range(3):
+            for j in g(5):
+                seen.append(j)
+        self.assertEqual(seen, 3 * [0, 0, 1, 1, 2, 2, 3, 3, 4, 4])
diff --git a/lib/greenlet/tests/test_generator_nested.py b/lib/greenlet/tests/test_generator_nested.py
new file mode 100644
index 0000000..6b4f023
--- /dev/null
+++ b/lib/greenlet/tests/test_generator_nested.py
@@ -0,0 +1,165 @@
+import unittest
+from greenlet import greenlet
+
+
+class genlet(greenlet):
+
+    def __init__(self, *args, **kwds):
+        self.args = args
+        self.kwds = kwds
+        self.child = None
+
+    def run(self):
+        fn, = self.fn
+        fn(*self.args, **self.kwds)
+
+    def __iter__(self):
+        return self
+
+    def set_child(self, child):
+        self.child = child
+
+    def __next__(self):
+        if self.child:
+            child = self.child
+            while child.child:
+                tmp = child
+                child = child.child
+                tmp.child = None
+
+            result = child.switch()
+        else:
+            self.parent = greenlet.getcurrent()
+            result = self.switch()
+
+        if self:
+            return result
+        else:
+            raise StopIteration
+
+    # Hack: Python < 2.6 compatibility
+    next = __next__
+
+
+def Yield(value, level=1):
+    g = greenlet.getcurrent()
+
+    while level != 0:
+        if not isinstance(g, genlet):
+            raise RuntimeError('yield outside a genlet')
+        if level > 1:
+            g.parent.set_child(g)
+        g = g.parent
+        level -= 1
+
+    g.switch(value)
+
+
+def Genlet(func):
+    class Genlet(genlet):
+        fn = (func,)
+    return Genlet
+
+# ____________________________________________________________
+
+
+def g1(n, seen):
+    for i in range(n):
+        seen.append(i + 1)
+        yield i
+
+
+def g2(n, seen):
+    for i in range(n):
+        seen.append(i + 1)
+        Yield(i)
+
+g2 = Genlet(g2)
+
+
+def nested(i):
+    Yield(i)
+
+
+def g3(n, seen):
+    for i in range(n):
+        seen.append(i + 1)
+        nested(i)
+g3 = Genlet(g3)
+
+
+def a(n):
+    if n == 0:
+        return
+    for ii in ax(n - 1):
+        Yield(ii)
+    Yield(n)
+ax = Genlet(a)
+
+
+def perms(l):
+    if len(l) > 1:
+        for e in l:
+            # No syntactical sugar for generator expressions
+            [Yield([e] + p) for p in perms([x for x in l if x != e])]
+    else:
+        Yield(l)
+perms = Genlet(perms)
+
+
+def gr1(n):
+    for ii in range(1, n):
+        Yield(ii)
+        Yield(ii * ii, 2)
+
+gr1 = Genlet(gr1)
+
+
+def gr2(n, seen):
+    for ii in gr1(n):
+        seen.append(ii)
+
+gr2 = Genlet(gr2)
+
+
+class NestedGeneratorTests(unittest.TestCase):
+    def test_layered_genlets(self):
+        seen = []
+        for ii in gr2(5, seen):
+            seen.append(ii)
+        self.assertEqual(seen, [1, 1, 2, 4, 3, 9, 4, 16])
+
+    def test_permutations(self):
+        gen_perms = perms(list(range(4)))
+        permutations = list(gen_perms)
+        self.assertEqual(len(permutations), 4 * 3 * 2 * 1)
+        self.assertTrue([0, 1, 2, 3] in permutations)
+        self.assertTrue([3, 2, 1, 0] in permutations)
+        res = []
+        for ii in zip(perms(list(range(4))), perms(list(range(3)))):
+            res.append(ii)
+        self.assertEqual(
+            res,
+            [([0, 1, 2, 3], [0, 1, 2]), ([0, 1, 3, 2], [0, 2, 1]),
+             ([0, 2, 1, 3], [1, 0, 2]), ([0, 2, 3, 1], [1, 2, 0]),
+             ([0, 3, 1, 2], [2, 0, 1]), ([0, 3, 2, 1], [2, 1, 0])])
+        # XXX Test to make sure we are working as a generator expression
+
+    def test_genlet_simple(self):
+        for g in [g1, g2, g3]:
+            seen = []
+            for k in range(3):
+                for j in g(5, seen):
+                    seen.append(j)
+            self.assertEqual(seen, 3 * [1, 0, 2, 1, 3, 2, 4, 3, 5, 4])
+
+    def test_genlet_bad(self):
+        try:
+            Yield(10)
+        except RuntimeError:
+            pass
+
+    def test_nested_genlets(self):
+        seen = []
+        for ii in ax(5):
+            seen.append(ii)
diff --git a/lib/greenlet/tests/test_greenlet.py b/lib/greenlet/tests/test_greenlet.py
new file mode 100644
index 0000000..5509a8b
--- /dev/null
+++ b/lib/greenlet/tests/test_greenlet.py
@@ -0,0 +1,728 @@
+import gc
+import sys
+import time
+import threading
+import unittest
+from abc import ABCMeta, abstractmethod
+
+from greenlet import greenlet
+
+# We manually manage locks in many tests
+# pylint:disable=consider-using-with
+
+class SomeError(Exception):
+    pass
+
+
+def fmain(seen):
+    try:
+        greenlet.getcurrent().parent.switch()
+    except:
+        seen.append(sys.exc_info()[0])
+        raise
+    raise SomeError
+
+
+def send_exception(g, exc):
+    # note: send_exception(g, exc)  can be now done with  g.throw(exc).
+    # the purpose of this test is to explicitely check the propagation rules.
+    def crasher(exc):
+        raise exc
+    g1 = greenlet(crasher, parent=g)
+    g1.switch(exc)
+
+
+class TestGreenlet(unittest.TestCase):
+    def test_simple(self):
+        lst = []
+
+        def f():
+            lst.append(1)
+            greenlet.getcurrent().parent.switch()
+            lst.append(3)
+        g = greenlet(f)
+        lst.append(0)
+        g.switch()
+        lst.append(2)
+        g.switch()
+        lst.append(4)
+        self.assertEqual(lst, list(range(5)))
+
+    def test_parent_equals_None(self):
+        g = greenlet(parent=None)
+        self.assertIsNotNone(g)
+        self.assertIs(g.parent, greenlet.getcurrent())
+
+    def test_run_equals_None(self):
+        g = greenlet(run=None)
+        self.assertIsNotNone(g)
+        self.assertIsNone(g.run)
+
+    def test_two_children(self):
+        lst = []
+
+        def f():
+            lst.append(1)
+            greenlet.getcurrent().parent.switch()
+            lst.extend([1, 1])
+        g = greenlet(f)
+        h = greenlet(f)
+        g.switch()
+        self.assertEqual(len(lst), 1)
+        h.switch()
+        self.assertEqual(len(lst), 2)
+        h.switch()
+        self.assertEqual(len(lst), 4)
+        self.assertEqual(h.dead, True)
+        g.switch()
+        self.assertEqual(len(lst), 6)
+        self.assertEqual(g.dead, True)
+
+    def test_two_recursive_children(self):
+        lst = []
+
+        def f():
+            lst.append(1)
+            greenlet.getcurrent().parent.switch()
+
+        def g():
+            lst.append(1)
+            g = greenlet(f)
+            g.switch()
+            lst.append(1)
+        g = greenlet(g)
+        g.switch()
+        self.assertEqual(len(lst), 3)
+        self.assertEqual(sys.getrefcount(g), 2)
+
+    def test_threads(self):
+        success = []
+
+        def f():
+            self.test_simple()
+            success.append(True)
+        ths = [threading.Thread(target=f) for i in range(10)]
+        for th in ths:
+            th.start()
+        for th in ths:
+            th.join()
+        self.assertEqual(len(success), len(ths))
+
+    def test_exception(self):
+        seen = []
+        g1 = greenlet(fmain)
+        g2 = greenlet(fmain)
+        g1.switch(seen)
+        g2.switch(seen)
+        g2.parent = g1
+        self.assertEqual(seen, [])
+        self.assertRaises(SomeError, g2.switch)
+        self.assertEqual(seen, [SomeError])
+        g2.switch()
+        self.assertEqual(seen, [SomeError])
+
+    def test_send_exception(self):
+        seen = []
+        g1 = greenlet(fmain)
+        g1.switch(seen)
+        self.assertRaises(KeyError, send_exception, g1, KeyError)
+        self.assertEqual(seen, [KeyError])
+
+    def test_dealloc(self):
+        seen = []
+        g1 = greenlet(fmain)
+        g2 = greenlet(fmain)
+        g1.switch(seen)
+        g2.switch(seen)
+        self.assertEqual(seen, [])
+        del g1
+        gc.collect()
+        self.assertEqual(seen, [greenlet.GreenletExit])
+        del g2
+        gc.collect()
+        self.assertEqual(seen, [greenlet.GreenletExit, greenlet.GreenletExit])
+
+    def test_dealloc_other_thread(self):
+        seen = []
+        someref = []
+        lock = threading.Lock()
+        lock.acquire()
+        lock2 = threading.Lock()
+        lock2.acquire()
+
+        def f():
+            g1 = greenlet(fmain)
+            g1.switch(seen)
+            someref.append(g1)
+            del g1
+            gc.collect()
+            lock.release()
+            lock2.acquire()
+            greenlet()   # trigger release
+            lock.release()
+            lock2.acquire()
+        t = threading.Thread(target=f)
+        t.start()
+        lock.acquire()
+        self.assertEqual(seen, [])
+        self.assertEqual(len(someref), 1)
+        del someref[:]
+        gc.collect()
+        # g1 is not released immediately because it's from another thread
+        self.assertEqual(seen, [])
+        lock2.release()
+        lock.acquire()
+        self.assertEqual(seen, [greenlet.GreenletExit])
+        lock2.release()
+        t.join()
+
+    def test_frame(self):
+        def f1():
+            f = sys._getframe(0) # pylint:disable=protected-access
+            self.assertEqual(f.f_back, None)
+            greenlet.getcurrent().parent.switch(f)
+            return "meaning of life"
+        g = greenlet(f1)
+        frame = g.switch()
+        self.assertTrue(frame is g.gr_frame)
+        self.assertTrue(g)
+
+        from_g = g.switch()
+        self.assertFalse(g)
+        self.assertEqual(from_g, 'meaning of life')
+        self.assertEqual(g.gr_frame, None)
+
+    def test_thread_bug(self):
+        def runner(x):
+            g = greenlet(lambda: time.sleep(x))
+            g.switch()
+        t1 = threading.Thread(target=runner, args=(0.2,))
+        t2 = threading.Thread(target=runner, args=(0.3,))
+        t1.start()
+        t2.start()
+        t1.join()
+        t2.join()
+
+    def test_switch_kwargs(self):
+        def run(a, b):
+            self.assertEqual(a, 4)
+            self.assertEqual(b, 2)
+            return 42
+        x = greenlet(run).switch(a=4, b=2)
+        self.assertEqual(x, 42)
+
+    def test_switch_kwargs_to_parent(self):
+        def run(x):
+            greenlet.getcurrent().parent.switch(x=x)
+            greenlet.getcurrent().parent.switch(2, x=3)
+            return x, x ** 2
+        g = greenlet(run)
+        self.assertEqual({'x': 3}, g.switch(3))
+        self.assertEqual(((2,), {'x': 3}), g.switch())
+        self.assertEqual((3, 9), g.switch())
+
+    def test_switch_to_another_thread(self):
+        data = {}
+        error = None
+        created_event = threading.Event()
+        done_event = threading.Event()
+
+        def run():
+            data['g'] = greenlet(lambda: None)
+            created_event.set()
+            done_event.wait()
+        thread = threading.Thread(target=run)
+        thread.start()
+        created_event.wait()
+        try:
+            data['g'].switch()
+        except greenlet.error:
+            error = sys.exc_info()[1]
+        self.assertIsNotNone(error, "greenlet.error was not raised!")
+        done_event.set()
+        thread.join()
+
+    def test_exc_state(self):
+        def f():
+            try:
+                raise ValueError('fun')
+            except: # pylint:disable=bare-except
+                exc_info = sys.exc_info()
+                greenlet(h).switch()
+                self.assertEqual(exc_info, sys.exc_info())
+
+        def h():
+            self.assertEqual(sys.exc_info(), (None, None, None))
+
+        greenlet(f).switch()
+
+    def test_instance_dict(self):
+        def f():
+            greenlet.getcurrent().test = 42
+        def deldict(g):
+            del g.__dict__
+        def setdict(g, value):
+            g.__dict__ = value
+        g = greenlet(f)
+        self.assertEqual(g.__dict__, {})
+        g.switch()
+        self.assertEqual(g.test, 42)
+        self.assertEqual(g.__dict__, {'test': 42})
+        g.__dict__ = g.__dict__
+        self.assertEqual(g.__dict__, {'test': 42})
+        self.assertRaises(TypeError, deldict, g)
+        self.assertRaises(TypeError, setdict, g, 42)
+
+    def test_threaded_reparent(self):
+        data = {}
+        created_event = threading.Event()
+        done_event = threading.Event()
+
+        def run():
+            data['g'] = greenlet(lambda: None)
+            created_event.set()
+            done_event.wait()
+
+        def blank():
+            greenlet.getcurrent().parent.switch()
+
+        def setparent(g, value):
+            g.parent = value
+
+        thread = threading.Thread(target=run)
+        thread.start()
+        created_event.wait()
+        g = greenlet(blank)
+        g.switch()
+        self.assertRaises(ValueError, setparent, g, data['g'])
+        done_event.set()
+        thread.join()
+
+    def test_deepcopy(self):
+        import copy
+        self.assertRaises(TypeError, copy.copy, greenlet())
+        self.assertRaises(TypeError, copy.deepcopy, greenlet())
+
+    def test_parent_restored_on_kill(self):
+        hub = greenlet(lambda: None)
+        main = greenlet.getcurrent()
+        result = []
+        def worker():
+            try:
+                # Wait to be killed
+                main.switch()
+            except greenlet.GreenletExit:
+                # Resurrect and switch to parent
+                result.append(greenlet.getcurrent().parent)
+                result.append(greenlet.getcurrent())
+                hub.switch()
+        g = greenlet(worker, parent=hub)
+        g.switch()
+        del g
+        self.assertTrue(result)
+        self.assertEqual(result[0], main)
+        self.assertEqual(result[1].parent, hub)
+
+    def test_parent_return_failure(self):
+        # No run causes AttributeError on switch
+        g1 = greenlet()
+        # Greenlet that implicitly switches to parent
+        g2 = greenlet(lambda: None, parent=g1)
+        # AttributeError should propagate to us, no fatal errors
+        self.assertRaises(AttributeError, g2.switch)
+
+    def test_throw_exception_not_lost(self):
+        class mygreenlet(greenlet):
+            def __getattribute__(self, name):
+                try:
+                    raise Exception()
+                except: # pylint:disable=bare-except
+                    pass
+                return greenlet.__getattribute__(self, name)
+        g = mygreenlet(lambda: None)
+        self.assertRaises(SomeError, g.throw, SomeError())
+
+    def test_throw_doesnt_crash(self):
+        result = []
+        def worker():
+            greenlet.getcurrent().parent.switch()
+        def creator():
+            g = greenlet(worker)
+            g.switch()
+            result.append(g)
+        t = threading.Thread(target=creator)
+        t.start()
+        t.join()
+        self.assertRaises(greenlet.error, result[0].throw, SomeError())
+
+    def test_recursive_startup(self):
+        class convoluted(greenlet):
+            def __init__(self):
+                greenlet.__init__(self)
+                self.count = 0
+            def __getattribute__(self, name):
+                if name == 'run' and self.count == 0:
+                    self.count = 1
+                    self.switch(43)
+                return greenlet.__getattribute__(self, name)
+            def run(self, value):
+                while True:
+                    self.parent.switch(value)
+        g = convoluted()
+        self.assertEqual(g.switch(42), 43)
+
+    def test_unexpected_reparenting(self):
+        another = []
+        def worker():
+            g = greenlet(lambda: None)
+            another.append(g)
+            g.switch()
+        t = threading.Thread(target=worker)
+        t.start()
+        t.join()
+        class convoluted(greenlet):
+            def __getattribute__(self, name):
+                if name == 'run':
+                    self.parent = another[0] # pylint:disable=attribute-defined-outside-init
+                return greenlet.__getattribute__(self, name)
+        g = convoluted(lambda: None)
+        self.assertRaises(greenlet.error, g.switch)
+
+    def test_threaded_updatecurrent(self):
+        # released when main thread should execute
+        lock1 = threading.Lock()
+        lock1.acquire()
+        # released when another thread should execute
+        lock2 = threading.Lock()
+        lock2.acquire()
+        class finalized(object):
+            def __del__(self):
+                # happens while in green_updatecurrent() in main greenlet
+                # should be very careful not to accidentally call it again
+                # at the same time we must make sure another thread executes
+                lock2.release()
+                lock1.acquire()
+                # now ts_current belongs to another thread
+        def deallocator():
+            greenlet.getcurrent().parent.switch()
+        def fthread():
+            lock2.acquire()
+            greenlet.getcurrent()
+            del g[0]
+            lock1.release()
+            lock2.acquire()
+            greenlet.getcurrent()
+            lock1.release()
+        main = greenlet.getcurrent()
+        g = [greenlet(deallocator)]
+        g[0].bomb = finalized()
+        g[0].switch()
+        t = threading.Thread(target=fthread)
+        t.start()
+        # let another thread grab ts_current and deallocate g[0]
+        lock2.release()
+        lock1.acquire()
+        # this is the corner stone
+        # getcurrent() will notice that ts_current belongs to another thread
+        # and start the update process, which would notice that g[0] should
+        # be deallocated, and that will execute an object's finalizer. Now,
+        # that object will let another thread run so it can grab ts_current
+        # again, which would likely crash the interpreter if there's no
+        # check for this case at the end of green_updatecurrent(). This test
+        # passes if getcurrent() returns correct result, but it's likely
+        # to randomly crash if it's not anyway.
+        self.assertEqual(greenlet.getcurrent(), main)
+        # wait for another thread to complete, just in case
+        t.join()
+
+    def test_dealloc_switch_args_not_lost(self):
+        seen = []
+        def worker():
+            # wait for the value
+            value = greenlet.getcurrent().parent.switch()
+            # delete all references to ourself
+            del worker[0]
+            initiator.parent = greenlet.getcurrent().parent
+            # switch to main with the value, but because
+            # ts_current is the last reference to us we
+            # return immediately
+            try:
+                greenlet.getcurrent().parent.switch(value)
+            finally:
+                seen.append(greenlet.getcurrent())
+        def initiator():
+            return 42 # implicitly falls thru to parent
+        worker = [greenlet(worker)]
+        worker[0].switch() # prime worker
+        initiator = greenlet(initiator, worker[0])
+        value = initiator.switch()
+        self.assertTrue(seen)
+        self.assertEqual(value, 42)
+
+
+
+    def test_tuple_subclass(self):
+        if sys.version_info[0] > 2:
+            # There's no apply in Python 3.x
+            def _apply(func, a, k):
+                func(*a, **k)
+        else:
+            _apply = apply # pylint:disable=undefined-variable
+
+        class mytuple(tuple):
+            def __len__(self):
+                greenlet.getcurrent().switch()
+                return tuple.__len__(self)
+        args = mytuple()
+        kwargs = dict(a=42)
+        def switchapply():
+            _apply(greenlet.getcurrent().parent.switch, args, kwargs)
+        g = greenlet(switchapply)
+        self.assertEqual(g.switch(), kwargs)
+
+    def test_abstract_subclasses(self):
+        AbstractSubclass = ABCMeta(
+            'AbstractSubclass',
+            (greenlet,),
+            {'run': abstractmethod(lambda self: None)})
+
+        class BadSubclass(AbstractSubclass):
+            pass
+
+        class GoodSubclass(AbstractSubclass):
+            def run(self):
+                pass
+
+        GoodSubclass() # should not raise
+        self.assertRaises(TypeError, BadSubclass)
+
+    def test_implicit_parent_with_threads(self):
+        if not gc.isenabled():
+            return # cannot test with disabled gc
+        N = gc.get_threshold()[0]
+        if N < 50:
+            return # cannot test with such a small N
+        def attempt():
+            lock1 = threading.Lock()
+            lock1.acquire()
+            lock2 = threading.Lock()
+            lock2.acquire()
+            recycled = [False]
+            def another_thread():
+                lock1.acquire() # wait for gc
+                greenlet.getcurrent() # update ts_current
+                lock2.release() # release gc
+            t = threading.Thread(target=another_thread)
+            t.start()
+            class gc_callback(object):
+                def __del__(self):
+                    lock1.release()
+                    lock2.acquire()
+                    recycled[0] = True
+            class garbage(object):
+                def __init__(self):
+                    self.cycle = self
+                    self.callback = gc_callback()
+            l = []
+            x = range(N*2)
+            current = greenlet.getcurrent()
+            g = garbage()
+            for _ in x:
+                g = None # lose reference to garbage
+                if recycled[0]:
+                    # gc callback called prematurely
+                    t.join()
+                    return False
+                last = greenlet()
+                if recycled[0]:
+                    break # yes! gc called in green_new
+                l.append(last) # increase allocation counter
+            else:
+                # gc callback not called when expected
+                gc.collect()
+                if recycled[0]:
+                    t.join()
+                return False
+            self.assertEqual(last.parent, current)
+            for g in l:
+                self.assertEqual(g.parent, current)
+            return True
+        for _ in range(5):
+            if attempt():
+                break
+
+    def test_issue_245_reference_counting_subclass_no_threads(self):
+        # https://github.com/python-greenlet/greenlet/issues/245
+        # Before the fix, this crashed pretty reliably on
+        # Python 3.10, at least on macOS; but much less reliably on other
+        # interpreters (memory layout must have changed).
+        # The threaded test crashed more reliably on more interpreters.
+        from greenlet import getcurrent
+        from greenlet import GreenletExit
+
+        class Greenlet(greenlet):
+            pass
+
+        initial_refs = sys.getrefcount(Greenlet)
+        # This has to be an instance variable because
+        # Python 2 raises a SyntaxError if we delete a local
+        # variable referenced in an inner scope.
+        self.glets = [] # pylint:disable=attribute-defined-outside-init
+
+        def greenlet_main():
+            try:
+                getcurrent().parent.switch()
+            except GreenletExit:
+                self.glets.append(getcurrent())
+
+        # Before the
+        for _ in range(10):
+            Greenlet(greenlet_main).switch()
+
+        del self.glets
+        self.assertEqual(sys.getrefcount(Greenlet), initial_refs)
+
+    def test_issue_245_reference_counting_subclass_threads(self):
+        # https://github.com/python-greenlet/greenlet/issues/245
+        from threading import Thread
+        from threading import Event
+
+        from greenlet import getcurrent
+
+        class MyGreenlet(greenlet):
+            pass
+
+        glets = []
+        ref_cleared = Event()
+
+        def greenlet_main():
+            getcurrent().parent.switch()
+
+        def thread_main(greenlet_running_event):
+            mine = MyGreenlet(greenlet_main)
+            glets.append(mine)
+            # The greenlets being deleted must be active
+            mine.switch()
+            # Don't keep any reference to it in this thread
+            del mine
+            # Let main know we published our greenlet.
+            greenlet_running_event.set()
+            # Wait for main to let us know the references are
+            # gone and the greenlet objects no longer reachable
+            ref_cleared.wait()
+            # The creating thread must call getcurrent() (or a few other
+            # greenlet APIs) because that's when the thread-local list of dead
+            # greenlets gets cleared.
+            getcurrent()
+
+        # We start with 3 references to the subclass:
+        # - This module
+        # - Its __mro__
+        # - The __subclassess__ attribute of greenlet
+        # - (If we call gc.get_referents(), we find four entries, including
+        #   some other tuple ``(greenlet)`` that I'm not sure about but must be part
+        #   of the machinery.)
+        #
+        # On Python 3.10 it's often enough to just run 3 threads; on Python 2.7,
+        # more threads are needed, and the results are still
+        # non-deterministic. Presumably the memory layouts are different
+        initial_refs = sys.getrefcount(MyGreenlet)
+        thread_ready_events = []
+        for _ in range(
+                initial_refs + 45
+        ):
+            event = Event()
+            thread = Thread(target=thread_main, args=(event,))
+            thread_ready_events.append(event)
+            thread.start()
+
+
+        for done_event in thread_ready_events:
+            done_event.wait()
+
+
+        del glets[:]
+        ref_cleared.set()
+        # Let any other thread run; it will crash the interpreter
+        # if not fixed (or silently corrupt memory and we possibly crash
+        # later).
+        time.sleep(1)
+        self.assertEqual(sys.getrefcount(MyGreenlet), initial_refs)
+
+
+class TestRepr(unittest.TestCase):
+
+    def assertEndsWith(self, got, suffix):
+        self.assertTrue(got.endswith(suffix), (got, suffix))
+
+    def test_main_while_running(self):
+        r = repr(greenlet.getcurrent())
+        self.assertEndsWith(r, " current active started main>")
+
+    def test_main_in_background(self):
+        main = greenlet.getcurrent()
+        def run():
+            return repr(main)
+
+        g = greenlet(run)
+        r = g.switch()
+        self.assertEndsWith(r, ' suspended active started main>')
+
+    def test_initial(self):
+        r = repr(greenlet())
+        self.assertEndsWith(r, ' pending>')
+
+    def test_main_from_other_thread(self):
+        main = greenlet.getcurrent()
+
+        class T(threading.Thread):
+            original_main = thread_main = None
+            main_glet = None
+            def run(self):
+                self.original_main = repr(main)
+                self.main_glet = greenlet.getcurrent()
+                self.thread_main = repr(self.main_glet)
+
+        t = T()
+        t.start()
+        t.join(10)
+
+        self.assertEndsWith(t.original_main, ' suspended active started main>')
+        self.assertEndsWith(t.thread_main, ' current active started main>')
+
+        r = repr(t.main_glet)
+        # main greenlets, even from dead threads, never really appear dead
+        # TODO: Can we find a better way to differentiate that?
+        assert not t.main_glet.dead
+        self.assertEndsWith(r, ' suspended active started main>')
+
+    def test_dead(self):
+        g = greenlet(lambda: None)
+        g.switch()
+        self.assertEndsWith(repr(g), ' dead>')
+        self.assertNotIn('suspended', repr(g))
+        self.assertNotIn('started', repr(g))
+        self.assertNotIn('active', repr(g))
+
+    def test_formatting_produces_native_str(self):
+        # https://github.com/python-greenlet/greenlet/issues/218
+        # %s formatting on Python 2 was producing unicode, not str.
+
+        g_dead = greenlet(lambda: None)
+        g_not_started = greenlet(lambda: None)
+        g_cur = greenlet.getcurrent()
+
+        for g in g_dead, g_not_started, g_cur:
+
+            self.assertIsInstance(
+                '%s' % (g,),
+                str
+            )
+            self.assertIsInstance(
+                '%r' % (g,),
+                str,
+            )
+
+
+if __name__ == '__main__':
+    unittest.main()
diff --git a/lib/greenlet/tests/test_leaks.py b/lib/greenlet/tests/test_leaks.py
new file mode 100644
index 0000000..2b02bfd
--- /dev/null
+++ b/lib/greenlet/tests/test_leaks.py
@@ -0,0 +1,178 @@
+import unittest
+import sys
+import gc
+
+import time
+import weakref
+import threading
+
+import greenlet
+
+class TestLeaks(unittest.TestCase):
+
+    def test_arg_refs(self):
+        args = ('a', 'b', 'c')
+        refcount_before = sys.getrefcount(args)
+        # pylint:disable=unnecessary-lambda
+        g = greenlet.greenlet(
+            lambda *args: greenlet.getcurrent().parent.switch(*args))
+        for _ in range(100):
+            g.switch(*args)
+        self.assertEqual(sys.getrefcount(args), refcount_before)
+
+    def test_kwarg_refs(self):
+        kwargs = {}
+        # pylint:disable=unnecessary-lambda
+        g = greenlet.greenlet(
+            lambda **kwargs: greenlet.getcurrent().parent.switch(**kwargs))
+        for _ in range(100):
+            g.switch(**kwargs)
+        self.assertEqual(sys.getrefcount(kwargs), 2)
+
+    assert greenlet.GREENLET_USE_GC # Option to disable this was removed in 1.0
+
+    def recycle_threads(self):
+        # By introducing a thread that does sleep we allow other threads,
+        # that have triggered their __block condition, but did not have a
+        # chance to deallocate their thread state yet, to finally do so.
+        # The way it works is by requiring a GIL switch (different thread),
+        # which does a GIL release (sleep), which might do a GIL switch
+        # to finished threads and allow them to clean up.
+        def worker():
+            time.sleep(0.001)
+        t = threading.Thread(target=worker)
+        t.start()
+        time.sleep(0.001)
+        t.join()
+
+    def test_threaded_leak(self):
+        gg = []
+        def worker():
+            # only main greenlet present
+            gg.append(weakref.ref(greenlet.getcurrent()))
+        for _ in range(2):
+            t = threading.Thread(target=worker)
+            t.start()
+            t.join()
+            del t
+        greenlet.getcurrent() # update ts_current
+        self.recycle_threads()
+        greenlet.getcurrent() # update ts_current
+        gc.collect()
+        greenlet.getcurrent() # update ts_current
+        for g in gg:
+            self.assertIsNone(g())
+
+    def test_threaded_adv_leak(self):
+        gg = []
+        def worker():
+            # main and additional *finished* greenlets
+            ll = greenlet.getcurrent().ll = []
+            def additional():
+                ll.append(greenlet.getcurrent())
+            for _ in range(2):
+                greenlet.greenlet(additional).switch()
+            gg.append(weakref.ref(greenlet.getcurrent()))
+        for _ in range(2):
+            t = threading.Thread(target=worker)
+            t.start()
+            t.join()
+            del t
+        greenlet.getcurrent() # update ts_current
+        self.recycle_threads()
+        greenlet.getcurrent() # update ts_current
+        gc.collect()
+        greenlet.getcurrent() # update ts_current
+        for g in gg:
+            self.assertIsNone(g())
+
+    def test_issue251_killing_cross_thread_leaks_list(self, manually_collect_background=True):
+        # See https://github.com/python-greenlet/greenlet/issues/251
+        # Killing a greenlet (probably not the main one)
+        # in one thread from another thread would
+        # result in leaking a list (the ts_delkey list).
+
+        # For the test to be valid, even empty lists have to be tracked by the
+        # GC
+        assert gc.is_tracked([])
+
+        def count_objects(kind=list):
+            # pylint:disable=unidiomatic-typecheck
+            # Collect the garbage.
+            for _ in range(3):
+                gc.collect()
+            gc.collect()
+            return sum(
+                1
+                for x in gc.get_objects()
+                if type(x) is kind
+            )
+
+        # XXX: The main greenlet of a dead thread is only released
+        # when one of the proper greenlet APIs is used from a different
+        # running thread. See #252 (https://github.com/python-greenlet/greenlet/issues/252)
+        greenlet.getcurrent()
+        greenlets_before = count_objects(greenlet.greenlet)
+
+        background_glet_running = threading.Event()
+        background_glet_killed = threading.Event()
+        background_greenlets = []
+        def background_greenlet():
+            # Throw control back to the main greenlet.
+            greenlet.getcurrent().parent.switch()
+
+        def background_thread():
+            glet = greenlet.greenlet(background_greenlet)
+            background_greenlets.append(glet)
+            glet.switch() # Be sure it's active.
+            # Control is ours again.
+            del glet # Delete one reference from the thread it runs in.
+            background_glet_running.set()
+            background_glet_killed.wait()
+            # To trigger the background collection of the dead
+            # greenlet, thus clearing out the contents of the list, we
+            # need to run some APIs. See issue 252.
+            if manually_collect_background:
+                greenlet.getcurrent()
+
+
+        t = threading.Thread(target=background_thread)
+        t.start()
+        background_glet_running.wait()
+
+        lists_before = count_objects()
+
+        assert len(background_greenlets) == 1
+        self.assertFalse(background_greenlets[0].dead)
+        # Delete the last reference to the background greenlet
+        # from a different thread. This puts it in the background thread's
+        # ts_delkey list.
+        del background_greenlets[:]
+        background_glet_killed.set()
+
+        # Now wait for the background thread to die.
+        t.join(10)
+        del t
+
+        # Free the background main greenlet by forcing greenlet to notice a difference.
+        greenlet.getcurrent()
+        greenlets_after = count_objects(greenlet.greenlet)
+
+        lists_after = count_objects()
+        # On 2.7, we observe that lists_after is smaller than
+        # lists_before. No idea what lists got cleaned up. All the
+        # Python 3 versions match exactly.
+        self.assertLessEqual(lists_after, lists_before)
+
+        self.assertEqual(greenlets_before, greenlets_after)
+
+    @unittest.expectedFailure
+    def test_issue251_issue252_need_to_collect_in_background(self):
+        # This still fails because the leak of the list
+        # still exists when we don't call a greenlet API before exiting the
+        # thread. The proximate cause is that neither of the two greenlets
+        # from the background thread are actually being destroyed, even though
+        # the GC is in fact visiting both objects.
+        # It's not clear where that leak is? For some reason the thread-local dict
+        # holding it isn't being cleaned up.
+        self.test_issue251_killing_cross_thread_leaks_list(manually_collect_background=False)
diff --git a/lib/greenlet/tests/test_stack_saved.py b/lib/greenlet/tests/test_stack_saved.py
new file mode 100644
index 0000000..6c7353b
--- /dev/null
+++ b/lib/greenlet/tests/test_stack_saved.py
@@ -0,0 +1,19 @@
+import greenlet
+import unittest
+
+
+class Test(unittest.TestCase):
+
+    def test_stack_saved(self):
+        main = greenlet.getcurrent()
+        self.assertEqual(main._stack_saved, 0)
+
+        def func():
+            main.switch(main._stack_saved)
+
+        g = greenlet.greenlet(func)
+        x = g.switch()
+        assert x > 0, x
+        assert g._stack_saved > 0, g._stack_saved
+        g.switch()
+        assert g._stack_saved == 0, g._stack_saved
diff --git a/lib/greenlet/tests/test_throw.py b/lib/greenlet/tests/test_throw.py
new file mode 100644
index 0000000..a2014a9
--- /dev/null
+++ b/lib/greenlet/tests/test_throw.py
@@ -0,0 +1,100 @@
+import sys
+import unittest
+
+from greenlet import greenlet
+
+
+def switch(*args):
+    return greenlet.getcurrent().parent.switch(*args)
+
+
+class ThrowTests(unittest.TestCase):
+    def test_class(self):
+        def f():
+            try:
+                switch("ok")
+            except RuntimeError:
+                switch("ok")
+                return
+            switch("fail")
+        g = greenlet(f)
+        res = g.switch()
+        self.assertEqual(res, "ok")
+        res = g.throw(RuntimeError)
+        self.assertEqual(res, "ok")
+
+    def test_val(self):
+        def f():
+            try:
+                switch("ok")
+            except RuntimeError:
+                val = sys.exc_info()[1]
+                if str(val) == "ciao":
+                    switch("ok")
+                    return
+            switch("fail")
+
+        g = greenlet(f)
+        res = g.switch()
+        self.assertEqual(res, "ok")
+        res = g.throw(RuntimeError("ciao"))
+        self.assertEqual(res, "ok")
+
+        g = greenlet(f)
+        res = g.switch()
+        self.assertEqual(res, "ok")
+        res = g.throw(RuntimeError, "ciao")
+        self.assertEqual(res, "ok")
+
+    def test_kill(self):
+        def f():
+            switch("ok")
+            switch("fail")
+        g = greenlet(f)
+        res = g.switch()
+        self.assertEqual(res, "ok")
+        res = g.throw()
+        self.assertTrue(isinstance(res, greenlet.GreenletExit))
+        self.assertTrue(g.dead)
+        res = g.throw()    # immediately eaten by the already-dead greenlet
+        self.assertTrue(isinstance(res, greenlet.GreenletExit))
+
+    def test_throw_goes_to_original_parent(self):
+        main = greenlet.getcurrent()
+
+        def f1():
+            try:
+                main.switch("f1 ready to catch")
+            except IndexError:
+                return "caught"
+            else:
+                return "normal exit"
+
+        def f2():
+            main.switch("from f2")
+
+        g1 = greenlet(f1)
+        g2 = greenlet(f2, parent=g1)
+        self.assertRaises(IndexError, g2.throw, IndexError)
+        self.assertTrue(g2.dead)
+        self.assertTrue(g1.dead)
+
+        g1 = greenlet(f1)
+        g2 = greenlet(f2, parent=g1)
+        res = g1.switch()
+        self.assertEqual(res, "f1 ready to catch")
+        res = g2.throw(IndexError)
+        self.assertEqual(res, "caught")
+        self.assertTrue(g2.dead)
+        self.assertTrue(g1.dead)
+
+        g1 = greenlet(f1)
+        g2 = greenlet(f2, parent=g1)
+        res = g1.switch()
+        self.assertEqual(res, "f1 ready to catch")
+        res = g2.switch()
+        self.assertEqual(res, "from f2")
+        res = g2.throw(IndexError)
+        self.assertEqual(res, "caught")
+        self.assertTrue(g2.dead)
+        self.assertTrue(g1.dead)
diff --git a/lib/greenlet/tests/test_tracing.py b/lib/greenlet/tests/test_tracing.py
new file mode 100644
index 0000000..2ab4d71
--- /dev/null
+++ b/lib/greenlet/tests/test_tracing.py
@@ -0,0 +1,267 @@
+import sys
+import unittest
+import greenlet
+
+class SomeError(Exception):
+    pass
+
+class GreenletTracer(object):
+    oldtrace = None
+
+    def __init__(self, error_on_trace=False):
+        self.actions = []
+        self.error_on_trace = error_on_trace
+
+    def __call__(self, *args):
+        self.actions.append(args)
+        if self.error_on_trace:
+            raise SomeError
+
+    def __enter__(self):
+        self.oldtrace = greenlet.settrace(self)
+        return self.actions
+
+    def __exit__(self, *args):
+        greenlet.settrace(self.oldtrace)
+
+
+class TestGreenletTracing(unittest.TestCase):
+    """
+    Tests of ``greenlet.settrace()``
+    """
+
+    def test_greenlet_tracing(self):
+        main = greenlet.getcurrent()
+        def dummy():
+            pass
+        def dummyexc():
+            raise SomeError()
+
+        with GreenletTracer() as actions:
+            g1 = greenlet.greenlet(dummy)
+            g1.switch()
+            g2 = greenlet.greenlet(dummyexc)
+            self.assertRaises(SomeError, g2.switch)
+
+        self.assertEqual(actions, [
+            ('switch', (main, g1)),
+            ('switch', (g1, main)),
+            ('switch', (main, g2)),
+            ('throw', (g2, main)),
+        ])
+
+    def test_exception_disables_tracing(self):
+        main = greenlet.getcurrent()
+        def dummy():
+            main.switch()
+        g = greenlet.greenlet(dummy)
+        g.switch()
+        with GreenletTracer(error_on_trace=True) as actions:
+            self.assertRaises(SomeError, g.switch)
+            self.assertEqual(greenlet.gettrace(), None)
+
+        self.assertEqual(actions, [
+            ('switch', (main, g)),
+        ])
+
+
+class PythonTracer(object):
+    oldtrace = None
+
+    def __init__(self):
+        self.actions = []
+
+    def __call__(self, frame, event, arg):
+        # Record the co_name so we have an idea what function we're in.
+        self.actions.append((event, frame.f_code.co_name))
+
+    def __enter__(self):
+        self.oldtrace = sys.setprofile(self)
+        return self.actions
+
+    def __exit__(self, *args):
+        sys.setprofile(self.oldtrace)
+
+def tpt_callback():
+    return 42
+
+class TestPythonTracing(unittest.TestCase):
+    """
+    Tests of the interaction of ``sys.settrace()``
+    with greenlet facilities.
+
+    NOTE: Most of this is probably CPython specific.
+    """
+
+    maxDiff = None
+
+    def test_trace_events_trivial(self):
+        with PythonTracer() as actions:
+            tpt_callback()
+        # If we use the sys.settrace instead of setprofile, we get
+        # this:
+
+        # self.assertEqual(actions, [
+        #     ('call', 'tpt_callback'),
+        #     ('call', '__exit__'),
+        # ])
+
+        self.assertEqual(actions, [
+            ('return', '__enter__'),
+            ('call', 'tpt_callback'),
+            ('return', 'tpt_callback'),
+            ('call', '__exit__'),
+            ('c_call', '__exit__'),
+        ])
+
+    def _trace_switch(self, glet):
+        with PythonTracer() as actions:
+            glet.switch()
+        return actions
+
+    def _check_trace_events_func_already_set(self, glet):
+        actions = self._trace_switch(glet)
+        self.assertEqual(actions, [
+            ('return', '__enter__'),
+            ('c_call', '_trace_switch'),
+            ('call', 'run'),
+            ('call', 'tpt_callback'),
+            ('return', 'tpt_callback'),
+            ('return', 'run'),
+            ('c_return', '_trace_switch'),
+            ('call', '__exit__'),
+            ('c_call', '__exit__'),
+        ])
+
+    def test_trace_events_into_greenlet_func_already_set(self):
+        def run():
+            return tpt_callback()
+
+        self._check_trace_events_func_already_set(greenlet.greenlet(run))
+
+    def test_trace_events_into_greenlet_subclass_already_set(self):
+        class X(greenlet.greenlet):
+            def run(self):
+                return tpt_callback()
+        self._check_trace_events_func_already_set(X())
+
+    def _check_trace_events_from_greenlet_sets_profiler(self, g, tracer):
+        g.switch()
+        tpt_callback()
+        tracer.__exit__()
+        self.assertEqual(tracer.actions, [
+            ('return', '__enter__'),
+            ('call', 'tpt_callback'),
+            ('return', 'tpt_callback'),
+            ('return', 'run'),
+            ('call', 'tpt_callback'),
+            ('return', 'tpt_callback'),
+            ('call', '__exit__'),
+            ('c_call', '__exit__'),
+        ])
+
+
+    def test_trace_events_from_greenlet_func_sets_profiler(self):
+        tracer = PythonTracer()
+        def run():
+            tracer.__enter__()
+            return tpt_callback()
+
+        self._check_trace_events_from_greenlet_sets_profiler(greenlet.greenlet(run),
+                                                             tracer)
+
+    def test_trace_events_from_greenlet_subclass_sets_profiler(self):
+        tracer = PythonTracer()
+        class X(greenlet.greenlet):
+            def run(self):
+                tracer.__enter__()
+                return tpt_callback()
+
+        self._check_trace_events_from_greenlet_sets_profiler(X(), tracer)
+
+
+    def test_trace_events_multiple_greenlets_switching(self):
+        tracer = PythonTracer()
+
+        g1 = None
+        g2 = None
+
+        def g1_run():
+            tracer.__enter__()
+            tpt_callback()
+            g2.switch()
+            tpt_callback()
+            return 42
+
+        def g2_run():
+            tpt_callback()
+            tracer.__exit__()
+            tpt_callback()
+            g1.switch()
+
+        g1 = greenlet.greenlet(g1_run)
+        g2 = greenlet.greenlet(g2_run)
+
+        x = g1.switch()
+        self.assertEqual(x, 42)
+        tpt_callback() # ensure not in the trace
+        self.assertEqual(tracer.actions, [
+            ('return', '__enter__'),
+            ('call', 'tpt_callback'),
+            ('return', 'tpt_callback'),
+            ('c_call', 'g1_run'),
+            ('call', 'g2_run'),
+            ('call', 'tpt_callback'),
+            ('return', 'tpt_callback'),
+            ('call', '__exit__'),
+            ('c_call', '__exit__'),
+        ])
+
+    def test_trace_events_multiple_greenlets_switching_siblings(self):
+        # Like the first version, but get both greenlets running first
+        # as "siblings" and then establish the tracing.
+        tracer = PythonTracer()
+
+        g1 = None
+        g2 = None
+
+        def g1_run():
+            greenlet.getcurrent().parent.switch()
+            tracer.__enter__()
+            tpt_callback()
+            g2.switch()
+            tpt_callback()
+            return 42
+
+        def g2_run():
+            greenlet.getcurrent().parent.switch()
+
+            tpt_callback()
+            tracer.__exit__()
+            tpt_callback()
+            g1.switch()
+
+        g1 = greenlet.greenlet(g1_run)
+        g2 = greenlet.greenlet(g2_run)
+
+        # Start g1
+        g1.switch()
+        # And it immediately returns control to us.
+        # Start g2
+        g2.switch()
+        # Which also returns. Now kick of the real part of the
+        # test.
+        x = g1.switch()
+        self.assertEqual(x, 42)
+
+        tpt_callback() # ensure not in the trace
+        self.assertEqual(tracer.actions, [
+            ('return', '__enter__'),
+            ('call', 'tpt_callback'),
+            ('return', 'tpt_callback'),
+            ('c_call', 'g1_run'),
+            ('call', 'tpt_callback'),
+            ('return', 'tpt_callback'),
+            ('call', '__exit__'),
+            ('c_call', '__exit__'),
+        ])
diff --git a/lib/greenlet/tests/test_version.py b/lib/greenlet/tests/test_version.py
new file mode 100644
index 0000000..0c9a497
--- /dev/null
+++ b/lib/greenlet/tests/test_version.py
@@ -0,0 +1,39 @@
+#! /usr/bin/env python
+from __future__ import absolute_import
+from __future__ import print_function
+
+import sys
+import os
+import unittest
+
+import greenlet
+
+class VersionTests(unittest.TestCase):
+    def test_version(self):
+        def find_dominating_file(name):
+            if os.path.exists(name):
+                return name
+
+            tried = []
+            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)
+                tried.append(fname)
+                if os.path.exists(fname):
+                    return fname
+            raise AssertionError("Could not find file " + name + "; checked " + str(tried))
+
+        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))
+
+
+        invoke_setup = "%s %s --version" % (sys.executable, setup_py)
+        with os.popen(invoke_setup) as f:
+            sversion = f.read().strip()
+
+        self.assertEqual(sversion, greenlet.__version__)
diff --git a/lib/greenlet/tests/test_weakref.py b/lib/greenlet/tests/test_weakref.py
new file mode 100644
index 0000000..6a2ff06
--- /dev/null
+++ b/lib/greenlet/tests/test_weakref.py
@@ -0,0 +1,34 @@
+import gc
+import greenlet
+import weakref
+import unittest
+
+
+class WeakRefTests(unittest.TestCase):
+    def test_dead_weakref(self):
+        def _dead_greenlet():
+            g = greenlet.greenlet(lambda: None)
+            g.switch()
+            return g
+        o = weakref.ref(_dead_greenlet())
+        gc.collect()
+        self.assertEqual(o(), None)
+
+    def test_inactive_weakref(self):
+        o = weakref.ref(greenlet.greenlet())
+        gc.collect()
+        self.assertEqual(o(), None)
+
+    def test_dealloc_weakref(self):
+        seen = []
+        def worker():
+            try:
+                greenlet.getcurrent().parent.switch()
+            finally:
+                seen.append(g())
+        g = greenlet.greenlet(worker)
+        g.switch()
+        g2 = greenlet.greenlet(lambda: None, g)
+        g = weakref.ref(g2)
+        g2 = None
+        self.assertEqual(seen, [None])