Tests for task-local-storage

tests/test_tls.py

@@ -0,0 +1,86 @@
+# test_tls.py
+
+import pytest
+from curio import *
+
+# Like run, but unwraps exceptions so pytest can see them properly.
+# Lets us use assert from inside async functions.
+def run_with_real_exceptions(*args, **kwargs):
+    try:
+        return run(*args, **kwargs)
+    except TaskError as e:
+        real = e.__cause__
+        # we can't avoid ending up with real.__context__ == e
+        # and if e.__cause__ = real then we end up with a reference loop that
+        # makes py.test blow up. So we have to None-out e.__cause__. (del is
+        # illegal.)
+        e.__cause__ = None
+        raise real from None
+
+def test_smoketest():
+    local = Local()
+
+    async def smoketest():
+        local.a = 1
+        assert local.a == 1
+        del local.a
+        with pytest.raises(AttributeError):
+            local.a
+        with pytest.raises(AttributeError):
+            del local.a
+
+    run_with_real_exceptions(smoketest())
+
+def test_isolation():
+    local = Local()
+
+    event1 = Event()
+    event2 = Event()
+    async def check_isolated_1():
+        local.a = 1
+        await event1.set()
+        await event2.wait()
+        assert local.a == 1
+
+    async def check_isolated_2():
+        await event1.wait()
+        # another task has done local.a = 1, but we shouldn't be able to see
+        # it
+        assert not hasattr(local, "a")
+        # Just like our assignment shouldn't be visible to them
+        local.a = 2
+        await event2.set()
+
+    async def check_isolated():
+        for task in [await spawn(check_isolated_1()),
+                     await spawn(check_isolated_2())]:
+            await task.join()
+
+    run_with_real_exceptions(check_isolated())
+
+def test_inheritance():
+    local = Local()
+
+    event1 = Event()
+    event2 = Event()
+    async def parent():
+        local.a = "both"
+        assert local.a == "both"
+        child_task = await spawn(child())
+        # now let the child check that it got the value, and try to change it
+        await event1.wait()
+        # child modification shouldn't be visible here
+        assert local.a == "both"
+        # and now check that the child can't see our change
+        local.a = "parent"
+        await event2.set()
+
+    async def child():
+        assert local.a == "both"
+        local.a == "child"
+        assert local.a == "child"
+        await event1.set()
+        await event2.wait()
+        assert local.a == "child"
+
+    run_with_real_exceptions(parent())