wcfs: tests: Move test for verifying protection against faulty/slow clients to dedicated file

We are going to add more tests on this topic + supporting infrastructure.
It makes sense to move everything related to dedicated test file first
as a preparatory step because wcfs_test.py feels already overloaded.

Plain code movement.

/reviewed-by @levin.zimmermann
/reviewed-on !18

wcfs/wcfs_faultyprot_test.py

+# -*- coding: utf-8 -*-
+# Copyright (C) 2018-2024  Nexedi SA and Contributors.
+#                          Kirill Smelkov <kirr@nexedi.com>
+#
+# This program is free software: you can Use, Study, Modify and Redistribute
+# it under the terms of the GNU General Public License version 3, or (at your
+# option) any later version, as published by the Free Software Foundation.
+#
+# You can also Link and Combine this program with other software covered by
+# the terms of any of the Free Software licenses or any of the Open Source
+# Initiative approved licenses and Convey the resulting work. Corresponding
+# source of such a combination shall include the source code for all other
+# software used.
+#
+# This program is distributed WITHOUT ANY WARRANTY; without even the implied
+# warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+#
+# See COPYING file for full licensing terms.
+# See https://www.nexedi.com/licensing for rationale and options.
+"""wcfs_faultyprot_test.py complements wcfs_test.py with tests that exercise
+protection against slow/faulty clients in isolation protocol."""
+
+from __future__ import print_function, absolute_import
+
+from golang import select, func, defer
+from golang import context, sync, time
+
+import pytest; xfail = pytest.mark.xfail
+from pytest import fail
+from wendelin.wcfs.wcfs_test import tDB, h, \
+        setup_module, teardown_module, setup_function, teardown_function
+
+
+# verify that wcfs kills slow/faulty client who does not reply to pin in time.
+@xfail  # protection against faulty/slow clients
+@func
+def test_wcfs_pintimeout_kill():
+    # adjusted wcfs timeout to kill client who is stuck not providing pin reply
+    tkill = 3*time.second
+    t = tDB(); zf = t.zfile     # XXX wcfs args += tkill=<small>
+    defer(t.close)
+
+    at1 = t.commit(zf, {2:'c1'})
+    at2 = t.commit(zf, {2:'c2'})
+    f = t.open(zf)
+    f.assertData(['','','c2'])
+
+    # XXX move into subprocess not to kill whole testing
+    ctx, _ = context.with_timeout(context.background(), 2*tkill)
+
+    wl = t.openwatch()
+    wg = sync.WorkGroup(ctx)
+    def _(ctx):
+        # send watch. The pin handler won't be replying -> we should never get reply here.
+        wl.sendReq(ctx, b"watch %s @%s" % (h(zf._p_oid), h(at1)))
+        fail("watch request completed (should not as pin handler is stuck)")
+    wg.go(_)
+    def _(ctx):
+        req = wl.recvReq(ctx)
+        assert req is not None
+        assert req.msg == b"pin %s #%d @%s" % (h(zf._p_oid), 2, h(at1))
+
+        # sleep > wcfs pin timeout - wcfs must kill us
+        _, _rx = select(
+            ctx.done().recv,        # 0
+            time.after(tkill).recv, # 1
+        )
+        if _ == 0:
+            raise ctx.err()
+        fail("wcfs did not killed stuck client")
+    wg.go(_)
+    wg.wait()

wcfs/wcfs_test.py

@@ -22,6 +22,9 @@
 Virtmem layer provided by wcfs client package is unit-tested by
 wcfs/client/client_test.py .
 
+Protection from slow or faulty clients is unit-tested by
+wcfs/wcfs_faultyprot_test.py .
+
 At functional level, the whole wendelin.core test suite is used to verify
 wcfs.py/wcfs.go while running tox tests in wcfs mode.
 """
@@ -49,7 +52,6 @@ from resource import setrlimit, getrlimit, RLIMIT_MEMLOCK
 from golang import go, chan, select, func, defer, error, b
 from golang import context, errors, sync, time
 from zodbtools.util import ashex as h, fromhex
-import pytest; xfail = pytest.mark.xfail
 from pytest import raises, fail
 from wendelin.wcfs.internal import io, mm
 from wendelin.wcfs.internal.wcfs_test import _tWCFS, read_exfault_nogil, SegmentationFault, install_sigbus_trap, fadvise_dontneed
@@ -1533,45 +1535,7 @@ def test_wcfs_watch_going_back():
     wl.close()
 
 
-# verify that wcfs kills slow/faulty client who does not reply to pin in time.
-@xfail  # protection against faulty/slow clients
-@func
-def test_wcfs_pintimeout_kill():
-    # adjusted wcfs timeout to kill client who is stuck not providing pin reply
-    tkill = 3*time.second
-    t = tDB(); zf = t.zfile     # XXX wcfs args += tkill=<small>
-    defer(t.close)
-
-    at1 = t.commit(zf, {2:'c1'})
-    at2 = t.commit(zf, {2:'c2'})
-    f = t.open(zf)
-    f.assertData(['','','c2'])
-
-    # XXX move into subprocess not to kill whole testing
-    ctx, _ = context.with_timeout(context.background(), 2*tkill)
-
-    wl = t.openwatch()
-    wg = sync.WorkGroup(ctx)
-    def _(ctx):
-        # send watch. The pin handler won't be replying -> we should never get reply here.
-        wl.sendReq(ctx, b"watch %s @%s" % (h(zf._p_oid), h(at1)))
-        fail("watch request completed (should not as pin handler is stuck)")
-    wg.go(_)
-    def _(ctx):
-        req = wl.recvReq(ctx)
-        assert req is not None
-        assert req.msg == b"pin %s #%d @%s" % (h(zf._p_oid), 2, h(at1))
-
-        # sleep > wcfs pin timeout - wcfs must kill us
-        _, _rx = select(
-            ctx.done().recv,        # 0
-            time.after(tkill).recv, # 1
-        )
-        if _ == 0:
-            raise ctx.err()
-        fail("wcfs did not killed stuck client")
-    wg.go(_)
-    wg.wait()
+# tests for "Protection against slow or faulty clients" are in wcfs_faultyprot_test.py
 
 
 # watch with @at > head - must wait for head to become >= at.