[Libguestfs] [PATCH nbdkit v2 10/10] tests: Test the Python plugin thoroughly.
Nir Soffer
nsoffer at redhat.com
Sat Nov 23 01:31:39 UTC 2019
On Sat, Nov 23, 2019 at 1:42 AM Nir Soffer <nsoffer at redhat.com> wrote:
>
> On Fri, Nov 22, 2019 at 9:55 PM Richard W.M. Jones <rjones at redhat.com> wrote:
> >
> > This tests the Python plugin thoroughly by issuing client commands
> > through libnbd and checking we get the expected results.
> > ---
> > tests/Makefile.am | 13 +--
> > tests/test-python-plugin.py | 134 ++++++++++++++++++++++++++++
> > tests/test-python.py | 172 ++++++++++++++++++++++++++++++++++++
> > tests/test.py | 60 -------------
> > 4 files changed, 309 insertions(+), 70 deletions(-)
> >
> > diff --git a/tests/Makefile.am b/tests/Makefile.am
> > index 13cd8f3..88849f5 100644
> > --- a/tests/Makefile.am
> > +++ b/tests/Makefile.am
> > @@ -115,7 +115,8 @@ EXTRA_DIST = \
> > test-pattern-largest-for-qemu.sh \
> > test-python-exception.sh \
> > test.pl \
> > - test.py \
> > + test-python.py \
> > + test-python-plugin.py \
> > test-rate.sh \
> > test-rate-dynamic.sh \
> > test.rb \
> > @@ -787,18 +788,10 @@ endif HAVE_PERL
> > if HAVE_PYTHON
> >
> > TESTS += \
> > + test-python.py \
> > test-python-exception.sh \
> > test-shebang-python.sh \
> > $(NULL)
> > -LIBGUESTFS_TESTS += test-python
> > -
> > -test_python_SOURCES = test-lang-plugins.c test.h
> > -test_python_CFLAGS = \
> > - -DLANG='"python"' -DSCRIPT='"$(srcdir)/test.py"' \
> > - $(WARNINGS_CFLAGS) \
> > - $(LIBGUESTFS_CFLAGS) \
> > - $(NULL)
> > -test_python_LDADD = libtest.la $(LIBGUESTFS_LIBS)
> >
> > endif HAVE_PYTHON
> >
> > diff --git a/tests/test-python-plugin.py b/tests/test-python-plugin.py
> > new file mode 100644
> > index 0000000..053a380
> > --- /dev/null
> > +++ b/tests/test-python-plugin.py
> > @@ -0,0 +1,134 @@
> > +#!/usr/bin/env python3
> > +# nbdkit
> > +# Copyright (C) 2019 Red Hat Inc.
> > +#
> > +# Redistribution and use in source and binary forms, with or without
> > +# modification, are permitted provided that the following conditions are
> > +# met:
> > +#
> > +# * Redistributions of source code must retain the above copyright
> > +# notice, this list of conditions and the following disclaimer.
> > +#
> > +# * Redistributions in binary form must reproduce the above copyright
> > +# notice, this list of conditions and the following disclaimer in the
> > +# documentation and/or other materials provided with the distribution.
> > +#
> > +# * Neither the name of Red Hat nor the names of its contributors may be
> > +# used to endorse or promote products derived from this software without
> > +# specific prior written permission.
> > +#
> > +# THIS SOFTWARE IS PROVIDED BY RED HAT AND CONTRIBUTORS ''AS IS'' AND
> > +# ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
> > +# THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
> > +# PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL RED HAT OR
> > +# CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
> > +# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
> > +# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
> > +# USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
> > +# ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
> > +# OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
> > +# OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
> > +# SUCH DAMAGE.
> > +
> > +# See test-python.py.
> > +
> > +import nbdkit
> > +import sys
> > +import pickle
> > +import codecs
> > +
> > +def api_version ():
> > + return 2
> > +
> > +cfg = {}
> > +
> > +def config (k, v):
> > + global cfg
> > + if k == "cfg":
> > + cfg = pickle.loads (codecs.decode (v.encode(), "base64"))
> > +
> > +def config_complete ():
> > + print ("set_error = %r" % nbdkit.set_error)
> > +
> > +def open (readonly):
> > + return {
> > + 'disk': bytearray (cfg.get ('size', 0))
> > + }
> > +
> > +def get_size (h):
> > + return len (h['disk'])
> > +
> > +def is_rotational(h):
> > + return cfg.get ('is_rotational', False)
> > +
> > +def can_multi_conn (h):
> > + return cfg.get ('can_multi_conn', False)
> > +
> > +def can_write (h):
> > + return cfg.get ('can_write', True)
> > +
> > +def can_flush(h):
> > + return cfg.get ('can_flush', False)
> > +
> > +def can_trim(h):
> > + return cfg.get ('can_trim', False)
> > +
> > +def can_zero(h):
> > + return cfg.get ('can_zero', False)
> > +
> > +def can_fast_zero(h):
> > + return cfg.get ('can_fast_zero', False)
> > +
> > +def can_fua(h):
> > + fua = cfg.get ('can_fua', "none")
> > + if fua == "none":
> > + return nbdkit.FUA_NONE
> > + elif fua == "emulate":
> > + return nbdkit.FUA_EMULATE
> > + elif fua == "native":
> > + return nbdkit.FUA_NATIVE
> > +
> > +def can_cache(h):
> > + cache = cfg.get ('can_cache', "none")
> > + if cache == "none":
> > + return nbdkit.CACHE_NONE
> > + elif cache == "emulate":
> > + return nbdkit.CACHE_EMULATE
> > + elif cache == "native":
> > + return nbdkit.CACHE_NATIVE
> > +
> > +def pread(h, count, offset, flags):
> > + assert flags == 0
> > + return h['disk'][offset:offset+count]
>
> Very nice and simple test plugin!
>
> But this returns always a bytearray, which is also what nbdkit python plugin
> expects. But real code using HTTPConnection return bytes:
>
> >>> c = http.client.HTTPSConnection("www.python.org")
> >>> c.request("GET", "/")
> >>> r = c.getresponse()
> >>> r.read()[:10]
> b'<!doctype '
>
> I think the plugin should support both bytearray, memoryview, or
> bytes. Supporting objects
> implementing the buffer protocol would be best.
This patch adds support for buffer protocol:
https://www.redhat.com/archives/libguestfs/2019-November/msg00200.html
(I forgot to add nbdkit to the title)
>
> > +
> > +def pwrite(h, buf, offset, flags):
> > + expect_fua = cfg.get ('pwrite_expect_fua', False)
> > + actual_fua = bool (flags & nbdkit.FLAG_FUA)
> > + assert expect_fua == actual_fua
> > + end = offset + len(buf)
> > + h['disk'][offset:end] = buf
> > +
> > +def flush(h, flags):
> > + assert flags == 0
> > +
> > +def trim(h, count, offset, flags):
> > + expect_fua = cfg.get ('trim_expect_fua', False)
> > + actual_fua = bool (flags & nbdkit.FLAG_FUA)
> > + assert expect_fua == actual_fua
> > + h['disk'][offset:offset+count] = bytearray(count)
> > +
> > +def zero(h, count, offset, flags):
> > + expect_fua = cfg.get ('zero_expect_fua', False)
> > + actual_fua = bool (flags & nbdkit.FLAG_FUA)
> > + assert expect_fua == actual_fua
> > + expect_may_trim = cfg.get ('zero_expect_may_trim', False)
> > + actual_may_trim = bool (flags & nbdkit.FLAG_MAY_TRIM)
> > + assert expect_may_trim == actual_may_trim
> > + expect_fast_zero = cfg.get ('zero_expect_fast_zero', False)
> > + actual_fast_zero = bool (flags & nbdkit.FLAG_FAST_ZERO)
> > + assert expect_fast_zero == actual_fast_zero
> > + h['disk'][offset:offset+count] = bytearray(count)
> > +
> > +def cache(h, count, offset, flags):
> > + assert flags == 0
> > + # do nothing
> > diff --git a/tests/test-python.py b/tests/test-python.py
> > new file mode 100755
> > index 0000000..2f565ba
> > --- /dev/null
> > +++ b/tests/test-python.py
> > @@ -0,0 +1,172 @@
> > +#!/usr/bin/env python3
> > +# nbdkit
> > +# Copyright (C) 2019 Red Hat Inc.
> > +#
> > +# Redistribution and use in source and binary forms, with or without
> > +# modification, are permitted provided that the following conditions are
> > +# met:
> > +#
> > +# * Redistributions of source code must retain the above copyright
> > +# notice, this list of conditions and the following disclaimer.
> > +#
> > +# * Redistributions in binary form must reproduce the above copyright
> > +# notice, this list of conditions and the following disclaimer in the
> > +# documentation and/or other materials provided with the distribution.
> > +#
> > +# * Neither the name of Red Hat nor the names of its contributors may be
> > +# used to endorse or promote products derived from this software without
> > +# specific prior written permission.
> > +#
> > +# THIS SOFTWARE IS PROVIDED BY RED HAT AND CONTRIBUTORS ''AS IS'' AND
> > +# ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
> > +# THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
> > +# PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL RED HAT OR
> > +# CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
> > +# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
> > +# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
> > +# USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
> > +# ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
> > +# OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
> > +# OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
> > +# SUCH DAMAGE.
> > +
> > +# This tests the Python plugin thoroughly by issuing client commands
> > +# through libnbd and checking we get the expected results. It uses an
> > +# associated plugin (test-python-plugin.sh).
>
> test-python-plugin.py
>
> This text can use python docstring:
>
> """
> This tests ...
> """
>
> > +
> > +import os
> > +import sys
> > +import pickle
> > +import codecs
> > +
> > +# Python has proven very difficult to valgrind, therefore it is disabled.
> > +if "NBDKIT_VALGRIND" in os.environ:
> > + print ("$s: skipping Python test under valgrind" % __file__)
> > + sys.exit (77)
> > +
> > +try:
> > + import nbd
> > +except:
>
> except ImportError:
>
> > + print ("%s: skipped because cannot import python libnbd" % __file__)
> > + sys.exit (77)
> > +
> > +try:
> > + srcdir = os.environ['SRCDIR']
> > +except:
>
> except KeyError:
>
> > + print ("%s: FAIL: test failed because $SRCDIR is not set" % __file__)
> > + sys.exit (1)
> > +
> > +def test (cfg):
>
> test will fool testing frameworks, expecting that this is a test function.
> Maybe call this handle()? or case()?
>
> > + h = nbd.NBD ()
> > + cfg = codecs.encode (pickle.dumps (cfg), "base64").decode()
>
> base64.b64encode() is better, avoiding unwanted newlines.
>
> > + cmd = ["nbdkit", "-v", "-s", "--exit-with-parent",
> > + "python", srcdir + "/test-python-plugin.py",
> > + "cfg=" + cfg]
> > + h.connect_command (cmd)
> > + return h
> > +
> > +# Test we can send an empty pickled test configuration and do nothing
> > +# else. This is just to ensure the machinery of the test works.
> > +h = test ({})
>
> So we have now running nbdkit that will exit the python collects when h
> is implicitly closed when creating a new handle?
>
> This is fragile, but can be solved with the help of a testing framework.
>
> > +
> > +# Test the size.
> > +h = test ({"size": 512})
> > +assert h.get_size() == 512
> > +h = test ({"size": 1024*1024})
> > +assert h.get_size() == 1024*1024
>
> These tests will fail when on the first error, which is less useful.
>
> With very little work we can convert this to pytest:
>
> def test_size():
> h = test()
> assert h.get_size() == 512
>
> To run the test you use:
>
> pytest test-python.py
>
> > +
> > +# Test each flag call.
> > +h = test ({"size": 512, "is_rotational": True})
> > +assert h.is_rotational()
> > +h = test ({"size": 512, "is_rotational": False})
> > +assert not h.is_rotational()
>
> When this fails, you will get unhelpful output:
>
> assert not True
>
> But with pytest you get much more useful error, something like:
>
> def test_is_rotational():
> h = handle ({"size": 512, "is_rotational": True})
> > assert not h.is_rotational
> E assert not True
> E + where True = <test.handle.<locals>.H object at
> 0x7faa3358e450>.is_rotational
>
> (I faked the handle object for this example)
>
> > +
> > +h = test ({"size": 512, "can_multi_conn": True})
> > +assert h.can_multi_conn()
> > +h = test ({"size": 512, "can_multi_conn": False})
> > +assert not h.can_multi_conn()
> > +
> > +h = test ({"size": 512, "can_write": True})
> > +assert not h.is_read_only()
> > +h = test ({"size": 512, "can_write": False})
> > +assert h.is_read_only()
> > +
> > +h = test ({"size": 512, "can_flush": True})
> > +assert h.can_flush()
> > +h = test ({"size": 512, "can_flush": False})
> > +assert not h.can_flush()
> > +
> > +h = test ({"size": 512, "can_trim": True})
> > +assert h.can_trim()
> > +h = test ({"size": 512, "can_trim": False})
> > +assert not h.can_trim()
> > +
> > +# nbdkit can always zero because it emulates it.
> > +#h = test ({"size": 512, "can_zero": True})
> > +#assert h.can_zero()
> > +#h = test ({"size": 512, "can_zero": False})
> > +#assert not h.can_zero()
> > +
> > +h = test ({"size": 512, "can_fast_zero": True})
> > +assert h.can_fast_zero()
> > +h = test ({"size": 512, "can_fast_zero": False})
> > +assert not h.can_fast_zero()
> > +
> > +h = test ({"size": 512, "can_fua": "none"})
> > +assert not h.can_fua()
> > +h = test ({"size": 512, "can_fua": "emulate"})
> > +assert h.can_fua()
> > +h = test ({"size": 512, "can_fua": "native"})
> > +assert h.can_fua()
> > +
> > +h = test ({"size": 512, "can_cache": "none"})
> > +assert not h.can_cache()
> > +h = test ({"size": 512, "can_cache": "emulate"})
> > +assert h.can_cache()
> > +h = test ({"size": 512, "can_cache": "native"})
> > +assert h.can_cache()
> > +
> > +# Not yet implemented: can_extents.
> > +
> > +# Test pread.
> > +h = test ({"size": 512})
> > +buf = h.pread (512, 0)
> > +
> > +# Test pwrite + flags.
> > +h = test ({"size": 512})
> > +h.pwrite (buf, 0)
> > +
> > +h = test ({"size": 512, "can_fua": "native", "pwrite_expect_fua": True})
> > +h.pwrite (buf, 0, nbd.CMD_FLAG_FUA)
> > +
> > +# Test flush.
> > +h = test ({"size": 512, "can_flush": True})
> > +h.flush ()
> > +
> > +# Test trim + flags.
> > +h = test ({"size": 512, "can_trim": True})
> > +h.trim (512, 0)
> > +
> > +h = test ({"size": 512,
> > + "can_trim": True, "can_fua": "native", "trim_expect_fua": True})
>
> This becomes messy. With the dict does not fit in one line, or
> contains more than
> few keys it is more readable to use one key: value pair per line.
>
> > +h.trim (512, 0, nbd.CMD_FLAG_FUA)
> > +
> > +# Test zero + flags.
> > +h = test ({"size": 512, "can_zero": True})
> > +h.zero (512, 0, nbd.CMD_FLAG_NO_HOLE)
> > +
> > +h = test ({"size": 512,
> > + "can_zero": True, "can_fua": "native", "zero_expect_fua": True})
> > +h.zero (512, 0, nbd.CMD_FLAG_NO_HOLE | nbd.CMD_FLAG_FUA)
> > +
> > +h = test ({"size": 512, "can_zero": True, "zero_expect_may_trim": True})
> > +h.zero (512, 0, 0) # absence of nbd.CMD_FLAG_NO_HOLE
> > +
> > +h = test ({"size": 512,
> > + "can_zero": True, "can_fast_zero": True,
> > + "zero_expect_fast_zero": True})
> > +h.zero (512, 0, nbd.CMD_FLAG_NO_HOLE | nbd.CMD_FLAG_FAST_ZERO)
> > +
> > +# Test cache.
> > +h = test ({"size": 512, "can_cache": "native"})
> > +h.cache (512, 0)
> > diff --git a/tests/test.py b/tests/test.py
> > deleted file mode 100644
> > index ac80d96..0000000
> > --- a/tests/test.py
> > +++ /dev/null
> > @@ -1,60 +0,0 @@
> > -import nbdkit
> > -
> > -disk = bytearray(1024*1024)
> > -
> > -
> > -def api_version():
> > - return 2
> > -
> > -
> > -def config_complete():
> > - print ("set_error = %r" % nbdkit.set_error)
> > -
> > -
> > -def open(readonly):
> > - return 1
> > -
> > -
> > -def get_size(h):
> > - global disk
> > - return len(disk)
> > -
> > -
> > -def can_write(h):
> > - return True
> > -
> > -
> > -def can_flush(h):
> > - return True
> > -
> > -
> > -def is_rotational(h):
> > - return False
> > -
> > -
> > -def can_trim(h):
> > - return True
> > -
> > -
> > -def pread(h, count, offset, flags):
> > - global disk
> > - return disk[offset:offset+count]
> > -
> > -
> > -def pwrite(h, buf, offset, flags):
> > - global disk
> > - end = offset + len(buf)
> > - disk[offset:end] = buf
> > -
> > -
> > -def flush(h, flags):
> > - pass
> > -
> > -
> > -def trim(h, count, offset, flags):
> > - pass
> > -
> > -
> > -def zero(h, count, offset, flags):
> > - global disk
> > - disk[offset:offset+count] = bytearray(count)
> > --
> > 2.23.0
> >
>
> Otherwise very nice tests!
>
> Nir
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