mirror of
https://github.com/retspen/webvirtcloud
synced 2026-11-08 19:26:48 +00:00
439f24041e
Measured on a VM with two disks, a CD-ROM and a NIC: 70 libvirt calls per page, now 43. Within the page's cached_reads block the VM's state, the host's info and domain capabilities, and each disk path's volume are read once; the running and the persistent disk lists share a path's volume. The ISO list takes the active pools in one call instead of looking each up by name; it still refreshes them, so an image copied in by hand shows up. The opt-in DRBD status waits at most 10 s for the compute's ssh, then leaves the status unknown instead of holding the page.
222 lines
7.8 KiB
Python
222 lines
7.8 KiB
Python
"""wvmInstance.cached_reads(): inside the block the domain XML (per flags),
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the VM's state, the host capabilities and info, and each disk's volume are
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read from libvirt once; outside it every read goes to libvirt, as code that
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changes the VM needs."""
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import unittest
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from unittest.mock import MagicMock, patch
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from django.conf import settings
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if not settings.configured:
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settings.configure(MAC_OUI="52:54:10")
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from libvirt import libvirtError
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from vrtManager.connection import wvmConnect
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from vrtManager.instance import wvmInstance
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class FakeDomain:
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def __init__(self):
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self.reads = []
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self.fail = False
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def info(self):
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self.reads.append("info")
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return [1, 0, 0, 0, 0]
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def XMLDesc(self, flags):
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if self.fail:
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raise RuntimeError("libvirt error")
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self.reads.append(flags)
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return f"<domain flags='{flags}' read='{len(self.reads)}'/>"
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class FakeConn:
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def __init__(self):
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self.caps = 0
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self.defined = []
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def getInfo(self):
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self.caps += 1
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return ["x86_64", 2048, 4, 0, 1, 2, 2, 1]
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def getCapabilities(self):
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self.caps += 1
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return "<capabilities/>"
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def defineXML(self, xml):
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self.defined.append(xml)
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def proxy():
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p = wvmInstance.__new__(wvmInstance) # no connection: only these calls
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p.instance = FakeDomain()
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p.wvm = FakeConn()
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return p
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class CachedReadsTestCase(unittest.TestCase):
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def test_outside_the_block_every_read_goes_to_libvirt(self):
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p = proxy()
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p._XMLDesc(0)
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p._XMLDesc(0)
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p.get_cap_xml()
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p.get_cap_xml()
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self.assertEqual((p.instance.reads, p.wvm.caps), ([0, 0], 2))
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def test_inside_the_block_each_flags_value_is_read_once(self):
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p = proxy()
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with p.cached_reads():
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first = [p._XMLDesc(0), p._XMLDesc(1), p._XMLDesc(3)]
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again = [p._XMLDesc(0), p._XMLDesc(1), p._XMLDesc(3)]
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p.get_cap_xml()
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p.get_cap_xml()
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self.assertEqual(first, again)
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self.assertEqual(p.instance.reads, [0, 1, 3])
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self.assertEqual(p.wvm.caps, 1)
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def test_the_block_ends_with_its_cache(self):
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p = proxy()
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with p.cached_reads():
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p._XMLDesc(0)
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with p.cached_reads():
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p._XMLDesc(0)
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p._XMLDesc(0)
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self.assertEqual(p.instance.reads, [0, 0, 0])
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def test_an_error_inside_the_block_still_ends_it(self):
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p = proxy()
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with self.assertRaises(ValueError), p.cached_reads():
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p._XMLDesc(0)
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raise ValueError
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p._XMLDesc(0)
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self.assertEqual(p.instance.reads, [0, 0])
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def test_a_failed_read_is_not_cached(self):
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p = proxy()
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with p.cached_reads():
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p.instance.fail = True
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with self.assertRaises(RuntimeError):
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p._XMLDesc(0)
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p.instance.fail = False
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p._XMLDesc(0)
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self.assertEqual(p.instance.reads, [0])
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def test_a_definition_change_drops_the_cache(self):
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p = proxy()
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with p.cached_reads():
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p._XMLDesc(3)
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p._defineXML("<domain/>")
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p._XMLDesc(3)
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self.assertEqual(p.instance.reads, [3, 3])
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def test_blocks_do_not_nest(self):
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p = proxy()
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with p.cached_reads(), self.assertRaises(RuntimeError), p.cached_reads():
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pass
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def test_two_proxies_do_not_share_a_cache(self):
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a, b = proxy(), proxy()
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with a.cached_reads():
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a._XMLDesc(0)
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b._XMLDesc(0)
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b._XMLDesc(0)
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self.assertEqual((a.instance.reads, b.instance.reads), ([0], [0, 0]))
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def test_the_state_and_host_info_are_read_once(self):
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p = proxy()
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with p.cached_reads():
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for _ in range(2):
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p.get_status()
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p.get_max_memory()
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p.get_max_cpus()
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self.assertEqual((p.instance.reads, p.wvm.caps), (["info"], 1))
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p.get_status()
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self.assertEqual(p.instance.reads, ["info", "info"])
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def test_domain_capabilities_are_read_once_per_arch_and_machine(self):
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p = proxy()
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with patch.object(wvmConnect, "get_dom_cap_xml", return_value="<domainCapabilities/>") as read:
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with p.cached_reads():
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for _ in range(2):
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p.get_dom_cap_xml("x86_64", "q35")
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p.get_dom_cap_xml("x86_64", "pc")
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p.get_dom_cap_xml("x86_64", "q35")
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self.assertEqual([c.args for c in read.call_args_list], [("x86_64", "q35"), ("x86_64", "pc"), ("x86_64", "q35")])
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def volume_proxy(paths):
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"""A proxy whose host has volumes at paths (pool "pool", size 10, used 4)."""
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p = proxy()
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p.lookups = []
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def lookup(path):
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p.lookups.append(path)
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if path not in paths:
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raise libvirtError("no storage vol with matching path")
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vol = MagicMock()
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vol.name.return_value = path.rsplit("/", 1)[-1]
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vol.info.return_value = [0, 10, 4]
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vol.storagePoolLookupByVolume.return_value.name.return_value = "pool"
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return vol
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p.get_volume_by_path = lookup
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return p
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class VolumeDetailsTestCase(unittest.TestCase):
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def test_inside_the_block_each_path_is_looked_up_once(self):
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p = volume_proxy({"/p/a.qcow2", "/p/b.raw"})
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with p.cached_reads():
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for _ in range(2):
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self.assertEqual(p._volume_details("/p/a.qcow2"), ("a.qcow2", 10, 4, "pool"))
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p._volume_details("/p/b.raw")
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self.assertIsNone(p._volume_details("/dev/sdx"))
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self.assertEqual(p.lookups, ["/p/a.qcow2", "/p/b.raw", "/dev/sdx"])
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def test_outside_the_block_and_after_a_change_the_volume_is_read_again(self):
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p = volume_proxy({"/p/a.qcow2"})
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p._volume_details("/p/a.qcow2")
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with p.cached_reads():
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p._volume_details("/p/a.qcow2")
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p._defineXML("<domain/>")
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p._volume_details("/p/a.qcow2")
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p._volume_details("/p/a.qcow2")
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self.assertEqual(len(p.lookups), 4)
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def disk(path, cache):
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return (
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f"<disk type='file' device='disk'><driver name='qemu' type='qcow2' cache='{cache}'/>"
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f"<source file='{path}'/><target dev='vda' bus='virtio'/></disk>"
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)
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class DiskListsTestCase(unittest.TestCase):
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"""The page lists the running and the persistent disks; both share a
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path's volume, each keeps its own settings."""
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def lists(self, live, config, volumes):
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p = volume_proxy(volumes)
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xml = {0: f"<domain><devices>{live}</devices></domain>", 3: f"<domain><devices>{config}</devices></domain>"}
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p.instance.XMLDesc = lambda flags: xml[flags]
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with p.cached_reads():
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return p, p.get_disk_devices(), p.get_disk_devices(config=True)
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def test_one_path_in_both_lists_is_looked_up_once(self):
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p, live, config = self.lists(disk("/p/a.qcow2", "none"), disk("/p/a.qcow2", "writeback"), {"/p/a.qcow2"})
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self.assertEqual(p.lookups, ["/p/a.qcow2"])
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self.assertEqual([(d["image"], d["storage"], d["size"], d["cache"]) for d in live], [("a.qcow2", "pool", 10, "none")])
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self.assertEqual([d["cache"] for d in config], ["writeback"])
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self.assertIsNot(live[0], config[0])
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def test_a_pending_disk_change_is_looked_up_on_its_own(self):
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p, live, config = self.lists(disk("/p/a.qcow2", "none"), disk("/p/b.qcow2", "none"), {"/p/a.qcow2", "/p/b.qcow2"})
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self.assertEqual(p.lookups, ["/p/a.qcow2", "/p/b.qcow2"])
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self.assertEqual((live[0]["image"], config[0]["image"]), ("a.qcow2", "b.qcow2"))
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def test_a_disk_outside_any_pool_shows_its_path(self):
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p, live, _ = self.lists(disk("/srv/x.img", "none"), disk("/srv/x.img", "none"), set())
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self.assertEqual(p.lookups, ["/srv/x.img"])
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self.assertEqual((live[0]["image"], live[0]["storage"], live[0]["size"]), ("/srv/x.img", None, None))
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