test: each app keeps its tests in a tests package

131 test modules sat next to the code they test; instances alone had
51 of them beside views.py and utils.py. They move into a
tests/ package per app, and the JavaScript checks into
webvirtcloud/tests/js. Each non-empty tests.py becomes tests/test_views.py;
the empty generated stubs are removed.

Imports of the app's own modules become absolute, paths built from
__file__ go one level up, the live helper is instances.tests.livetest,
and coverage omits */tests/*. The suite discovers the same 960 tests as
before.

vrtManager/test_host_reads.py

@@ -1,134 +0,0 @@
-"""A wvmConnect reads the host's info and capabilities once, and its domain
-capabilities once per emulator, arch, machine and domain type: the create
-page's getters parse the capabilities some 60 times, the overview reads the
-info four times. An object lives for one request. The interfaces page lists
-only the host's network devices, not all of them, and knows whether the host
-can change interfaces at all."""
-
-import unittest
-from unittest.mock import MagicMock
-
-from django.conf import settings
-
-if not settings.configured:
-    settings.configure(MAC_OUI="52:54:10")
-
-from libvirt import VIR_CONNECT_LIST_NODE_DEVICES_CAP_NET, VIR_ERR_NO_SUPPORT, VIR_ERR_OPERATION_DENIED, VIR_ERR_XML_ERROR, libvirtError
-from vrtManager.connection import wvmConnect
-from vrtManager.hostdetails import wvmHostDetails
-
-CAPABILITIES = """<capabilities><host><cpu><arch>x86_64</arch></cpu></host>
-<guest><os_type>hvm</os_type><arch name='x86_64'><emulator>/usr/bin/qemu-kvm</emulator>
-<machine>pc-q35-9.0</machine><machine canonical='pc-q35-9.0'>q35</machine><machine canonical='pc-i440fx-9.0'>pc</machine>
-<domain type='qemu'/><domain type='kvm'/></arch></guest></capabilities>"""
-
-
-class FakeConn:
-    def __init__(self):
-        self.reads = []
-
-    def getCapabilities(self):
-        self.reads.append("capabilities")
-        return CAPABILITIES
-
-    def getInfo(self):
-        self.reads.append("info")
-        return ["x86_64", 2048, 4, 0, 1, 2, 2, 1]
-
-    def getMemoryStats(self, cell, flags):
-        self.reads.append("memory")
-        return {"buffers": 0, "free": 1048576, "cached": 0}
-
-    def getHostname(self):
-        return "host"
-
-    def getSysinfo(self, flags):
-        return "<sysinfo/>"
-
-    def getURI(self):
-        return "qemu:///system"
-
-    def getDomainCapabilities(self, emulator, arch, machine, virttype):
-        self.reads.append((emulator, arch, machine, virttype))
-        return "<domainCapabilities/>"
-
-
-def connection(cls=wvmConnect):
-    conn = cls.__new__(cls)  # no libvirt connection: only these calls
-    conn.wvm = FakeConn()
-    return conn
-
-
-class CapabilitiesOnceTestCase(unittest.TestCase):
-    def test_the_capabilities_are_read_once_for_all_getters(self):
-        conn = connection()
-        for _ in range(2):
-            conn.get_emulator("x86_64")
-            conn.get_machine_types("x86_64")
-            conn.get_hypervisors_domain_types()
-            conn.get_cap_xml()
-        self.assertEqual(conn.wvm.reads, ["capabilities"])
-
-    def test_domain_capabilities_are_read_once_per_machine(self):
-        conn = connection()
-        for _ in range(2):
-            conn.get_dom_cap_xml("x86_64", "q35")
-            conn.get_dom_cap_xml("x86_64", "pc")
-            conn.get_dom_cap_xml("x86_64", "unknown")  # falls back to pc
-        self.assertEqual(
-            conn.wvm.reads,
-            ["capabilities", ("/usr/bin/qemu-kvm", "x86_64", "q35", "kvm"), ("/usr/bin/qemu-kvm", "x86_64", "pc", "kvm")],
-        )
-
-    def test_the_overview_reads_the_info_once_and_the_free_memory_each_time(self):
-        conn = connection(wvmHostDetails)
-        conn.get_node_info()
-        conn.get_memory_usage()
-        self.assertEqual(conn.get_memory_usage()["total"], 2048 * 1048576)
-        self.assertEqual(conn.wvm.reads, ["info", "memory", "memory"])
-
-    def test_two_objects_do_not_share_their_reads(self):
-        a, b = connection(), connection()
-        a.get_cap_xml()
-        b.get_cap_xml()
-        self.assertEqual((a.wvm.reads, b.wvm.reads), (["capabilities"], ["capabilities"]))
-
-    def test_a_failed_read_is_not_kept(self):
-        conn = connection()
-        conn.wvm.getCapabilities = lambda: (_ for _ in ()).throw(RuntimeError("libvirt error"))
-        with self.assertRaises(RuntimeError):
-            conn.get_cap_xml()
-        conn.wvm = FakeConn()
-        conn.get_cap_xml()
-        self.assertEqual(conn.wvm.reads, ["capabilities"])
-
-
-class NetDevicesTestCase(unittest.TestCase):
-    def test_only_the_network_devices_are_listed_and_read(self):
-        conn = connection()
-        devices = {
-            VIR_CONNECT_LIST_NODE_DEVICES_CAP_NET: [
-                MagicMock(**{"XMLDesc.return_value": f"<device><capability type='net'><interface>{name}</interface>"
-                                                     "<capability type='80203'/></capability></device>"})
-                for name in ("eth0", "br0")
-            ]
-        }
-        conn.wvm.listAllDevices = lambda flags: devices.get(flags, [])
-        self.assertEqual(conn.get_net_devices(), ["eth0", "br0"])
-
-
-class ChangeInterfacesTestCase(unittest.TestCase):
-    def error(self, code):
-        err = libvirtError("refused")
-        err.get_error_code = lambda: code
-        return err
-
-    def test_a_backend_without_define_cannot_change_interfaces(self):
-        conn = connection()
-        # any other refusal (access denied, ...) leaves the page as it was
-        for code, changeable in ((VIR_ERR_NO_SUPPORT, False), (VIR_ERR_XML_ERROR, True), (VIR_ERR_OPERATION_DENIED, True)):
-            with self.subTest(code=code):
-                conn.wvm.interfaceDefineXML = MagicMock(side_effect=self.error(code))
-                self.assertIs(conn.can_change_interfaces(), changeable)
-                # an invalid definition: nothing can be defined by asking
-                conn.wvm.interfaceDefineXML.assert_called_once_with("<interface/>", 0)