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/tests/test_change_network.py

@@ -0,0 +1,80 @@
+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 libvirtError
+from vrtManager.instance import wvmInstance
+
+DOMAIN_XML = """<domain><devices>
+<interface type='network'><mac address='52:54:00:00:00:01'/><source network='default'/><model type='virtio'/></interface>
+<interface type='network'><mac address='52:54:00:00:00:02'/><source network='default'/><model type='virtio'/>
+<bandwidth><outbound average='1000'/></bandwidth><link state='down'/>
+<address type='pci' domain='0x0000' bus='0x02' slot='0x00' function='0x0'/></interface>
+</devices></domain>"""
+
+
+def stopped_instance():
+    inst = wvmInstance.__new__(wvmInstance)
+    inst.instance = MagicMock()
+    inst.wvm = MagicMock()
+    inst._XMLDesc = MagicMock(return_value=DOMAIN_XML)
+    inst.get_status = MagicMock(return_value=5)
+    return inst
+
+
+class TestChangeNetwork(unittest.TestCase):
+    def test_edits_the_nic_in_place_and_keeps_its_other_settings(self):
+        from lxml import etree
+
+        inst = stopped_instance()
+        inst.change_network("52:54:00:00:00:02", "52:54:00:00:00:03", "br0", "bridge", "e1000", "clean-traffic")
+
+        defined = etree.fromstring(inst.wvm.defineXML.call_args[0][0])
+        first, second = defined.findall("devices/interface")
+        self.assertEqual(first.find("mac").get("address"), "52:54:00:00:00:01")
+        self.assertEqual(second.get("type"), "bridge")
+        self.assertEqual(second.find("mac").get("address"), "52:54:00:00:00:03")
+        self.assertEqual(second.find("source").attrib, {"bridge": "br0"})
+        self.assertEqual(second.find("model").get("type"), "e1000")
+        self.assertEqual(second.find("filterref").get("filter"), "clean-traffic")
+        # QoS, link state and the PCI address survive
+        self.assertEqual(second.find("bandwidth/outbound").get("average"), "1000")
+        self.assertEqual(second.find("link").get("state"), "down")
+        self.assertEqual(second.find("address").get("bus"), "0x02")
+
+    def test_unknown_old_mac_changes_nothing(self):
+        inst = stopped_instance()
+        with self.assertRaises(libvirtError):
+            inst.change_network("52:54:00:00:00:09", "52:54:00:00:00:03", "default", "net", "virtio", "")
+        inst.wvm.defineXML.assert_not_called()
+
+
+class TestAddNetworkXml(unittest.TestCase):
+    def attached(self, **kwargs):
+        from lxml import etree
+
+        inst = stopped_instance()
+        inst.add_network(**kwargs)
+        return etree.fromstring(inst.instance.attachDeviceFlags.call_args[0][0])
+
+    def test_posted_values_cannot_inject_elements(self):
+        iface = self.attached(
+            mac_address="52:54:00:00:00:05",
+            source="default",
+            model="virtio'/><filesystem type='mount'/><model type='x",
+            nwfilter="f'/><evil/>",
+        )
+        self.assertEqual([el.tag for el in iface], ["mac", "source", "model", "filterref"])
+        self.assertEqual(iface.find("model").get("type"), "virtio'/><filesystem type='mount'/><model type='x")
+
+    def test_missing_mac_is_left_to_libvirt(self):
+        iface = self.attached(mac_address="", source="default")
+        self.assertIsNone(iface.find("mac"))
+
+
+if __name__ == "__main__":
+    unittest.main()