Check [whitebox]/hypervisors before using it

A devstack deployment will not set [whitebox]/hypervisors because the
host IPs are not known by the whitebox devstack plugin. Therefore,
instead of always using the [whitebox]/hypervisors option blindly,
this patch starts checking it for truthiness first. If false, we
fallback on using the hostname from the OS-EXT-SRV-ATTR:host field in
the show server response, or from the list hypervisors API. In a
devstack deployment, both of these should contain hostnames that are
resolvable and reachable from the machine running the tests.

This patch also reworks get_hypervisor_ip() to be cleaner.

Change-Id: I1a4430b6ee668bb34c847a63246a14b704185432

whitebox_tempest_plugin/api/compute/base.py

@@ -102,17 +102,27 @@ class BaseWhiteboxComputeTest(base.BaseV2ComputeAdminTest):
     def get_hypervisor_ip(self, server_id):
         server = self.servers_client.show_server(server_id)
         host = server['server']['OS-EXT-SRV-ATTR:host']
-        try:
+
+        if not CONF.whitebox.hypervisors:
+            # NOTE(artom) [whitebox]/hypervisors not being set means we're
+            # running against a devstack deployment and we can just use host
+            # directly.
+            return host
+
+        if host in CONF.whitebox.hypervisors:
             return CONF.whitebox.hypervisors[host]
-        except KeyError:
-            raise exceptions.MissingHypervisorException(server=server_id,
-                                                        host=host)
+
+        raise exceptions.MissingHypervisorException(server=server_id,
+                                                    host=host)
 
     def get_all_hypervisors(self):
         """Returns a list of all hypervisor IPs in the deployment. Assumes all
         are up and running.
         """
-        return CONF.whitebox.hypervisors.values()
+        if CONF.whitebox.hypervisors:
+            return CONF.whitebox.hypervisors.values()
+        hvs = self.hypervisor_client.list_hypervisors()['hypervisors']
+        return [hv['hypervisor_hostname'] for hv in hvs]
 
     def get_server_xml(self, server_id):
         hv_ip = self.get_hypervisor_ip(server_id)

whitebox_tempest_plugin/api/compute/test_cpu_pinning.py

@@ -325,11 +325,15 @@ class CPUThreadPolicyTest(BasePinningTest):
         """
         siblings = {}
 
-        try:
-            host_address = CONF.whitebox.hypervisors[host]
-        except KeyError:
-            raise exceptions.MissingHypervisorException(server="",
-                                                        host=host)
+        if CONF.whitebox.hypervisors:
+            try:
+                host_address = CONF.whitebox.hypervisors[host]
+            except KeyError:
+                raise exceptions.MissingHypervisorException(server="",
+                                                            host=host)
+        else:
+            host_address = host
+
         virshxml = clients.VirshXMLClient(host_address)
         capxml = virshxml.capabilities()
         root = ET.fromstring(capxml)