Merge ~mpontillo/maas:backport-stats-test-fixes--2.3 into maas:2.3

[Mike Pontillo]

Fix random failures in test_stats.py.

[Mike Pontillo (mpontillo)]

Self-approve backport.

review: Approve

diff --git a/src/maasserver/stats.py b/src/maasserver/stats.py
index f6da73e..978af87 100644
--- a/src/maasserver/stats.py
+++ b/src/maasserver/stats.py
@@ -30,16 +30,20 @@ from maasserver.utils import get_maas_user_agent
 import requests
 
 
-def get_maas_stats():
+def get_machine_stats():
     nodes = Node.objects.all()
     machines = nodes.filter(node_type=NODE_TYPE.MACHINE)
     # Rather overall amount of stats for machines.
-    stats = machines.aggregate(
+    return machines.aggregate(
         total_cpu=Sum('cpu_count'), total_mem=Sum('memory'),
         total_storage=Sum('blockdevice__size'))
+
+
+def get_maas_stats():
     # Get all node types to get count values
     node_types = Node.objects.values_list('node_type', flat=True)
     node_types = Counter(node_types)
+    stats = get_machine_stats()
 
     return json.dumps({
         "controllers": {
diff --git a/src/maasserver/tests/test_stats.py b/src/maasserver/tests/test_stats.py
index 2bb0e1a..43aae70 100644
--- a/src/maasserver/tests/test_stats.py
+++ b/src/maasserver/tests/test_stats.py
@@ -13,6 +13,7 @@ from maasserver import stats
 from maasserver.models import Config
 from maasserver.stats import (
     get_maas_stats,
+    get_machine_stats,
     get_request_params,
     make_maas_user_agent_request,
 )
@@ -40,12 +41,18 @@ class TestMAASStats(MAASServerTestCase):
         factory.make_RegionRackController()
         factory.make_RegionController()
         factory.make_RackController()
-        m1 = factory.make_Machine(cpu_count=2, memory=200)
-        m2 = factory.make_Machine(cpu_count=3, memory=100)
+        factory.make_Machine(cpu_count=2, memory=200)
+        factory.make_Machine(cpu_count=3, memory=100)
         factory.make_Device()
 
         stats = get_maas_stats()
-        total_storage = int((m1.storage + m2.storage) * 1000000)
+        machine_stats = get_machine_stats()
+
+        # Due to floating point calculation subtleties, sometimes the value the
+        # database returns is off by one compared to the value Python
+        # calculates, so just get it directly from the database for the test.
+        total_storage = machine_stats['total_storage']
+
         compare = {
             "controllers": {
                 "regionracks": 1,