Fix SQLite locking issue on unit tests

stestr runs tests in parallel and this can cause issues with locking
when SQLite is not mocked out properly and gets used in a test.  This
patch just switches Storage to use :memory: so that locking does not
occur.

Closes-Bug: #1908282
Change-Id: Iaa1c7b78dee498e0cc6dc6fccf12e74f22225ecd
(cherry picked from commit 36ef217bc6)

unit_tests/test_actions.py

@@ -19,6 +19,8 @@ from unit_tests.test_utils import (
     get_default_config,
 )
 
+import charmhelpers.core.unitdata
+
 __default_config = get_default_config()
 # NOTE(freyes): the default 'distro' makes the test suite behave different
 # depending on where it's being executed
@@ -34,6 +36,12 @@ TO_PATCH = [
 
 class PauseTestCase(CharmTestCase):
 
+    @classmethod
+    def setUpClass(cls):
+        super().setUpClass()
+        charmhelpers.core.unitdata._KV = (
+            charmhelpers.core.unitdata.Storage(':memory:'))
+
     def setUp(self):
         super(PauseTestCase, self).setUp(
             actions,
@@ -50,6 +58,12 @@ class PauseTestCase(CharmTestCase):
 
 class ResumeTestCase(CharmTestCase):
 
+    @classmethod
+    def setUpClass(cls):
+        super().setUpClass()
+        charmhelpers.core.unitdata._KV = (
+            charmhelpers.core.unitdata.Storage(':memory:'))
+
     def setUp(self):
         super(ResumeTestCase, self).setUp(
             actions, [
@@ -65,6 +79,12 @@ class ResumeTestCase(CharmTestCase):
 
 class ClearUnitKnownhostCacheTestCase(CharmTestCase):
 
+    @classmethod
+    def setUpClass(cls):
+        super().setUpClass()
+        charmhelpers.core.unitdata._KV = (
+            charmhelpers.core.unitdata.Storage(':memory:'))
+
     @staticmethod
     def _relation_get(attribute=None, unit=None, rid=None):
         return {
@@ -153,6 +173,12 @@ class ClearUnitKnownhostCacheTestCase(CharmTestCase):
 
 class SyncComputeAvailabilityZonesTestCase(CharmTestCase):
 
+    @classmethod
+    def setUpClass(cls):
+        super().setUpClass()
+        charmhelpers.core.unitdata._KV = (
+            charmhelpers.core.unitdata.Storage(':memory:'))
+
     @staticmethod
     def _relation_get(attribute=None, unit=None, rid=None):
         return {
@@ -286,6 +312,12 @@ class SyncComputeAvailabilityZonesTestCase(CharmTestCase):
 
 class MainTestCase(CharmTestCase):
 
+    @classmethod
+    def setUpClass(cls):
+        super().setUpClass()
+        charmhelpers.core.unitdata._KV = (
+            charmhelpers.core.unitdata.Storage(':memory:'))
+
     def setUp(self):
         super(MainTestCase, self).setUp(
             actions,

unit_tests/test_actions_openstack_upgrade.py

@@ -15,6 +15,8 @@
 from mock import patch
 from unit_tests.test_utils import CharmTestCase
 
+import charmhelpers.core.unitdata
+
 import actions.openstack_upgrade as openstack_upgrade
 
 
@@ -29,6 +31,12 @@ TO_PATCH = [
 
 class TestNovaCCUpgradeActions(CharmTestCase):
 
+    @classmethod
+    def setUpClass(cls):
+        super().setUpClass()
+        charmhelpers.core.unitdata._KV = (
+            charmhelpers.core.unitdata.Storage(':memory:'))
+
     def setUp(self):
         super(TestNovaCCUpgradeActions, self).setUp(openstack_upgrade,
                                                     TO_PATCH)

unit_tests/test_nova_cc_contexts.py

@@ -19,6 +19,8 @@ import hooks.nova_cc_context as context
 
 from charmhelpers.contrib.openstack import neutron
 from charmhelpers.contrib.openstack import utils
+import charmhelpers.core.unitdata
+
 from unit_tests.test_utils import CharmTestCase
 
 TO_PATCH = [
@@ -41,6 +43,13 @@ def fake_log(msg, level=None):
 
 
 class NovaComputeContextTests(CharmTestCase):
+
+    @classmethod
+    def setUpClass(cls):
+        super().setUpClass()
+        charmhelpers.core.unitdata._KV = (
+            charmhelpers.core.unitdata.Storage(':memory:'))
+
     def setUp(self):
         super(NovaComputeContextTests, self).setUp(context, TO_PATCH)
         self.relation_get.side_effect = self.test_relation.get

unit_tests/test_nova_cc_hooks.py

@@ -19,6 +19,7 @@ import tempfile
 from unit_tests.test_utils import CharmTestCase
 
 import charmhelpers.contrib.hardening.harden as harden
+import charmhelpers.core.unitdata
 
 import hooks.nova_cc_utils as utils
 import hooks.nova_cc_hooks as hooks
@@ -96,6 +97,12 @@ FAKE_KS_AUTH_CFG = {
 
 class NovaCCHooksTests(CharmTestCase):
 
+    @classmethod
+    def setUpClass(cls):
+        super().setUpClass()
+        charmhelpers.core.unitdata._KV = (
+            charmhelpers.core.unitdata.Storage(':memory:'))
+
     def setUp(self):
         super(NovaCCHooksTests, self).setUp(hooks, TO_PATCH)
         (tmpfd, hooks.NOVA_CONSOLEAUTH_OVERRIDE) = tempfile.mkstemp()

unit_tests/test_nova_cc_utils.py

@@ -16,6 +16,8 @@ from collections import OrderedDict
 from mock import patch, MagicMock, call
 import subprocess
 
+import charmhelpers.core.unitdata
+
 from unit_tests.test_utils import (
     CharmTestCase,
     patch_open,
@@ -247,6 +249,12 @@ NM_CELLS_LIST = b"""
 
 class NovaCCUtilsTests(CharmTestCase):
 
+    @classmethod
+    def setUpClass(cls):
+        super().setUpClass()
+        charmhelpers.core.unitdata._KV = (
+            charmhelpers.core.unitdata.Storage(':memory:'))
+
     def setUp(self):
         super(NovaCCUtilsTests, self).setUp(utils, TO_PATCH)
         self.config.side_effect = self.test_config.get