1 files changed, 81 insertions, 0 deletions
diff --git a/nova/tests/fixtures/filesystem.py b/nova/tests/fixtures/filesystem.py
new file mode 100644
index 0000000000..932d42fe27
--- /dev/null
+++ b/nova/tests/fixtures/filesystem.py
@@ -0,0 +1,81 @@
+# Licensed under the Apache License, Version 2.0 (the "License"); you may
+# not use this file except in compliance with the License. You may obtain
+# a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+# License for the specific language governing permissions and limitations
+# under the License.
+
+import os
+import shutil
+import tempfile
+from unittest import mock
+
+import fixtures
+
+from nova import filesystem
+from nova.virt.libvirt.cpu import core
+
+
+SYS = 'sys'
+
+
+class TempFileSystemFixture(fixtures.Fixture):
+    """Creates a fake / filesystem"""
+
+    def _setUp(self):
+        self.temp_dir = tempfile.TemporaryDirectory(prefix='fake_fs')
+        # NOTE(sbauza): I/O disk errors may raise an exception here, as we
+        # don't ignore them. If that's causing a problem in our CI jobs, the
+        # recommended solution is to use shutil.rmtree instead of cleanup()
+        # with ignore_errors parameter set to True (or wait for the minimum
+        # python version to be 3.10 as TemporaryDirectory will provide
+        # ignore_cleanup_errors parameter)
+        self.addCleanup(self.temp_dir.cleanup)
+
+
+class SysFileSystemFixture(TempFileSystemFixture):
+    """Creates a fake /sys filesystem"""
+
+    def __init__(self, cpus_supported=None):
+        self.cpus_supported = cpus_supported or 10
+
+    def _setUp(self):
+        super()._setUp()
+        self.sys_path = os.path.join(self.temp_dir.name, SYS)
+        self.addCleanup(shutil.rmtree, self.sys_path, ignore_errors=True)
+
+        sys_patcher = mock.patch(
+            'nova.filesystem.SYS',
+            new_callable=mock.PropertyMock(return_value=self.sys_path))
+        self.sys_mock = sys_patcher.start()
+        self.addCleanup(sys_patcher.stop)
+
+        avail_path_patcher = mock.patch(
+            'nova.virt.libvirt.cpu.core.AVAILABLE_PATH',
+            new_callable=mock.PropertyMock(
+                return_value=os.path.join(self.sys_path,
+                                          'devices/system/cpu/present')))
+        self.avail_path_mock = avail_path_patcher.start()
+        self.addCleanup(avail_path_patcher.stop)
+
+        cpu_path_patcher = mock.patch(
+            'nova.virt.libvirt.cpu.core.CPU_PATH_TEMPLATE',
+            new_callable=mock.PropertyMock(
+                return_value=os.path.join(self.sys_path,
+                                          'devices/system/cpu/cpu%(core)s')))
+        self.cpu_path_mock = cpu_path_patcher.start()
+        self.addCleanup(cpu_path_patcher.stop)
+
+        for cpu_nr in range(self.cpus_supported):
+            cpu_dir = os.path.join(self.cpu_path_mock % {'core': cpu_nr})
+            os.makedirs(os.path.join(cpu_dir, 'cpufreq'))
+            filesystem.write_sys(
+                os.path.join(cpu_dir, 'cpufreq/scaling_governor'),
+                data='powersave')
+        filesystem.write_sys(core.AVAILABLE_PATH,
+                             f'0-{self.cpus_supported - 1}')