tests: Disallow use of util.subp except for where needed.

In many cases, cloud-init uses 'util.subp' to run a subprocess.
This is not really desirable in our unit tests as it makes the tests
dependent upon existance of those utilities.

The change here is to modify the base test case class (CiTestCase) to
raise exception any time subp is called.  Then, fix all callers.
For cases where subp is necessary or actually desired, we can use it
via
  a.) context hander CiTestCase.allow_subp(value)
  b.) class level self.allowed_subp = value

Both cases the value is a list of acceptable executable names that
will be called (essentially argv[0]).

Some cleanups in AltCloud were done as the code was being updated.

1 files changed, 18 insertions, 26 deletions

diff --git a/tests/unittests/test_datasource/test_altcloud.py b/tests/unittests/test_datasource/test_altcloud.py
index 3253f3ad..ff35904e 100644
--- a/tests/unittests/test_datasource/test_altcloud.py
+++ b/tests/unittests/test_datasource/test_altcloud.py
@@ -262,64 +262,56 @@ class TestUserDataRhevm(CiTestCase):
     '''
     Test to exercise method: DataSourceAltCloud.user_data_rhevm()
     '''
-    cmd_pass = ['true']
-    cmd_fail = ['false']
-    cmd_not_found = ['bogus bad command']
-
     def setUp(self):
         '''Set up.'''
         self.paths = helpers.Paths({'cloud_dir': '/tmp'})
-        self.mount_dir = tempfile.mkdtemp()
+        self.mount_dir = self.tmp_dir()
         _write_user_data_files(self.mount_dir, 'test user data')
-
-    def tearDown(self):
-        # Reset
-
-        _remove_user_data_files(self.mount_dir)
-
-        # Attempt to remove the temp dir ignoring errors
-        try:
-            shutil.rmtree(self.mount_dir)
-        except OSError:
-            pass
-
-        dsac.CLOUD_INFO_FILE = '/etc/sysconfig/cloud-info'
-        dsac.CMD_PROBE_FLOPPY = ['modprobe', 'floppy']
-        dsac.CMD_UDEVADM_SETTLE = ['udevadm', 'settle',
-                                   '--quiet', '--timeout=5']
+        self.add_patch(
+            'cloudinit.sources.DataSourceAltCloud.modprobe_floppy',
+            'm_modprobe_floppy', return_value=None)
+        self.add_patch(
+            'cloudinit.sources.DataSourceAltCloud.util.udevadm_settle',
+            'm_udevadm_settle', return_value=('', ''))
+        self.add_patch(
+            'cloudinit.sources.DataSourceAltCloud.util.mount_cb',
+            'm_mount_cb')
 
     def test_mount_cb_fails(self):
         '''Test user_data_rhevm() where mount_cb fails.'''
 
-        dsac.CMD_PROBE_FLOPPY = self.cmd_pass
+        self.m_mount_cb.side_effect = util.MountFailedError("Failed Mount")
         dsrc = dsac.DataSourceAltCloud({}, None, self.paths)
         self.assertEqual(False, dsrc.user_data_rhevm())
 
     def test_modprobe_fails(self):
         '''Test user_data_rhevm() where modprobe fails.'''
 
-        dsac.CMD_PROBE_FLOPPY = self.cmd_fail
+        self.m_modprobe_floppy.side_effect = util.ProcessExecutionError(
+            "Failed modprobe")
         dsrc = dsac.DataSourceAltCloud({}, None, self.paths)
         self.assertEqual(False, dsrc.user_data_rhevm())
 
     def test_no_modprobe_cmd(self):
         '''Test user_data_rhevm() with no modprobe command.'''
 
-        dsac.CMD_PROBE_FLOPPY = self.cmd_not_found
+        self.m_modprobe_floppy.side_effect = util.ProcessExecutionError(
+            "No such file or dir")
         dsrc = dsac.DataSourceAltCloud({}, None, self.paths)
         self.assertEqual(False, dsrc.user_data_rhevm())
 
     def test_udevadm_fails(self):
         '''Test user_data_rhevm() where udevadm fails.'''
 
-        dsac.CMD_UDEVADM_SETTLE = self.cmd_fail
+        self.m_udevadm_settle.side_effect = util.ProcessExecutionError(
+            "Failed settle.")
         dsrc = dsac.DataSourceAltCloud({}, None, self.paths)
         self.assertEqual(False, dsrc.user_data_rhevm())
 
     def test_no_udevadm_cmd(self):
         '''Test user_data_rhevm() with no udevadm command.'''
 
-        dsac.CMD_UDEVADM_SETTLE = self.cmd_not_found
+        self.m_udevadm_settle.side_effect = OSError("No such file or dir")
         dsrc = dsac.DataSourceAltCloud({}, None, self.paths)
         self.assertEqual(False, dsrc.user_data_rhevm())