diff --git a/drivers/blktap2.py b/drivers/blktap2.py
index de4eb3570..16a05c5e3 100755
--- a/drivers/blktap2.py
+++ b/drivers/blktap2.py
@@ -162,6 +162,14 @@ def __getattr__(self, key):
             if self.info.has_key(key): return self.info[key]
             return object.__getattribute__(self, key)
 
+        @property
+        def has_status(self):
+            return 'status' in self.info
+
+        @property
+        def has_signal(self):
+            return 'signal' in self.info
+
         # Retrieves the error code returned by the command. If the error code
         # was not supplied at object-construction time, zero is returned.
         def get_error_code(self):
@@ -185,55 +193,6 @@ def _mkcmd(cls, args):
 
         return __next_mkcmd(args)
 
-    @classmethod
-    def failwith(cls, status, prev=False):
-        """
-        Fail next invocation with @status. If @prev is true, execute
-        the original command
-        """
-
-        __prev_mkcmd = cls.__next_mkcmd
-
-        @classmethod
-        def __mkcmd(cls, args):
-            if prev:
-                cmd = __prev_mkcmd(args)
-                cmd = "'%s' && exit %d" % ("' '".join(cmd), status)
-            else:
-                cmd = "exit %d" % status
-
-            return [ '/bin/sh', '-c', cmd  ]
-
-        cls.__next_mkcmd = __mkcmd
-
-    __strace_n = 0
-
-    @classmethod
-    def strace(cls):
-        """
-        Run next invocation through strace.
-        Output goes to /tmp/tap-ctl.<sm-pid>.<n>; <n> counts invocations.
-        """
-
-        __prev_mkcmd = cls.__next_mkcmd
-
-        @classmethod
-        def __next_mkcmd(cls, args):
-
-            # pylint: disable = E1101
-
-            cmd = __prev_mkcmd(args)
-
-            tracefile = "/tmp/%s.%d.%d" % (os.path.basename(cls.PATH),
-                                           os.getpid(),
-                                           cls.__strace_n)
-            cls.__strace_n += 1
-
-            return \
-                [ '/usr/bin/strace', '-o', tracefile, '--'] + cmd
-
-        cls.__next_mkcmd = __next_mkcmd
-
     @classmethod
     def _call(cls, args, quiet = False, input = None):
         """
@@ -351,7 +310,7 @@ def list(cls, **args):
 
         except cls.CommandFailure, e:
             transient = [ errno.EPROTO, errno.ENOENT ]
-            if e.status in transient:
+            if e.has_status and e.status in transient:
                 raise RetryLoop.TransientFailure(e)
             raise
 
@@ -389,6 +348,12 @@ def detach(cls, pid, minor):
         args = [ "detach", "-p", pid, "-m", minor ]
         cls._pread(args)
 
+    @classmethod
+    def _load_key(cls, key_hash, vdi_uuid):
+        import plugins
+
+        return plugins.load_key(key_hash, vdi_uuid)
+
     @classmethod
     def open(cls, pid, minor, _type, _file, options):
         params = Tapdisk.Arg(_type, _file)
@@ -414,11 +379,10 @@ def open(cls, pid, minor, _type, _file, options):
         if options.get('cbtlog'):
             args.extend(['-C', options['cbtlog']])
         if options.get('key_hash'):
-            import plugins
-
             key_hash = options['key_hash']
             vdi_uuid = options['vdi_uuid']
-            key = plugins.load_key(key_hash, vdi_uuid)
+            key = cls._load_key(key_hash, vdi_uuid)
+
             if not key:
                 raise util.SMException("No key found with key hash {}".format(key_hash))
             input = key
diff --git a/tests/test_blktap2.py b/tests/test_blktap2.py
index 21bf5f1cf..27bc53d34 100644
--- a/tests/test_blktap2.py
+++ b/tests/test_blktap2.py
@@ -1,9 +1,14 @@
+import errno
+import json
+from StringIO import StringIO
+import subprocess
 import unittest
-import blktap2
 import mock
-import testlib
 import os
 
+import blktap2
+import testlib
+import util
 
 class TestVDI(unittest.TestCase):
     # This can't use autospec as vdi is created in __init__
@@ -51,3 +56,629 @@ def test_linknbd(self, nbd_link2, nbd_link):
         nbd_link2.mklink.assert_called_with(expected_path)
 
 
+class TestTapCtl(unittest.TestCase):
+
+    def setUp(self):
+        subprocess_patcher = mock.patch("blktap2.subprocess")
+        self.mock_subprocess = subprocess_patcher.start()
+
+        log_patcher = mock.patch('blktap2.util.SMlog', autospec=True)
+        self.mock_log = log_patcher.start()
+        self.mock_log.side_effect = self.log
+
+        self.addCleanup(mock.patch.stopall)
+
+    def log(self, message):
+        print message
+
+    def test_list_no_args(self):
+        """
+        TapCtl list no args
+        """
+        mock_process = mock.MagicMock(autospec='subprocess.Popen')
+        mock_process.stdout = StringIO(
+            "pid=705 minor=0 state=0 args=vhd:/dev/VG_XenStorage-2eeb9fd5-6545-8f0b-cf72-0378e413a31c/VHD-a7c0f37e-b7fb-4a44-a6fe-05067fb84c09")
+        mock_process.wait.return_value = 0
+        self.mock_subprocess.Popen.return_value = mock_process
+
+        results = blktap2.TapCtl.list()
+
+        self.mock_subprocess.Popen.assert_called_with(
+            ['/usr/sbin/tap-ctl', 'list'],
+            close_fds=True, stdin=mock.ANY,
+            stdout=mock.ANY, stderr=mock.ANY)
+        self.assertEqual(1, len(results))
+        self.assertEqual(705, results[0]['pid'])
+        self.assertEqual(0, results[0]['minor'])
+        self.assertEqual(0, results[0]['state'])
+        self.assertEqual('vhd:/dev/VG_XenStorage-2eeb9fd5-6545-8f0b-cf72-0378e413a31c/VHD-a7c0f37e-b7fb-4a44-a6fe-05067fb84c09',
+                         results[0]['args'])
+
+    def test_list_pid_arg(self):
+        """
+        TapCtl list pid arg
+        """
+        mock_process = mock.MagicMock(autospec='subprocess.Popen')
+        mock_process.stdout = StringIO("")
+        mock_process.wait.return_value = 0
+        self.mock_subprocess.Popen.return_value = mock_process
+
+        attrs = {"pid": 705}
+
+        results = blktap2.TapCtl.list(**attrs)
+
+        self.assertEqual(0, len(results))
+        self.assertEqual(1, self.mock_subprocess.Popen.call_count)
+        self.assertIn('-p 705', ' '.join(
+            self.mock_subprocess.Popen.call_args[0][0]))
+
+    def test_list_retry_eproto(self):
+        """
+        TapCtl list retry on eproto
+        """
+        mock_process1 = mock.MagicMock(autospec='subprocess.Popen')
+        mock_process1.stdout = StringIO("")
+        mock_process1.wait.return_value = errno.EPROTO
+        mock_process2 = mock.MagicMock(autospec='subprocess.Popen')
+        mock_process2.stdout = StringIO("")
+        mock_process2.wait.return_value = 0
+
+        self.mock_subprocess.Popen.side_effect = [
+            mock_process1, mock_process2]
+
+        results = blktap2.TapCtl.list()
+
+        self.assertEqual(0, len(results))
+        self.assertEqual(2, self.mock_subprocess.Popen.call_count)
+
+    def test_list_eperm_failure(self):
+        """
+        TapCtl list failure on eperm
+        """
+        mock_process1 = mock.MagicMock(autospec='subprocess.Popen')
+        mock_process1.stdout = StringIO("")
+        mock_process1.wait.return_value = errno.EPERM
+
+        self.mock_subprocess.Popen.side_effect = [
+            mock_process1]
+
+        with self.assertRaises(blktap2.TapCtl.CommandFailure) as cf:
+            blktap2.TapCtl.list()
+
+        self.assertTrue(cf.exception.has_status)
+
+    def test_list_signalled(self):
+        """
+        TapCtl list, exited signalled
+        """
+        mock_process1 = mock.MagicMock(autospec='subprocess.Popen')
+        mock_process1.stdout = StringIO("")
+        mock_process1.wait.return_value = -11
+
+        self.mock_subprocess.Popen.side_effect = [
+            mock_process1]
+
+        with self.assertRaises(blktap2.TapCtl.CommandFailure) as cf:
+            blktap2.TapCtl.list()
+
+        self.assertTrue(cf.exception.has_signal)
+
+    def test_allocate_no_path(self):
+        """
+        TapCtl allocate
+        """
+        mock_process = mock.MagicMock(autospec='subprocess.Popen')
+        mock_process.stdout = StringIO('/dev/xen/blktap-2/tapdev1')
+        mock_process.wait.return_value = 0
+        self.mock_subprocess.Popen.side_effect = [mock_process]
+
+        results = blktap2.TapCtl.allocate()
+
+        self.mock_subprocess.Popen.assert_called_with(
+            ['/usr/sbin/tap-ctl', 'allocate'],
+            close_fds=True, stdin=mock.ANY,
+            stdout=mock.ANY, stderr=mock.ANY)
+        self.assertEqual('/dev/xen/blktap-2/tapdev1',
+                         results)
+
+    def test_free(self):
+        """
+        TapCtl free
+        """
+        mock_process = mock.MagicMock(autospec='subprocess.Popen')
+        mock_process.stdout = StringIO('')
+        mock_process.wait.return_value = 0
+        self.mock_subprocess.Popen.side_effect = [mock_process]
+
+        blktap2.TapCtl.free(1)
+
+        self.mock_subprocess.Popen.assert_called_with(
+            ['/usr/sbin/tap-ctl', 'free', '-m', '1'],
+            close_fds=True, stdin=mock.ANY,
+            stdout=mock.ANY, stderr=mock.ANY)
+
+    def test_spawn(self):
+        """
+        TapCtl spawn
+        """
+        mock_process = mock.MagicMock(autospec='subprocess.Popen')
+        mock_process.stdout = StringIO('22127')
+        mock_process.wait.return_value = 0
+        self.mock_subprocess.Popen.side_effect = [mock_process]
+
+        pid = blktap2.TapCtl.spawn()
+
+        self.mock_subprocess.Popen.assert_called_with(
+            ['/usr/sbin/tap-ctl', 'spawn'],
+            close_fds=True, stdin=mock.ANY,
+            stdout=mock.ANY, stderr=mock.ANY)
+
+        self.assertEqual(22127, pid)
+
+    def test_spawn_retry_on_eperm(self):
+        """
+        TapCtl spawn, retry (CA-292268)
+        """
+        mock_process1 = mock.MagicMock(autospec='subprocess.Popen')
+        mock_process1.stdout = StringIO('')
+        mock_process1.wait.return_value = errno.EPERM
+        mock_process2 = mock.MagicMock(autospec='subprocess.Popen')
+        mock_process2.stdout = StringIO('22127')
+        mock_process2.wait.return_value = 0
+        self.mock_subprocess.Popen.side_effect = [
+            mock_process1, mock_process2]
+
+        pid = blktap2.TapCtl.spawn()
+
+        self.mock_subprocess.Popen.assert_called_with(
+            ['/usr/sbin/tap-ctl', 'spawn'],
+            close_fds=True, stdin=mock.ANY,
+            stdout=mock.ANY, stderr=mock.ANY)
+
+        self.assertEqual(22127, pid)
+
+    def test_spawn_fail_on_error(self):
+        """
+        TapCtl spawn, command failure
+        """
+        mock_process = mock.MagicMock(autospec='subprocess.Popen')
+        mock_process.stdout = StringIO('')
+        mock_process.wait.return_value = errno.EIO
+        self.mock_subprocess.Popen.side_effect = [mock_process]
+
+        with self.assertRaises(blktap2.TapCtl.CommandFailure) as cf:
+            blktap2.TapCtl.spawn()
+
+        self.assertEqual(errno.EIO, cf.exception.status)
+
+    def test_attach(self):
+        """
+        TapCtl attach
+        """
+        mock_process = mock.MagicMock(autospec='subprocess.Popen')
+        mock_process.stdout = StringIO('')
+        mock_process.wait.return_value = 0
+        self.mock_subprocess.Popen.side_effect = [mock_process]
+
+        blktap2.TapCtl.attach(22127, 2)
+
+        self.assertEqual(1, self.mock_subprocess.Popen.call_count)
+        proc_args = ' '.join(self.mock_subprocess.Popen.call_args[0][0])
+        self.assertIn('/usr/sbin/tap-ctl attach', proc_args)
+        self.assertIn('-p 22127', proc_args)
+        self.assertIn('-m 2', proc_args)
+
+    def test_detach(self):
+        """
+        TapCtl detach
+        """
+        mock_process = mock.MagicMock(autospec='subprocess.Popen')
+        mock_process.stdout = StringIO('')
+        mock_process.wait.return_value = 0
+        self.mock_subprocess.Popen.side_effect = [mock_process]
+
+        blktap2.TapCtl.detach(22127, 2)
+
+        self.assertEqual(1, self.mock_subprocess.Popen.call_count)
+        proc_args = ' '.join(self.mock_subprocess.Popen.call_args[0][0])
+        self.assertIn('/usr/sbin/tap-ctl detach', proc_args)
+        self.assertIn('-p 22127', proc_args)
+        self.assertIn('-m 2', proc_args)
+
+    def test_close(self):
+        """
+        Tapctl close
+        """
+        mock_process = mock.MagicMock(autospec='subprocess.Popen')
+        mock_process.stdout = StringIO('')
+        mock_process.wait.return_value = 0
+        self.mock_subprocess.Popen.side_effect = [mock_process]
+
+        blktap2.TapCtl.close(22127, 2)
+
+        self.assertEqual(1, self.mock_subprocess.Popen.call_count)
+        proc_args = ' '.join(self.mock_subprocess.Popen.call_args[0][0])
+        self.assertIn('/usr/sbin/tap-ctl close', proc_args)
+        self.assertIn('-p 22127', proc_args)
+        self.assertIn('-m 2', proc_args)
+        # Close should have a timeout
+        self.assertIn('-t 30', proc_args)
+        # Not forced
+        self.assertNotIn('-f', proc_args)
+
+    def test_close_force(self):
+        """
+        Tapctl close, forced
+        """
+        mock_process = mock.MagicMock(autospec='subprocess.Popen')
+        mock_process.stdout = StringIO('')
+        mock_process.wait.return_value = 0
+        self.mock_subprocess.Popen.side_effect = [mock_process]
+
+        blktap2.TapCtl.close(22127, 2, force=True)
+
+        self.assertEqual(1, self.mock_subprocess.Popen.call_count)
+        proc_args = ' '.join(self.mock_subprocess.Popen.call_args[0][0])
+        self.assertIn('/usr/sbin/tap-ctl close', proc_args)
+        self.assertIn('-p 22127', proc_args)
+        self.assertIn('-m 2', proc_args)
+        # Close should have a timeout
+        self.assertIn('-t 30', proc_args)
+        # Forced
+        self.assertIn('-f', proc_args)
+
+    def test_pause(self):
+        """
+        TapCtl pause
+        """
+        mock_process = mock.MagicMock(autospec='subprocess.Popen')
+        mock_process.stdout = StringIO('')
+        mock_process.wait.return_value = 0
+        self.mock_subprocess.Popen.side_effect = [mock_process]
+
+        blktap2.TapCtl.pause(22127, 2)
+
+        self.assertEqual(1, self.mock_subprocess.Popen.call_count)
+        proc_args = ' '.join(self.mock_subprocess.Popen.call_args[0][0])
+        self.assertIn('/usr/sbin/tap-ctl pause', proc_args)
+        self.assertIn('-p 22127', proc_args)
+        self.assertIn('-m 2', proc_args)
+
+    def test_unpause(self):
+        """
+        TapCtl unpause
+        """
+        mock_process = mock.MagicMock(autospec='subprocess.Popen')
+        mock_process.stdout = StringIO('')
+        mock_process.wait.return_value = 0
+        self.mock_subprocess.Popen.side_effect = [mock_process]
+
+        blktap2.TapCtl.unpause(
+            22127, 2, _type='vhd',
+            _file='/dev/VG_XenStorage-2eeb9fd5-6545-8f0b-cf72-'
+            '0378e413a31c/VHD-a7c0f37e-b7fb-4a44-a6fe-05067fb84c09.vhd')
+
+        self.assertEqual(1, self.mock_subprocess.Popen.call_count)
+        proc_args = ' '.join(self.mock_subprocess.Popen.call_args[0][0])
+        self.assertIn('/usr/sbin/tap-ctl unpause', proc_args)
+        self.assertIn('-p 22127', proc_args)
+        self.assertIn('-m 2', proc_args)
+        self.assertIn('-a vhd:/dev/VG_XenStorage-2eeb9fd5-6545-8f0b-cf72-'
+                      '0378e413a31c/VHD-a7c0f37e-b7fb-4a44-a6fe-'
+                      '05067fb84c09.vhd',
+                      proc_args)
+
+    def test_unpause_mirror(self):
+        """
+        TapCtl unpause, mirroring
+        """
+        mock_process = mock.MagicMock(autospec='subprocess.Popen')
+        mock_process.stdout = StringIO('')
+        mock_process.wait.return_value = 0
+        self.mock_subprocess.Popen.side_effect = [mock_process]
+
+        blktap2.TapCtl.unpause(22127, 2, mirror='nbd:mirror_vbd/10/xvda')
+
+        self.assertEqual(1, self.mock_subprocess.Popen.call_count)
+        proc_args = ' '.join(self.mock_subprocess.Popen.call_args[0][0])
+        self.assertIn('/usr/sbin/tap-ctl unpause', proc_args)
+        self.assertIn('-p 22127', proc_args)
+        self.assertIn('-m 2', proc_args)
+        self.assertIn('-2 nbd:mirror_vbd/10/xvda', proc_args)
+
+    def test_unpause_cbtlog(self):
+        """
+        TapCtl unpause, CBT logging
+        """
+        mock_process = mock.MagicMock(autospec='subprocess.Popen')
+        mock_process.stdout = StringIO('')
+        mock_process.wait.return_value = 0
+        self.mock_subprocess.Popen.side_effect = [mock_process]
+
+        blktap2.TapCtl.unpause(
+            22127, 2,
+            cbtlog='/dev/VG_XenStorage-9bf5335b-7fef-298c-109c-'
+            '1d12e931edfd/b76f0618-4dad-4b15-825f-b0b0fb006d67.cbtlog')
+
+        self.assertEqual(1, self.mock_subprocess.Popen.call_count)
+        proc_args = ' '.join(self.mock_subprocess.Popen.call_args[0][0])
+        self.assertIn('/usr/sbin/tap-ctl unpause', proc_args)
+        self.assertIn('-p 22127', proc_args)
+        self.assertIn('-m 2', proc_args)
+        self.assertIn('-c /dev/VG_XenStorage-9bf5335b-7fef-298c-109c-'
+                      '1d12e931edfd/b76f0618-4dad-4b15-825f'
+                      '-b0b0fb006d67.cbtlog',
+                      proc_args)
+
+    def test_open(self):
+        """
+        TapCtl open
+        """
+        mock_process = mock.MagicMock(autospec='subprocess.Popen')
+        mock_process.stdout = StringIO('')
+        mock_process.wait.return_value = 0
+        self.mock_subprocess.Popen.side_effect = [mock_process]
+
+        options = {'timeout': 40}
+
+        blktap2.TapCtl.open(
+            22127, 2, 'vhd', '/dev/VG_XenStorage-2eeb9fd5-6545-8f0b-cf72-'
+            '0378e413a31c/VHD-a7c0f37e-b7fb-4a44-a6fe-05067fb84c09.vhd', options)
+
+        self.assertEqual(1, self.mock_subprocess.Popen.call_count)
+        proc_args = ' '.join(self.mock_subprocess.Popen.call_args[0][0])
+        self.assertIn('/usr/sbin/tap-ctl open', proc_args)
+        self.assertIn('-p 22127', proc_args)
+        self.assertIn('-m 2', proc_args)
+        self.assertIn('-a vhd:/dev/VG_XenStorage-2eeb9fd5-6545-8f0b-cf72-'
+            '0378e413a31c/VHD-a7c0f37e-b7fb-4a44-a6fe-05067fb84c09.vhd',
+                      proc_args)
+        self.assertIn('-t 40', proc_args)
+
+    def test_open_readonly(self):
+        """
+        TapCtl open, readonly
+        """
+        mock_process = mock.MagicMock(autospec='subprocess.Popen')
+        mock_process.stdout = StringIO('')
+        mock_process.wait.return_value = 0
+        self.mock_subprocess.Popen.side_effect = [mock_process]
+
+        options = {'rdonly': True}
+
+        blktap2.TapCtl.open(
+            22127, 2, 'vhd', '/dev/VG_XenStorage-2eeb9fd5-6545-8f0b-cf72-'
+            '0378e413a31c/VHD-a7c0f37e-b7fb-4a44-a6fe-05067fb84c09.vhd', options)
+
+        self.assertEqual(1, self.mock_subprocess.Popen.call_count)
+        proc_args = ' '.join(self.mock_subprocess.Popen.call_args[0][0])
+        self.assertIn('/usr/sbin/tap-ctl open', proc_args)
+        self.assertIn('-R', proc_args)
+
+    def test_open_secondary(self):
+        """
+        TapCtl open, readonly
+        """
+        mock_process = mock.MagicMock(autospec='subprocess.Popen')
+        mock_process.stdout = StringIO('')
+        mock_process.wait.return_value = 0
+        self.mock_subprocess.Popen.side_effect = [mock_process]
+
+        options = {'secondary': 'nbd:mirror_vbd/10/xvda'}
+
+        blktap2.TapCtl.open(
+            22127, 2, 'vhd', '/dev/VG_XenStorage-2eeb9fd5-6545-8f0b-cf72-'
+            '0378e413a31c/VHD-a7c0f37e-b7fb-4a44-a6fe-05067fb84c09.vhd', options)
+
+        self.assertEqual(1, self.mock_subprocess.Popen.call_count)
+        proc_args = ' '.join(self.mock_subprocess.Popen.call_args[0][0])
+        self.assertIn('/usr/sbin/tap-ctl open', proc_args)
+        self.assertIn('-2 nbd:mirror_vbd/10/xvda', proc_args)
+
+    def test_open_read_cache(self):
+        """
+        TapCtl open, read cache
+        """
+        mock_process = mock.MagicMock(autospec='subprocess.Popen')
+        mock_process.stdout = StringIO('')
+        mock_process.wait.return_value = 0
+        self.mock_subprocess.Popen.side_effect = [mock_process]
+
+        options = {'o_direct': False}
+
+        blktap2.TapCtl.open(
+            22127, 2, 'vhd', '/dev/VG_XenStorage-2eeb9fd5-6545-8f0b-cf72-'
+            '0378e413a31c/VHD-a7c0f37e-b7fb-4a44-a6fe-05067fb84c09.vhd', options)
+
+        self.assertEqual(1, self.mock_subprocess.Popen.call_count)
+        proc_args = ' '.join(self.mock_subprocess.Popen.call_args[0][0])
+        self.assertIn('/usr/sbin/tap-ctl open', proc_args)
+        self.assertIn('-D', proc_args)
+
+    def test_open_intellicache_leaf(self):
+        """
+        TapCtl open, intellicache leaf
+        """
+        mock_process = mock.MagicMock(autospec='subprocess.Popen')
+        mock_process.stdout = StringIO('')
+        mock_process.wait.return_value = 0
+        self.mock_subprocess.Popen.side_effect = [mock_process]
+
+        options = {
+            'rdonly': False,
+            'lcache': False,
+            'existing_prt': 4,
+            'secondary': None,
+            'standby': False
+        }
+
+        blktap2.TapCtl.open(
+            22127, 2, 'vhd', '/dev/VG_XenStorage-2eeb9fd5-6545-8f0b-cf72-'
+            '0378e413a31c/VHD-a7c0f37e-b7fb-4a44-a6fe-05067fb84c09.vhd', options)
+
+        self.assertEqual(1, self.mock_subprocess.Popen.call_count)
+        proc_args = ' '.join(self.mock_subprocess.Popen.call_args[0][0])
+        self.assertIn('/usr/sbin/tap-ctl open', proc_args)
+        self.assertIn('-e 4', proc_args)
+
+    def test_open_intellicache_leaf_non_persist(self):
+        """
+        TapCtl open, intellicache leaf, non-persistent
+        """
+        mock_process = mock.MagicMock(autospec='subprocess.Popen')
+        mock_process.stdout = StringIO('')
+        mock_process.wait.return_value = 0
+        self.mock_subprocess.Popen.side_effect = [mock_process]
+
+        options = {
+            'rdonly': False,
+            'lcache': False,
+            'existing_prt': 4,
+            'secondary': None,
+            'standby': True
+        }
+
+        blktap2.TapCtl.open(
+            22127, 2, 'vhd', '/dev/VG_XenStorage-2eeb9fd5-6545-8f0b-cf72-'
+            '0378e413a31c/VHD-a7c0f37e-b7fb-4a44-a6fe-05067fb84c09.vhd', options)
+
+        self.assertEqual(1, self.mock_subprocess.Popen.call_count)
+        proc_args = ' '.join(self.mock_subprocess.Popen.call_args[0][0])
+        self.assertIn('/usr/sbin/tap-ctl open', proc_args)
+        self.assertIn('-e 4', proc_args)
+        self.assertIn('-s', proc_args)
+
+    def test_open_intellicache_parent(self):
+        """
+        TapCtl open, intellicache parent
+        """
+        mock_process = mock.MagicMock(autospec='subprocess.Popen')
+        mock_process.stdout = StringIO('')
+        mock_process.wait.return_value = 0
+        self.mock_subprocess.Popen.side_effect = [mock_process]
+
+        options = {
+            'rdonly': False,
+            'lcache': True,
+        }
+
+        blktap2.TapCtl.open(
+            22127, 2, 'vhd', '/dev/VG_XenStorage-2eeb9fd5-6545-8f0b-cf72-'
+            '0378e413a31c/VHD-a7c0f37e-b7fb-4a44-a6fe-05067fb84c09.vhd', options)
+
+        self.assertEqual(1, self.mock_subprocess.Popen.call_count)
+        proc_args = ' '.join(self.mock_subprocess.Popen.call_args[0][0])
+        self.assertIn('/usr/sbin/tap-ctl open', proc_args)
+        self.assertIn('-r', proc_args)
+
+    def test_open_cbt_log(self):
+        """
+        TapCtl open, CBT logging
+        """
+        mock_process = mock.MagicMock(autospec='subprocess.Popen')
+        mock_process.stdout = StringIO('')
+        mock_process.wait.return_value = 0
+        self.mock_subprocess.Popen.side_effect = [mock_process]
+
+        options = {
+            'cbtlog': ('/dev/VG_XenStorage-9bf5335b-7fef-298c-109c-'
+                       '1d12e931edfd/b76f0618-4dad-4b15-825f'
+                       '-b0b0fb006d67.cbtlog')
+        }
+
+        blktap2.TapCtl.open(
+            22127, 2, 'vhd', '/dev/VG_XenStorage-2eeb9fd5-6545-8f0b-cf72-'
+            '0378e413a31c/VHD-a7c0f37e-b7fb-4a44-a6fe-05067fb84c09.vhd', options)
+
+        self.assertEqual(1, self.mock_subprocess.Popen.call_count)
+        proc_args = ' '.join(self.mock_subprocess.Popen.call_args[0][0])
+        self.assertIn('/usr/sbin/tap-ctl open', proc_args)
+        self.assertIn('-C /dev/VG_XenStorage-9bf5335b-7fef-298c-109c-'
+                      '1d12e931edfd/b76f0618-4dad-4b15-825f'
+                      '-b0b0fb006d67.cbtlog',
+                      proc_args)
+
+    @mock.patch('blktap2.TapCtl._load_key')
+    def test_open_encryption(self, mock_load_key):
+        """
+        TapCtl open, with encryption key
+        """
+        mock_process = mock.MagicMock(autospec='subprocess.Popen')
+        mock_process.stdout = StringIO('')
+        mock_process.wait.return_value = 0
+        self.mock_subprocess.Popen.side_effect = [mock_process]
+
+        options = {'key_hash':
+                   '02ebc80e3322161efa5c6b3abe46acc'
+                   '0ba1703c469b6d84424e1768e86a652e0',
+                   'vdi_uuid': 'a7c0f37e-b7fb-4a44-a6fe-05067fb84c09'}
+
+        rand_data = bytearray(os.urandom(1000000))
+        mock_load_key.return_value = rand_data
+
+        blktap2.TapCtl.open(
+            22127, 2, 'vhd', '/dev/VG_XenStorage-2eeb9fd5-6545-8f0b-cf72-'
+            '0378e413a31c/VHD-a7c0f37e-b7fb-4a44-a6fe-05067fb84c09.vhd', options)
+
+        mock_load_key.assert_called_with(
+            '02ebc80e3322161efa5c6b3abe46acc'
+            '0ba1703c469b6d84424e1768e86a652e0',
+            'a7c0f37e-b7fb-4a44-a6fe-05067fb84c09')
+        self.assertEqual(1, self.mock_subprocess.Popen.call_count)
+        proc_args = ' '.join(self.mock_subprocess.Popen.call_args[0][0])
+        self.assertIn('/usr/sbin/tap-ctl open', proc_args)
+        self.assertIn('-p 22127', proc_args)
+        self.assertIn('-m 2', proc_args)
+        self.assertIn('-a vhd:/dev/VG_XenStorage-2eeb9fd5-6545-8f0b-cf72-'
+            '0378e413a31c/VHD-a7c0f37e-b7fb-4a44-a6fe-05067fb84c09.vhd',
+                      proc_args)
+        self.assertIn('-E', proc_args)
+
+    @mock.patch('blktap2.TapCtl._load_key')
+    def test_open_encryption_nokey(self, mock_load_key):
+        """
+        TapCtl open, with encryption no key found
+        """
+        options = {'key_hash':
+                   '02ebc80e3322161efa5c6b3abe46acc'
+                   '0ba1703c469b6d84424e1768e86a652e0',
+                   'vdi_uuid': 'a7c0f37e-b7fb-4a44-a6fe-05067fb84c09'}
+
+        mock_load_key.return_value = None
+
+        with self.assertRaises(util.SMException):
+            blktap2.TapCtl.open(
+                22127, 2, 'vhd', '/dev/VG_XenStorage-2eeb9fd5-6545-8f0b-cf72-'
+                '0378e413a31c/VHD-a7c0f37e-b7fb-4a44-a6fe-05067fb84c09.vhd', options)
+
+    def test_stats(self):
+        """
+        TapCtl stats
+        """
+        mock_process = mock.MagicMock(autospec='subprocess.Popen')
+        mock_process.stdout = StringIO('{ "name": "vhd:/dev/VG_XenStorage-2eeb9fd5-6545-8f0b-cf72-0378e413a31c/VHD-a7c0f37e-b7fb-4a44-a6fe-05067fb84c09", "secs": [ 688, 0 ], "images": [ { "name": "/dev/VG_XenStorage-2eeb9fd5-6545-8f0b-cf72-0378e413a31c/VHD-a7c0f37e-b7fb-4a44-a6fe-05067fb84c09", "hits": [ 688, 0 ], "fail": [ 0, 0 ], "driver": { "type": 4, "name": "vhd", "status": null } } ], "tap": { "minor": 0, "reqs": [ 35, 35 ], "kicks": [ 33, 28 ] }, "FIXME_enospc_redirect_count": 0, "nbd_mirror_failed": 0, "reqs_outstanding": 0, "read_caching": "false" }')
+        mock_process.wait.return_value = 0
+        self.mock_subprocess.Popen.side_effect = [mock_process]
+
+        results = blktap2.TapCtl.stats(705, 0)
+
+        self.assertIsNotNone(results)
+        results_dict = json.loads(results)
+        self.assertIn('name', results_dict)
+        self.assertIn('secs', results_dict)
+        self.assertIn('images', results_dict)
+        self.assertIn('hits', results_dict['images'][0])
+        self.assertIn('fail', results_dict['images'][0])
+
+    def test_major(self):
+        """
+        TapCtl major
+        """
+        mock_process = mock.MagicMock(autospec='subprocess.Popen')
+        mock_process.stdout = StringIO('254')
+        mock_process.wait.return_value = 0
+        self.mock_subprocess.Popen.side_effect = [mock_process]
+
+        results = blktap2.TapCtl.major()
+
+        self.assertEqual(254, results)