diff --git a/drivers/BaseISCSI.py b/drivers/BaseISCSI.py
index 0b72e9293..99890b4e8 100755
--- a/drivers/BaseISCSI.py
+++ b/drivers/BaseISCSI.py
@@ -416,10 +416,14 @@ def attach(self, sr_uuid):
         if 'SCSIid' in self.dconf:
             if self.mpath == 'true':
                 self.mpathmodule.refresh(self.dconf['SCSIid'], 0)
-            devs = os.listdir("/dev/disk/by-scsid/%s" % self.dconf['SCSIid'])
+            dev_path = os.path.join("/dev/disk/by-scsid", self.dconf['SCSIid'])
+            if not os.path.exists(dev_path):
+                raise xs_errors.XenError('ConfigSCSIid')
+
+            devs = os.listdir(dev_path)
             for dev in devs:
-                realdev = os.path.realpath("/dev/disk/by-scsid/%s/%s" % (self.dconf['SCSIid'], dev))
-                util.set_scheduler(realdev.split("/")[-1])
+                realdev = os.path.realpath(os.path.join(dev_path, dev))
+                util.set_scheduler(os.path.basename(realdev))
 
     def detach(self, sr_uuid, delete=False):
         keys = []
diff --git a/tests/test_BaseISCSI.py b/tests/test_BaseISCSI.py
new file mode 100644
index 000000000..31f1f5832
--- /dev/null
+++ b/tests/test_BaseISCSI.py
@@ -0,0 +1,108 @@
+"""
+Unit tests for the Base ISCSI SR
+"""
+
+from unittest import mock
+import unittest
+from uuid import uuid4
+
+from BaseISCSI import BaseISCSISR
+import SR
+import SRCommand
+from util import CommandException
+
+
+class TestBaseISCSI(unittest.TestCase):
+
+    def setUp(self):
+        self.addCleanup(mock.patch.stopall)
+
+        util_patcher = mock.patch('BaseISCSI.util', autospec=True)
+        self.mock_util = util_patcher.start()
+        self.mock_util.CommandException = CommandException
+
+        self.mock_session = mock.MagicMock()
+        xenapi_patcher = mock.patch('SR.XenAPI')
+        mock_xenapi = xenapi_patcher.start()
+        mock_xenapi.xapi_local.return_value = self.mock_session
+
+        iscsilib_patcher = mock.patch('BaseISCSI.iscsilib', autospec=True)
+        self.mock_iscsilib = iscsilib_patcher.start()
+
+        copy_patcher = mock.patch('LVHDoISCSISR.SR.copy.deepcopy')
+        self.mock_copy = copy_patcher.start()
+
+        def deepcopy(to_copy):
+            return to_copy
+
+        self.mock_copy.side_effect = deepcopy
+
+        dummy_cmd = mock.create_autospec(SRCommand)
+        dummy_cmd.dconf = {
+            'SCSIid': '3600a098038313577792450384a4a6275',
+            'target': "10.70.89.34",
+            'targetIQN': 'iqn.2009-01.example.test:iscsi085e938a'
+        }
+        dummy_cmd.params = {
+            'command': 'nop',
+            'session_ref': 'test_session',
+            'host_ref': 'test_host',
+            'sr_ref': 'sr_ref'
+        }
+        dummy_cmd.cmd = None
+
+        self.sr_uuid = str(uuid4())
+
+        self.subject = BaseISCSISR(
+            dummy_cmd, self.sr_uuid
+        )
+
+    def setup_path_mocks(self):
+        self.path_contents = {}
+        exists_patcher = mock.patch('BaseISCSI.os.path.exists', autospec=True)
+        self.mock_exists = exists_patcher.start()
+        self.mock_exists.side_effect = self.exists
+        listdir_patcher = mock.patch('BaseISCSI.os.listdir', autospec=True)
+        mock_listdir = listdir_patcher.start()
+        mock_listdir.side_effect = self.listdir
+
+    def exists(self, path):
+        print(f'checking existance of {path}')
+        return path in self.path_contents
+
+    def listdir(self, path):
+        return self.path_contents[path]
+
+    @mock.patch('BaseISCSI.BaseISCSISR._initPaths', autospec=True)
+    def test_attach_tgt_present_path_found(self, mock_init_paths):
+        # Arrange
+        self.setup_path_mocks()
+        self.path_contents.update(
+            {'/dev/disk/by-scsid/3600a098038313577792450384a4a6275': ['sdb']})
+        self.mock_util._testHost.return_value = None
+        self.mock_util.sessions_less_than_targets.return_value = False
+        self.mock_iscsilib._checkTGT.return_value = True
+        self.mock_iscsilib.parse_IP_port.side_effect = [
+            ('tgt1', '3260')
+            ]
+
+        # Act
+        self.subject.attach(self.sr_uuid)
+
+    @mock.patch('BaseISCSI.BaseISCSISR._initPaths', autospec=True)
+    @mock.patch('BaseISCSI.xs_errors.XML_DEFS', "drivers/XE_SR_ERRORCODES.xml")
+    def test_attach_tgt_present_path_not_found(self, mock_init_paths):
+        # Arrange
+        self.mock_util._testHost.return_value = None
+        self.mock_util.sessions_less_than_targets.return_value = False
+        self.mock_iscsilib._checkTGT.return_value = True
+        self.mock_iscsilib.parse_IP_port.side_effect = [
+            ('tgt1', '3260')
+            ]
+
+        # Act
+        with self.assertRaises(SR.SROSError) as srose:
+            self.subject.attach(self.sr_uuid)
+
+        # Assert
+        self.assertEqual(107, srose.exception.errno)