diff --git a/devsupApp/src/Makefile b/devsupApp/src/Makefile
index 2d01d17..3a26547 100644
--- a/devsupApp/src/Makefile
+++ b/devsupApp/src/Makefile
@@ -40,6 +40,7 @@ PY += devsup/disect.py
 PY += devsup/ptable.py
 
 PY += devsup/test/__init__.py
+PY += devsup/test/util.py
 PY += devsup/test/test_db.py
 
 #===========================
diff --git a/devsupApp/src/devsup/test/test_db.py b/devsupApp/src/devsup/test/test_db.py
index 0ab6247..2dc33e0 100644
--- a/devsupApp/src/devsup/test/test_db.py
+++ b/devsupApp/src/devsup/test/test_db.py
@@ -10,43 +10,10 @@ from ..db import getRecord
 from .. import _dbapi
 from .. import _init
 
-# short-circuit warning from _dbapi._init()
-os.environ['TOP'] = _dbapi.XPYDEV_BASE
+from .util import IOCHelper
 
-class IOCHelper(unittest.TestCase):
-    db = None
-    autostart = running = False
-    def setUp(self):
-        print("testdbPrepare()")
-        _dbapi._UTest.testdbPrepare()
-        _init(iocMain=False) # load base.dbd
-
-        if self.db is not None:
-            with tempfile.NamedTemporaryFile() as F:
-                F.write(self.db.encode('ascii'))
-                F.flush()
-                _dbapi.dbReadDatabase(F.name)
-
-        if self.autostart:
-            self.iocInit()
-
-    def tearDown(self):
-        self.iocShutdown();
-        print("testdbCleanup()")
-        _dbapi.initHookAnnounce(9999) # our magic/fake AtExit hook
-        _dbapi._UTest.testdbCleanup()
-
-    def iocInit(self):
-        if not self.running:
-            print("testIocInitOk")
-            _dbapi._UTest.testIocInitOk()
-            self.running = True
-
-    def iocShutdown(self):
-        if self.running:
-            print("testIocShutdownOk")
-            _dbapi._UTest.testIocShutdownOk()
-            self.running = False
+# short-circuit warning from base_registerRecordDeviceDriver()
+os.environ['TOP'] = _dbapi.XPYDEV_BASE # external code use devsup.XPYDEV_BASE
 
 class TestScan(IOCHelper):
     db = """
@@ -90,7 +57,6 @@ class TestField(IOCHelper):
             field(NELM, "10")
         }
     """
-    autostart = True
 
     def test_ai(self):
         rec = getRecord("rec:ai")
@@ -171,7 +137,6 @@ class TestDset(IOCHelper):
             field(INP , "@devsup.test.test_db|TestDset foo bar")
         }
     """
-    autostart = True
 
     class Increment(object):
         def process(self, rec, reason):
diff --git a/devsupApp/src/devsup/test/util.py b/devsupApp/src/devsup/test/util.py
new file mode 100644
index 0000000..6177a4b
--- /dev/null
+++ b/devsupApp/src/devsup/test/util.py
@@ -0,0 +1,74 @@
+
+import os
+import unittest
+import tempfile
+
+import numpy
+from numpy.testing import assert_array_almost_equal, assert_array_equal
+
+from ..db import getRecord
+from .. import _dbapi
+from .. import _init
+
+__all__ = (
+    'IOCHelper',
+)
+
+class IOCHelper(unittest.TestCase):
+    """Test case run in an IOC. ::
+
+        from devsup.db import getRecord
+        from devsup.test.util impmort IOCHelper
+        class TestScan(IOCHelper): # sub-class of unittest.TestCase
+            db = \"\"\"
+                record(longout, foo) {}
+            \"\"\"
+            autostart = True
+
+            def test_link(self):
+                rec = getRecord('foo')
+                with rec: # dbScanLock()
+                    self.assertEqual(rec.VAL, 0)
+    """
+    # DB definition to be used.  May include eg. 'record(ai, "blah") {}'
+    db = None
+    # Whether to automatically run iocInit() before test methods
+    # whether iocInit() has been called
+    autostart = True
+    running = False
+
+    def setUp(self):
+        print("testdbPrepare()")
+        _dbapi._UTest.testdbPrepare()
+        _init(iocMain=False) # load base.dbd
+
+        if self.db is not None:
+            with tempfile.NamedTemporaryFile() as F:
+                F.write(self.db.encode('ascii'))
+                F.flush()
+                _dbapi.dbReadDatabase(F.name)
+
+        if self.autostart:
+            self.iocInit()
+
+    def tearDown(self):
+        self.iocShutdown();
+        print("testdbCleanup()")
+        _dbapi.initHookAnnounce(9999) # our magic/fake AtExit hook
+        _dbapi._UTest.testdbCleanup()
+
+    def iocInit(self):
+        """If not autostart, then this must be called before runtime database access is possible
+        """
+        if not self.running:
+            print("testIocInitOk")
+            _dbapi._UTest.testIocInitOk()
+            self.running = True
+
+    def iocShutdown(self):
+        """Call to stop IOC scanning processes.  Happens automatically during test tearDown
+        """
+        if self.running:
+            print("testIocShutdownOk")
+            _dbapi._UTest.testIocShutdownOk()
+            self.running = False