diff --git a/chainsyncer/driver.py b/chainsyncer/driver.py
index 119f0d4..7718032 100644
--- a/chainsyncer/driver.py
+++ b/chainsyncer/driver.py
@@ -55,7 +55,7 @@ class SyncDriver:
         self.running = False
 
 
-    def run(self, conn):
+    def run(self, conn, interval=1):
         while self.running_global:
             self.session = SyncSession(self.store)
             item = self.session.start()
@@ -63,7 +63,7 @@ class SyncDriver:
                 self.running = False
                 self.running_global = False
                 break
-            self.loop(conn, item)
+            self.loop(conn, item, interval=interval)
 
 
     def idle(self, interval):
@@ -92,7 +92,7 @@ class SyncDriver:
         time.sleep(interval)
 
 
-    def loop(self, conn, item):
+    def loop(self, conn, item, interval=1):
         logg.debug('started loop')
         tx_start = item.tx_cursor
         while self.running and SyncDriver.running_global:
@@ -115,7 +115,6 @@ class SyncDriver:
                     self.process(conn, item, block, tx_start)
                 except IndexError:
                     item.next(advance_block=True)
-                logg.debug('foo')
                 tx_start = 0
                 time.sleep(self.yield_delay)
             if self.post_callback != None:
diff --git a/chainsyncer/unittest/base.py b/chainsyncer/unittest/base.py
index f33a43b..420c7fd 100644
--- a/chainsyncer/unittest/base.py
+++ b/chainsyncer/unittest/base.py
@@ -17,11 +17,17 @@ logg = logging.getLogger().getChild(__name__)
 
 
 def state_event_handler(k, v_old, v_new):
-    logg.log(logging.STATETRACE, 'sync state change key {}: {} -> {}'.format(k, v_old, v_new))
+    if v_old == None:
+        logg.log(logging.STATETRACE, 'sync state create key {}: -> {}'.format(k, v_new))
+    else:
+        logg.log(logging.STATETRACE, 'sync state change key {}: {} -> {}'.format(k, v_old, v_new))
     
 
 def filter_state_event_handler(k, v_old, v_new):
-    logg.log(logging.STATETRACE, 'filter state change key {}: {} -> {}'.format(k, v_old, v_new))
+    if v_old == None:
+        logg.log(logging.STATETRACE, 'filter state create key {}: -> {}'.format(k, v_new))
+    else:
+        logg.log(logging.STATETRACE, 'filter state change key {}: {} -> {}'.format(k, v_old, v_new))
 
 
 class MockFilterError(Exception):
@@ -45,9 +51,21 @@ class MockBlockGenerator:
                 txs.append(tx)
 
             block = MockBlock(self.cursor, txs)
-            driver.add_block(block)
+            self.blocks[self.cursor] = block
             self.cursor += 1
 
+        if driver != None:
+            self.apply(driver)
+
+
+    def apply(self, driver, offset=0):
+        block_numbers = list(self.blocks.keys())
+        for block_number in block_numbers:
+            if block_number < offset:
+                continue
+            block = self.blocks[block_number]
+            driver.add_block(block) 
+
 
 class MockConn:
     """Noop connection mocker.
@@ -151,15 +169,24 @@ class MockFilter:
             if self.brk > 0:
                 r = True
             self.brk -= 1
-        logg.debug('filter {} r {} block {}'.format(self.common_name(), r, block.number))
+        logg.debug('filter {} result {} block {}'.format(self.common_name(), r, block.number))
         return r
 
 
 class MockDriver(SyncDriver):
 
-    def __init__(self, store, offset=0, target=-1):
+    def __init__(self, store, offset=0, target=-1, interrupt_block=None, interrupt_tx=None, interrupt_global=False):
         super(MockDriver, self).__init__(store, offset=offset, target=target)
         self.blocks = {}
+        self.interrupt = None
+        if interrupt_block != None:
+            interrupt_block = int(interrupt_block)
+            if interrupt_tx == None:
+                interrupt_tx = 0
+            else:
+                interrupt_tx = int(interrupt_tx)
+            self.interrupt = (interrupt_block, interrupt_tx,)
+        self.interrupt_global = interrupt_global
 
 
     def add_block(self, block):
@@ -173,7 +200,14 @@ class MockDriver(SyncDriver):
 
     def process(self, conn, item, block, tx_start):
         i = tx_start
-        while True:
+        while self.running:
+            if self.interrupt != None:
+                if self.interrupt[0] == block.number and self.interrupt[1] == i:
+                    logg.info('interrupt triggered at {}'.format(self.interrupt))
+                    if self.interrupt_global:
+                        SyncDriver.running_global = False
+                    self.running = False
+                    break
             tx = block.tx(i)
             self.process_single(conn, block, tx)
             item.next()
diff --git a/tests/test_session.py b/tests/test_session.py
index 7823e36..0d2699f 100644
--- a/tests/test_session.py
+++ b/tests/test_session.py
@@ -117,9 +117,20 @@ class TestFilter(unittest.TestCase):
 
 
     def test_driver_interrupt_sync(self):
+        drv = MockDriver(self.store, interrupt_block=1)
         generator = MockBlockGenerator()
-        drv = MockDriver(self.store, target=1)
-        generator.generate([1, 2], driver=drv)
+        generator.generate([3, 1, 2], driver=drv)
+
+        fltr_one = MockFilter('foo')
+        self.store.register(fltr_one)
+
+        drv.run(self.conn, interval=0.1)
+
+
+        store = SyncFsStore(self.path, state_event_callback=state_event_handler, filter_state_event_callback=filter_state_event_handler)
+        drv = MockDriver(store)
+        generator.apply(drv, offset=1)
+        drv.run(self.conn, interval=0.1)
 
 
 if __name__ == '__main__':