diff --git a/chainsyncer/driver.py b/chainsyncer/driver.py
index 0dc9306..6f52c86 100644
--- a/chainsyncer/driver.py
+++ b/chainsyncer/driver.py
@@ -124,6 +124,7 @@ class SyncDriver:
 
 
     def process_single(self, conn, block, tx):
+        logg.debug('single')
         self.session.filter(conn, block, tx)
 
 
diff --git a/chainsyncer/unittest/base.py b/chainsyncer/unittest/base.py
index 2674d85..632228c 100644
--- a/chainsyncer/unittest/base.py
+++ b/chainsyncer/unittest/base.py
@@ -15,6 +15,10 @@ from chainsyncer.driver import SyncDriver
 logg = logging.getLogger().getChild(__name__)
 
 
+class MockFilterError(Exception):
+    pass
+
+
 class MockConn:
     """Noop connection mocker.
 
@@ -82,7 +86,7 @@ class MockStore(State):
 
 class MockFilter:
 
-    def __init__(self, name, brk=False, z=None):
+    def __init__(self, name, brk=None, brk_hard=None, z=None):
         self.name = name
         if z == None:
             h = hashlib.sha256()
@@ -90,6 +94,7 @@ class MockFilter:
             z = h.digest()
         self.z = z
         self.brk = brk
+        self.brk_hard = brk_hard
         self.contents = []
 
 
@@ -102,8 +107,21 @@ class MockFilter:
 
 
     def filter(self, conn, block, tx):
+        r = False
         self.contents.append((block.number, tx.index, tx.hash,))
-        return self.brk
+        if self.brk_hard != None:
+            r = True
+            if self.brk_hard > 0:
+                r = True
+            self.brk_hard -= 1
+            if r:
+                raise MockFilterError()
+        if self.brk != None:
+            if self.brk > 0:
+                r = True
+            self.brk -= 1
+        logg.debug('filter {} r {}'.format(self.common_name(), r))
+        return r
 
 
 class MockDriver(SyncDriver):
diff --git a/tests/test_session.py b/tests/test_session.py
index cfb91dd..0c57834 100644
--- a/tests/test_session.py
+++ b/tests/test_session.py
@@ -21,6 +21,7 @@ from chainsyncer.unittest import (
         MockTx,
         MockBlock,
         MockDriver,
+        MockFilterError,
         )
 from chainsyncer.driver import SyncDriver
 
@@ -81,5 +82,36 @@ class TestFilter(unittest.TestCase):
         self.assertEqual(len(fltr_one.contents), 3)
 
 
+    def test_driver_interrupt(self):
+        drv = MockDriver(self.store, target=1)
+
+        tx_hash = os.urandom(32).hex()
+        tx = MockTx(0, tx_hash)
+        block = MockBlock(0, [tx_hash])
+        drv.add_block(block)
+
+        fltr_one = MockFilter('foo', brk_hard=1)
+        self.store.register(fltr_one)
+        fltr_two = MockFilter('bar')
+        self.store.register(fltr_two)
+
+        with self.assertRaises(MockFilterError):
+            drv.run(self.conn)
+
+        store = SyncFsStore(self.path)
+        drv = MockDriver(store, target=1)
+        drv.add_block(block)
+
+        tx_hash_one = os.urandom(32).hex()
+        tx = MockTx(0, tx_hash_one)
+        tx_hash_two = os.urandom(32).hex()
+        tx = MockTx(1, tx_hash_two)
+        block = MockBlock(1, [tx_hash_one, tx_hash_two])
+        drv.add_block(block)
+
+        with self.assertRaises(SyncDone):
+            drv.run(self.conn)
+
+
 if __name__ == '__main__':
     unittest.main()