Move test stuff to tests

synapse/util/file_consumer.py

@@ -13,7 +13,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from twisted.internet import defer, threads, reactor
+from twisted.internet import threads, reactor
 
 from synapse.util.logcontext import make_deferred_yieldable
 
@@ -57,10 +57,6 @@ class BackgroundFileConsumer(object):
         # If the _writer thread throws an exception it gets stored here.
         self._write_exception = None
 
-        # A deferred that gets resolved when the bytes_queue gets empty.
-        # Mainly used for tests.
-        self._notify_empty_deferred = None
-
     def registerProducer(self, producer, streaming):
         """Part of IConsumer interface
 
@@ -113,9 +109,6 @@ class BackgroundFileConsumer(object):
                     if self._bytes_queue.qsize() <= self._RESUME_ON_QUEUE_SIZE:
                         reactor.callFromThread(self._resume_paused_producer)
 
-                if self._notify_empty_deferred and self._bytes_queue.empty():
-                    reactor.callFromThread(self._notify_empty)
-
                 bytes = self._bytes_queue.get()
 
                 # If we get a None (or empty list) then that's a signal used
@@ -144,20 +137,3 @@ class BackgroundFileConsumer(object):
         if self._paused_producer and self._producer:
             self._paused_producer = False
             self._producer.resumeProducing()
-
-    def _notify_empty(self):
-        """Called when the _writer thread thinks the queue may be empty and
-        we should notify anything waiting on `wait_for_writes`
-        """
-        if self._notify_empty_deferred and self._bytes_queue.empty():
-            d = self._notify_empty_deferred
-            self._notify_empty_deferred = None
-            d.callback(None)
-
-    def wait_for_writes(self):
-        """Wait for the write queue to be empty and for writes to have
-        finished. This is mainly useful for tests.
-        """
-        if not self._notify_empty_deferred:
-            self._notify_empty_deferred = defer.Deferred()
-        return self._notify_empty_deferred

tests/util/test_file_consumer.py

@@ -14,7 +14,7 @@
 # limitations under the License.
 
 
-from twisted.internet import defer
+from twisted.internet import defer, reactor
 from mock import NonCallableMock
 
 from synapse.util.file_consumer import BackgroundFileConsumer
@@ -53,7 +53,7 @@ class FileConsumerTests(unittest.TestCase):
 
     @defer.inlineCallbacks
     def test_push_consumer(self):
-        string_file = StringIO()
+        string_file = BlockingStringWrite()
         consumer = BackgroundFileConsumer(string_file)
 
         try:
@@ -62,14 +62,14 @@ class FileConsumerTests(unittest.TestCase):
             consumer.registerProducer(producer, True)
 
             consumer.write("Foo")
-            yield consumer.wait_for_writes()
+            yield string_file.wait_for_n_writes(1)
 
-            self.assertEqual(string_file.getvalue(), "Foo")
+            self.assertEqual(string_file.buffer, "Foo")
 
             consumer.write("Bar")
-            yield consumer.wait_for_writes()
+            yield string_file.wait_for_n_writes(2)
 
-            self.assertEqual(string_file.getvalue(), "FooBar")
+            self.assertEqual(string_file.buffer, "FooBar")
         finally:
             consumer.unregisterProducer()
 
@@ -85,15 +85,22 @@ class FileConsumerTests(unittest.TestCase):
         try:
             producer = NonCallableMock(spec_set=["pauseProducing", "resumeProducing"])
 
+            resume_deferred = defer.Deferred()
+            producer.resumeProducing.side_effect = lambda: resume_deferred.callback(None)
+
             consumer.registerProducer(producer, True)
 
+            number_writes = 0
             with string_file.write_lock:
                 for _ in range(consumer._PAUSE_ON_QUEUE_SIZE):
                     consumer.write("Foo")
+                    number_writes += 1
 
                 producer.pauseProducing.assert_called_once()
 
-            yield consumer.wait_for_writes()
+            yield string_file.wait_for_n_writes(number_writes)
+
+            yield resume_deferred
             producer.resumeProducing.assert_called_once()
         finally:
             consumer.unregisterProducer()
@@ -131,8 +138,39 @@ class BlockingStringWrite(object):
         self.closed = False
         self.write_lock = threading.Lock()
 
+        self._notify_write_deferred = None
+        self._number_of_writes = 0
+
     def write(self, bytes):
-        self.buffer += bytes
+        with self.write_lock:
+            self.buffer += bytes
+            self._number_of_writes += 1
+
+        reactor.callFromThread(self._notify_write)
 
     def close(self):
         self.closed = True
+
+    def _notify_write(self):
+        "Called by write to indicate a write happened"
+        with self.write_lock:
+            if not self._notify_write_deferred:
+                return
+            d = self._notify_write_deferred
+            self._notify_write_deferred = None
+        d.callback(None)
+
+    @defer.inlineCallbacks
+    def wait_for_n_writes(self, n):
+        "Wait for n writes to have happened"
+        while True:
+            with self.write_lock:
+                if n <= self._number_of_writes:
+                    return
+
+                if not self._notify_write_deferred:
+                    self._notify_write_deferred = defer.Deferred()
+
+                d = self._notify_write_deferred
+
+            yield d