Add batcher test cases

tests/test_batcher.py

@@ -0,0 +1,107 @@
+# -*- coding: utf-8 -*-
+
+"""Batcher test cases."""
+
+from unittest import TestCase
+
+from mock import (
+    MagicMock as Mock,
+    patch,
+)
+from six.moves import range
+
+from rabbithole.batcher import Batcher
+
+
+class TestBatcher(TestCase):
+
+    """Batcher test cases."""
+
+    def test_first_message_received(self):
+        """Message appended to batch and timer started."""
+        exchange = 'exchange'
+        payload = 'payload'
+
+        batcher = Batcher()
+        batcher.batch_ready = Mock()
+        with patch('rabbithole.batcher.threading') as threading:
+            batcher.message_received_cb('sender', exchange, payload)
+            threading.Timer.assert_called_once_with(
+                batcher.TIME_LIMIT,
+                batcher.time_expired_cb,
+                (exchange, ),
+            )
+        self.assertListEqual(batcher.batches[exchange], [payload])
+
+    def test_size_limit_exceeded(self):
+        """Batch queued when size limit is exceed."""
+        exchange = 'exchange'
+        payload = 'payload'
+
+        batcher = Batcher()
+        batcher.batch_ready = Mock()
+        with patch('rabbithole.batcher.threading'):
+            for _ in range(batcher.SIZE_LIMIT):
+                batcher.message_received_cb('sender', exchange, payload)
+
+        batcher.batch_ready.send.assert_called_with(
+            batcher,
+            exchange_name=exchange,
+            batch=[payload] * batcher.SIZE_LIMIT,
+        )
+        self.assertListEqual(batcher.batches[exchange], [])
+
+    def test_time_limit_exceeded(self):
+        """Batch queued whem time limit is exceeded."""
+        exchange = 'exchange'
+        payload = 'payload'
+
+        batcher = Batcher()
+        batcher.batch_ready = Mock()
+        with patch('rabbithole.batcher.threading'):
+            batcher.message_received_cb('sender', exchange, payload)
+        batcher.time_expired_cb(exchange)
+
+        batcher.batch_ready.send.assert_called_with(
+            batcher,
+            exchange_name=exchange,
+            batch=[payload],
+        )
+        self.assertListEqual(batcher.batches[exchange], [])
+
+    def test_expired_timer_not_found(self):
+        """Warning written to logs when expired timer is not found."""
+        exchange = 'exchange'
+
+        batcher = Batcher()
+        with patch('rabbithole.batcher.LOGGER') as logger:
+            batcher.time_expired_cb(exchange)
+            logger.warning.assert_called_with(
+                'Timer not found for: %r',
+                exchange,
+            )
+
+    def test_timer_already_active(self):
+        """Warning written to logs when timer is alreadya active."""
+        exchange = 'exchange'
+
+        batcher = Batcher()
+        batcher.timers[exchange] = Mock()
+        with patch('rabbithole.batcher.LOGGER') as logger:
+            batcher.start_timer(exchange)
+            logger.warning.assert_called_with(
+                'Timer already active for: %r',
+                exchange,
+            )
+
+    def test_cancelled_timer_not_found(self):
+        """Warning written to logs when cancelled timer is not found."""
+        exchange = 'exchange'
+
+        batcher = Batcher()
+        with patch('rabbithole.batcher.LOGGER') as logger:
+            batcher.cancel_timer(exchange)
+            logger.warning.assert_called_with(
+                'Timer not found for: %r',
+                exchange,
+            )