Fix QueueFile to support read-to-end semantics and add some tests

test/test_queuefile.py

@@ -0,0 +1,79 @@
+import unittest
+
+from StringIO import StringIO
+
+from util.registry.queueprocess import QueueResult
+from util.registry.queuefile import QueueFile
+
+class FakeQueue(object):
+  def __init__(self):
+    self.items = []
+
+  def get(self, block):
+    return self.items.pop(0)
+
+  def put(self, data):
+    self.items.append(data)
+
+
+class TestQueueFile(unittest.TestCase):
+  def test_basic(self):
+    queue = FakeQueue()
+    queue.put(QueueResult('hello world', None))
+    queue.put(QueueResult('! how goes there?', None))
+    queue.put(QueueResult(None, None))
+
+    queuefile = QueueFile(queue)
+    self.assertEquals(queuefile.read(), 'hello world! how goes there?')
+
+  def test_chunk_reading(self):
+    queue = FakeQueue()
+    queue.put(QueueResult('hello world', None))
+    queue.put(QueueResult('! how goes there?', None))
+    queue.put(QueueResult(None, None))
+
+    queuefile = QueueFile(queue)
+    data = ''
+
+    while True:
+      result = queuefile.read(size=2)
+      if not result:
+        break
+
+      data += result
+
+    self.assertEquals(data, 'hello world! how goes there?')
+
+  def test_unhandled_exception(self):
+    queue = FakeQueue()
+    queue.put(QueueResult('hello world', None))
+    queue.put(QueueResult(None, IOError('some exception')))
+    queue.put(QueueResult('! how goes there?', None))
+    queue.put(QueueResult(None, None))
+
+    queuefile = QueueFile(queue)
+
+    with self.assertRaises(IOError):
+      queuefile.read(size=12)
+
+  def test_handled_exception(self):
+    queue = FakeQueue()
+    queue.put(QueueResult('hello world', None))
+    queue.put(QueueResult(None, IOError('some exception')))
+    queue.put(QueueResult('! how goes there?', None))
+    queue.put(QueueResult(None, None))
+
+    ex_found = [None]
+
+    def handler(ex):
+      ex_found[0] = ex
+
+    queuefile = QueueFile(queue)
+    queuefile.add_exception_handler(handler)
+    queuefile.read(size=12)
+
+    self.assertIsNotNone(ex_found[0])
+
+
+if __name__ == '__main__':
+  unittest.main()