Merge pull request #88 from rdiomar/rdiomar_changes

Various changes/fixes, including:
* Allow customizing socket timeouts
* Read the correct number of bytes from kafka
* Guarantee reading the expected number of bytes from the socket every time
* Remove bufsize from client and conn
* SimpleConsumer flow changes
* Fix some error handling
* Add optional upper limit to consumer fetch buffer size
* Add and fix unit and integration tests

8 files changed, 613 insertions, 379 deletions

diff --git a/kafka/client.py b/kafka/client.py
index 71ededa..33c6d77 100644
--- a/kafka/client.py
+++ b/kafka/client.py
@@ -3,11 +3,12 @@ from collections import defaultdict
 from functools import partial
 from itertools import count
 import logging
-import socket
 import time
 
-from kafka.common import ErrorMapping, TopicAndPartition
-from kafka.common import ConnectionError, FailedPayloadsException
+from kafka.common import (
+    ErrorMapping, TopicAndPartition, ConnectionError,
+    FailedPayloadsException
+)
 from kafka.conn import KafkaConnection
 from kafka.protocol import KafkaProtocol
 
@@ -19,12 +20,12 @@ class KafkaClient(object):
     CLIENT_ID = "kafka-python"
     ID_GEN = count()
 
-    def __init__(self, host, port, bufsize=4096, client_id=CLIENT_ID):
+    def __init__(self, host, port, client_id=CLIENT_ID, timeout=10):
         # We need one connection to bootstrap
-        self.bufsize = bufsize
         self.client_id = client_id
+        self.timeout = timeout
         self.conns = {               # (host, port) -> KafkaConnection
-            (host, port): KafkaConnection(host, port, bufsize)
+            (host, port): KafkaConnection(host, port, timeout=timeout)
         }
         self.brokers = {}            # broker_id -> BrokerMetadata
         self.topics_to_brokers = {}  # topic_id -> broker_id
@@ -41,7 +42,7 @@ class KafkaClient(object):
         """
         if (broker.host, broker.port) not in self.conns:
             self.conns[(broker.host, broker.port)] = \
-                KafkaConnection(broker.host, broker.port, self.bufsize)
+                KafkaConnection(broker.host, broker.port, timeout=self.timeout)
 
         return self.conns[(broker.host, broker.port)]
 
@@ -165,14 +166,24 @@ class KafkaClient(object):
             request = encoder_fn(client_id=self.client_id,
                                  correlation_id=requestId, payloads=payloads)
 
+            failed = False
             # Send the request, recv the response
             try:
                 conn.send(requestId, request)
                 if decoder_fn is None:
                     continue
-                response = conn.recv(requestId)
-            except ConnectionError, e:  # ignore BufferUnderflow for now
-                log.warning("Could not send request [%s] to server %s: %s" % (request, conn, e))
+                try:
+                    response = conn.recv(requestId)
+                except ConnectionError, e:
+                    log.warning("Could not receive response to request [%s] "
+                                "from server %s: %s", request, conn, e)
+                    failed = True
+            except ConnectionError, e:
+                log.warning("Could not send request [%s] to server %s: %s",
+                            request, conn, e)
+                failed = True
+
+            if failed:
                 failed_payloads += payloads
                 self.topics_to_brokers = {} # reset metadata
                 continue
diff --git a/kafka/conn.py b/kafka/conn.py
index 1a3e260..c80f428 100644
--- a/kafka/conn.py
+++ b/kafka/conn.py
@@ -4,7 +4,6 @@ import socket
 import struct
 from threading import local
 
-from kafka.common import BufferUnderflowError
 from kafka.common import ConnectionError
 
 log = logging.getLogger("kafka")
@@ -19,14 +18,14 @@ class KafkaConnection(local):
     we can do something in here to facilitate multiplexed requests/responses
     since the Kafka API includes a correlation id.
     """
-    def __init__(self, host, port, bufsize=4096):
+    def __init__(self, host, port, timeout=10):
         super(KafkaConnection, self).__init__()
         self.host = host
         self.port = port
-        self.bufsize = bufsize
         self._sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
         self._sock.connect((host, port))
-        self._sock.settimeout(10)
+        self.timeout = timeout
+        self._sock.settimeout(self.timeout)
         self._dirty = False
 
     def __str__(self):
@@ -36,44 +35,31 @@ class KafkaConnection(local):
     #   Private API   #
     ###################
 
-    def _consume_response(self):
-        """
-        Fully consume the response iterator
-        """
-        return "".join(self._consume_response_iter())
-
-    def _consume_response_iter(self):
-        """
-        This method handles the response header and error messages. It
-        then returns an iterator for the chunks of the response
-        """
-        log.debug("Handling response from Kafka")
-
-        # Read the size off of the header
-        resp = self._sock.recv(4)
-        if resp == "":
-            self._raise_connection_error()
-        (size,) = struct.unpack('>i', resp)
-
-        messagesize = size - 4
-        log.debug("About to read %d bytes from Kafka", messagesize)
-
-        # Read the remainder of the response
-        total = 0
-        while total < messagesize:
-            resp = self._sock.recv(self.bufsize)
-            log.debug("Read %d bytes from Kafka", len(resp))
-            if resp == "":
-                raise BufferUnderflowError(
-                    "Not enough data to read this response")
-
-            total += len(resp)
-            yield resp
-
     def _raise_connection_error(self):
         self._dirty = True
         raise ConnectionError("Kafka @ {}:{} went away".format(self.host, self.port))
 
+    def _read_bytes(self, num_bytes):
+        bytes_left = num_bytes
+        resp = ''
+        log.debug("About to read %d bytes from Kafka", num_bytes)
+        if self._dirty:
+            self.reinit()
+        while bytes_left:
+            try:
+                data = self._sock.recv(bytes_left)
+            except socket.error:
+                log.exception('Unable to receive data from Kafka')
+                self._raise_connection_error()
+            if data == '':
+                log.error("Not enough data to read this response")
+                self._raise_connection_error()
+            bytes_left -= len(data)
+            log.debug("Read %d/%d bytes from Kafka", num_bytes - bytes_left, num_bytes)
+            resp += data
+
+        return resp
+
     ##################
     #   Public API   #
     ##################
@@ -89,7 +75,7 @@ class KafkaConnection(local):
             sent = self._sock.sendall(payload)
             if sent is not None:
                 self._raise_connection_error()
-        except socket.error:
+        except socket.error, e:
             log.exception('Unable to send payload to Kafka')
             self._raise_connection_error()
 
@@ -98,8 +84,14 @@ class KafkaConnection(local):
         Get a response from Kafka
         """
         log.debug("Reading response %d from Kafka" % request_id)
-        self.data = self._consume_response()
-        return self.data
+        # Read the size off of the header
+        resp = self._read_bytes(4)
+
+        (size,) = struct.unpack('>i', resp)
+
+        # Read the remainder of the response
+        resp = self._read_bytes(size)
+        return str(resp)
 
     def copy(self):
         """
@@ -124,5 +116,5 @@ class KafkaConnection(local):
         self.close()
         self._sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
         self._sock.connect((self.host, self.port))
-        self._sock.settimeout(10)
+        self._sock.settimeout(self.timeout)
         self._dirty = False
diff --git a/kafka/consumer.py b/kafka/consumer.py
index 226700e..eba2912 100644
--- a/kafka/consumer.py
+++ b/kafka/consumer.py
@@ -5,8 +5,8 @@ from itertools import izip_longest, repeat
 import logging
 import time
 from threading import Lock
-from multiprocessing import Process, Queue, Event, Value
-from Queue import Empty
+from multiprocessing import Process, Queue as MPQueue, Event, Value
+from Queue import Empty, Queue
 
 from kafka.common import (
     ErrorMapping, FetchRequest,
@@ -24,6 +24,11 @@ AUTO_COMMIT_INTERVAL = 5000
 FETCH_DEFAULT_BLOCK_TIMEOUT = 1
 FETCH_MAX_WAIT_TIME = 100
 FETCH_MIN_BYTES = 4096
+FETCH_BUFFER_SIZE_BYTES = 4096
+MAX_FETCH_BUFFER_SIZE_BYTES = FETCH_BUFFER_SIZE_BYTES * 8
+
+ITER_TIMEOUT_SECONDS = 60
+NO_MESSAGES_WAIT_TIME_SECONDS = 0.1
 
 
 class FetchContext(object):
@@ -34,13 +39,15 @@ class FetchContext(object):
         self.consumer = consumer
         self.block = block
 
-        if block and not timeout:
-            timeout = FETCH_DEFAULT_BLOCK_TIMEOUT
-
-        self.timeout = timeout * 1000
+        if block:
+            if not timeout:
+                timeout = FETCH_DEFAULT_BLOCK_TIMEOUT
+            self.timeout = timeout * 1000
 
     def __enter__(self):
         """Set fetch values based on blocking status"""
+        self.orig_fetch_max_wait_time = self.consumer.fetch_max_wait_time
+        self.orig_fetch_min_bytes = self.consumer.fetch_min_bytes
         if self.block:
             self.consumer.fetch_max_wait_time = self.timeout
             self.consumer.fetch_min_bytes = 1
@@ -48,9 +55,9 @@ class FetchContext(object):
             self.consumer.fetch_min_bytes = 0
 
     def __exit__(self, type, value, traceback):
-        """Reset values to default"""
-        self.consumer.fetch_max_wait_time = FETCH_MAX_WAIT_TIME
-        self.consumer.fetch_min_bytes = FETCH_MIN_BYTES
+        """Reset values"""
+        self.consumer.fetch_max_wait_time = self.orig_fetch_max_wait_time
+        self.consumer.fetch_min_bytes = self.orig_fetch_min_bytes
 
 
 class Consumer(object):
@@ -206,8 +213,14 @@ class SimpleConsumer(Consumer):
                          before a commit
     auto_commit_every_t: default 5000. How much time (in milliseconds) to
                          wait before commit
-
     fetch_size_bytes:    number of bytes to request in a FetchRequest
+    buffer_size:         default 4K. Initial number of bytes to tell kafka we
+                         have available. This will double as needed.
+    max_buffer_size:     default 16K. Max number of bytes to tell kafka we have
+                         available. None means no limit.
+    iter_timeout:        default None. How much time (in seconds) to wait for a
+                         message in the iterator before exiting. None means no
+                         timeout, so it will wait forever.
 
     Auto commit details:
     If both auto_commit_every_n and auto_commit_every_t are set, they will
@@ -218,12 +231,23 @@ class SimpleConsumer(Consumer):
     def __init__(self, client, group, topic, auto_commit=True, partitions=None,
                  auto_commit_every_n=AUTO_COMMIT_MSG_COUNT,
                  auto_commit_every_t=AUTO_COMMIT_INTERVAL,
-                 fetch_size_bytes=FETCH_MIN_BYTES):
-
+                 fetch_size_bytes=FETCH_MIN_BYTES,
+                 buffer_size=FETCH_BUFFER_SIZE_BYTES,
+                 max_buffer_size=MAX_FETCH_BUFFER_SIZE_BYTES,
+                 iter_timeout=None):
+
+        if max_buffer_size is not None and buffer_size > max_buffer_size:
+            raise ValueError("buffer_size (%d) is greater than "
+                             "max_buffer_size (%d)" %
+                             (buffer_size, max_buffer_size))
+        self.buffer_size = buffer_size
+        self.max_buffer_size = max_buffer_size
         self.partition_info = False     # Do not return partition info in msgs
         self.fetch_max_wait_time = FETCH_MAX_WAIT_TIME
         self.fetch_min_bytes = fetch_size_bytes
         self.fetch_started = defaultdict(bool)  # defaults to false
+        self.iter_timeout = iter_timeout
+        self.queue = Queue()
 
         super(SimpleConsumer, self).__init__(
             client, group, topic,
@@ -267,12 +291,6 @@ class SimpleConsumer(Consumer):
                     reqs.append(OffsetRequest(self.topic, partition, -2, 1))
                 elif whence == 2:
                     reqs.append(OffsetRequest(self.topic, partition, -1, 1))
-
-                    # The API returns back the next available offset
-                    # For eg: if the current offset is 18, the API will return
-                    # back 19. So, if we have to seek 5 points before, we will
-                    # end up going back to 14, instead of 13. Adjust this
-                    deltas[partition] -= 1
                 else:
                     pass
 
@@ -289,123 +307,111 @@ class SimpleConsumer(Consumer):
 
         count: Indicates the maximum number of messages to be fetched
         block: If True, the API will block till some messages are fetched.
-        timeout: If None, and block=True, the API will block infinitely.
-                 If >0, API will block for specified time (in seconds)
+        timeout: If block is True, the function will block for the specified
+                 time (in seconds) until count messages is fetched. If None,
+                 it will block forever.
         """
         messages = []
-        iterator = self.__iter__()
-
-        # HACK: This splits the timeout between available partitions
         if timeout:
-            timeout = timeout * 1.0 / len(self.offsets)
+            max_time = time.time() + timeout
 
-        with FetchContext(self, block, timeout):
-            while count > 0:
-                try:
-                    messages.append(next(iterator))
-                except StopIteration:
-                    break
+        while count > 0 and (timeout is None or timeout > 0):
+            message = self.get_message(block, timeout)
+            if message:
+                messages.append(message)
                 count -= 1
+            else:
+                # Ran out of messages for the last request.
+                if not block:
+                    # If we're not blocking, break.
+                    break
+                if timeout:
+                    # If we're blocking and have a timeout, reduce it to the
+                    # appropriate value
+                    timeout = max_time - time.time()
 
         return messages
 
-    def __iter__(self):
-        """
-        Create an iterate per partition. Iterate through them calling next()
-        until they are all exhausted.
-        """
-        iters = {}
-        for partition, offset in self.offsets.items():
-            iters[partition] = self.__iter_partition__(partition, offset)
+    def get_message(self, block=True, timeout=0.1):
+        if self.queue.empty():
+            # We're out of messages, go grab some more.
+            with FetchContext(self, block, timeout):
+                self._fetch()
+        try:
+            return self.queue.get_nowait()
+        except Empty:
+            return None
 
-        if len(iters) == 0:
-            return
+    def __iter__(self):
+        if self.iter_timeout is None:
+            timeout = ITER_TIMEOUT_SECONDS
+        else:
+            timeout = self.iter_timeout
 
         while True:
-            if len(iters) == 0:
+            message = self.get_message(True, timeout)
+            if message:
+                yield message
+            elif self.iter_timeout is None:
+                # We did not receive any message yet but we don't have a
+                # timeout, so give up the CPU for a while before trying again
+                time.sleep(NO_MESSAGES_WAIT_TIME_SECONDS)
+            else:
+                # Timed out waiting for a message
                 break
 
-            for partition, it in iters.items():
+    def _fetch(self):
+        # Create fetch request payloads for all the partitions
+        requests = []
+        partitions = self.offsets.keys()
+        while partitions:
+            for partition in partitions:
+                requests.append(FetchRequest(self.topic, partition,
+                                             self.offsets[partition],
+                                             self.buffer_size))
+            # Send request
+            responses = self.client.send_fetch_request(
+                requests,
+                max_wait_time=int(self.fetch_max_wait_time),
+                min_bytes=self.fetch_min_bytes)
+
+            retry_partitions = set()
+            for resp in responses:
+                partition = resp.partition
                 try:
-                    if self.partition_info:
-                        yield (partition, it.next())
+                    for message in resp.messages:
+                        # Update partition offset
+                        self.offsets[partition] = message.offset + 1
+
+                        # Count, check and commit messages if necessary
+                        self.count_since_commit += 1
+                        self._auto_commit()
+
+                        # Put the message in our queue
+                        if self.partition_info:
+                            self.queue.put((partition, message))
+                        else:
+                            self.queue.put(message)
+                except ConsumerFetchSizeTooSmall, e:
+                    if (self.max_buffer_size is not None and
+                            self.buffer_size == self.max_buffer_size):
+                        log.error("Max fetch size %d too small",
+                                  self.max_buffer_size)
+                        raise e
+                    if self.max_buffer_size is None:
+                        self.buffer_size *= 2
                     else:
-                        yield it.next()
+                        self.buffer_size = max(self.buffer_size * 2,
+                                               self.max_buffer_size)
+                    log.warn("Fetch size too small, increase to %d (2x) "
+                             "and retry", self.buffer_size)
+                    retry_partitions.add(partition)
+                except ConsumerNoMoreData, e:
+                    log.debug("Iteration was ended by %r", e)
                 except StopIteration:
+                    # Stop iterating through this partition
                     log.debug("Done iterating over partition %s" % partition)
-                    del iters[partition]
-
-                    # skip auto-commit since we didn't yield anything
-                    continue
-
-                # Count, check and commit messages if necessary
-                self.count_since_commit += 1
-                self._auto_commit()
-
-    def __iter_partition__(self, partition, offset):
-        """
-        Iterate over the messages in a partition. Create a FetchRequest
-        to get back a batch of messages, yield them one at a time.
-        After a batch is exhausted, start a new batch unless we've reached
-        the end of this partition.
-        """
-
-        # The offset that is stored in the consumer is the offset that
-        # we have consumed. In subsequent iterations, we are supposed to
-        # fetch the next message (that is from the next offset)
-        # However, for the 0th message, the offset should be as-is.
-        # An OffsetFetchRequest to Kafka gives 0 for a new queue. This is
-        # problematic, since 0 is offset of a message which we have not yet
-        # consumed.
-        if self.fetch_started[partition]:
-            offset += 1
-
-        fetch_size = self.fetch_min_bytes
-
-        while True:
-            # use MaxBytes = client's bufsize since we're only
-            # fetching one topic + partition
-            req = FetchRequest(
-                self.topic, partition, offset, self.client.bufsize)
-
-            (resp,) = self.client.send_fetch_request(
-                [req],
-                max_wait_time=self.fetch_max_wait_time,
-                min_bytes=fetch_size)
-
-            assert resp.topic == self.topic
-            assert resp.partition == partition
-
-            next_offset = None
-            try:
-                for message in resp.messages:
-                    next_offset = message.offset
-
-                    # update the offset before the message is yielded. This
-                    # is so that the consumer state is not lost in certain
-                    # cases.
-                    #
-                    # For eg: the message is yielded and consumed by the
-                    # caller, but the caller does not come back into the
-                    # generator again. The message will be consumed but the
-                    # status will not be updated in the consumer
-                    self.fetch_started[partition] = True
-                    self.offsets[partition] = message.offset
-                    yield message
-            except ConsumerFetchSizeTooSmall, e:
-                fetch_size *= 1.5
-                log.warn(
-                    "Fetch size too small, increasing to %d (1.5x) and retry",
-                    fetch_size)
-                continue
-            except ConsumerNoMoreData, e:
-                log.debug("Iteration was ended by %r", e)
-
-            if next_offset is None:
-                break
-            else:
-                offset = next_offset + 1
-
+                partitions = retry_partitions
 
 def _mp_consume(client, group, topic, chunk, queue, start, exit, pause, size):
     """
@@ -443,8 +449,9 @@ def _mp_consume(client, group, topic, chunk, queue, start, exit, pause, size):
         # indicates a specific number of messages, follow that advice
         count = 0
 
-        for partition, message in consumer:
-            queue.put((partition, message))
+        message = consumer.get_message()
+        if message:
+            queue.put(message)
             count += 1
 
             # We have reached the required size. The controller might have
@@ -454,12 +461,11 @@ def _mp_consume(client, group, topic, chunk, queue, start, exit, pause, size):
             # can reset the 'start' event
             if count == size.value:
                 pause.wait()
-                break
 
-        # In case we did not receive any message, give up the CPU for
-        # a while before we try again
-        if count == 0:
-            time.sleep(0.1)
+        else:
+            # In case we did not receive any message, give up the CPU for
+            # a while before we try again
+            time.sleep(NO_MESSAGES_WAIT_TIME_SECONDS)
 
     consumer.stop()
 
@@ -504,7 +510,7 @@ class MultiProcessConsumer(Consumer):
 
         # Variables for managing and controlling the data flow from
         # consumer child process to master
-        self.queue = Queue(1024)    # Child consumers dump messages into this
+        self.queue = MPQueue(1024)  # Child consumers dump messages into this
         self.start = Event()        # Indicates the consumers to start fetch
         self.exit = Event()         # Requests the consumers to shutdown
         self.pause = Event()        # Requests the consumers to pause fetch
@@ -586,8 +592,9 @@ class MultiProcessConsumer(Consumer):
 
         count: Indicates the maximum number of messages to be fetched
         block: If True, the API will block till some messages are fetched.
-        timeout: If None, and block=True, the API will block infinitely.
-                 If >0, API will block for specified time (in seconds)
+        timeout: If block is True, the function will block for the specified
+                 time (in seconds) until count messages is fetched. If None,
+                 it will block forever.
         """
         messages = []
 
@@ -598,7 +605,10 @@ class MultiProcessConsumer(Consumer):
         self.size.value = count
         self.pause.clear()
 
-        while count > 0:
+        if timeout:
+            max_time = time.time() + timeout
+
+        while count > 0 and (timeout is None or timeout > 0):
             # Trigger consumption only if the queue is empty
             # By doing this, we will ensure that consumers do not
             # go into overdrive and keep consuming thousands of
@@ -618,6 +628,7 @@ class MultiProcessConsumer(Consumer):
             self.count_since_commit += 1
             self._auto_commit()
             count -= 1
+            timeout = max_time - time.time()
 
         self.size.value = 0
         self.start.clear()
diff --git a/kafka/producer.py b/kafka/producer.py
index a82d99b..5aead43 100644
--- a/kafka/producer.py
+++ b/kafka/producer.py
@@ -69,7 +69,7 @@ def _send_upstream(topic, queue, client, batch_time, batch_size,
             client.send_produce_request(reqs,
                                         acks=req_acks,
                                         timeout=ack_timeout)
-        except Exception as exp:
+        except Exception:
             log.exception("Unable to send message")
 
 
@@ -146,9 +146,9 @@ class Producer(object):
             try:
                 resp = self.client.send_produce_request([req], acks=self.req_acks,
                                                         timeout=self.ack_timeout)
-            except Exception as e:
+            except Exception:
                 log.exception("Unable to send messages")
-                raise e
+                raise
         return resp
 
     def stop(self, timeout=1):
diff --git a/kafka/protocol.py b/kafka/protocol.py
index 612acf6..54b8eee 100644
--- a/kafka/protocol.py
+++ b/kafka/protocol.py
@@ -119,9 +119,17 @@ class KafkaProtocol(object):
                     read_message = True
                     yield OffsetAndMessage(offset, message)
             except BufferUnderflowError:
+                # NOTE: Not sure this is correct error handling:
+                # Is it possible to get a BUE if the message set is somewhere
+                # in the middle of the fetch response? If so, we probably have
+                # an issue that's not fetch size too small.
+                # Aren't we ignoring errors if we fail to unpack data by
+                # raising StopIteration()?
+                # If _decode_message() raises a ChecksumError, couldn't that
+                # also be due to the fetch size being too small?
                 if read_message is False:
                     # If we get a partial read of a message, but haven't
-                    # yielded anyhting there's a problem
+                    # yielded anything there's a problem
                     raise ConsumerFetchSizeTooSmall()
                 else:
                     raise StopIteration()
@@ -171,7 +179,7 @@ class KafkaProtocol(object):
         Params
         ======
         client_id: string
-        correlation_id: string
+        correlation_id: int
         payloads: list of ProduceRequest
         acks: How "acky" you want the request to be
             0: immediate response
@@ -231,7 +239,7 @@ class KafkaProtocol(object):
         Params
         ======
         client_id: string
-        correlation_id: string
+        correlation_id: int
         payloads: list of FetchRequest
         max_wait_time: int, how long to block waiting on min_bytes of data
         min_bytes: int, the minimum number of bytes to accumulate before
@@ -338,7 +346,7 @@ class KafkaProtocol(object):
         Params
         ======
         client_id: string
-        correlation_id: string
+        correlation_id: int
         topics: list of strings
         """
         topics = [] if topics is None else topics
@@ -376,12 +384,16 @@ class KafkaProtocol(object):
         topic_metadata = {}
 
         for i in range(num_topics):
+            # NOTE: topic_error is discarded. Should probably be returned with
+            # the topic metadata.
             ((topic_error,), cur) = relative_unpack('>h', data, cur)
             (topic_name, cur) = read_short_string(data, cur)
             ((num_partitions,), cur) = relative_unpack('>i', data, cur)
             partition_metadata = {}
 
             for j in range(num_partitions):
+                # NOTE: partition_error_code is discarded. Should probably be
+                # returned with the partition metadata.
                 ((partition_error_code, partition, leader, numReplicas), cur) = \
                     relative_unpack('>hiii', data, cur)
 
@@ -408,7 +420,7 @@ class KafkaProtocol(object):
         Params
         ======
         client_id: string
-        correlation_id: string
+        correlation_id: int
         group: string, the consumer group you are committing offsets for
         payloads: list of OffsetCommitRequest
         """
@@ -459,7 +471,7 @@ class KafkaProtocol(object):
         Params
         ======
         client_id: string
-        correlation_id: string
+        correlation_id: int
         group: string, the consumer group you are fetching offsets for
         payloads: list of OffsetFetchRequest
         """
diff --git a/test/fixtures.py b/test/fixtures.py
index c771a58..9e283d3 100644
--- a/test/fixtures.py
+++ b/test/fixtures.py
@@ -208,9 +208,12 @@ class ZookeeperFixture(object):
         self.tmp_dir = None
         self.child = None
 
+    def out(self, message):
+        print("*** Zookeeper [%s:%d]: %s" % (self.host, self.port, message))
+
     def open(self):
         self.tmp_dir = tempfile.mkdtemp()
-        print("*** Running local Zookeeper instance...")
+        self.out("Running local instance...")
         print("  host    = %s" % self.host)
         print("  port    = %s" % self.port)
         print("  tmp_dir = %s" % self.tmp_dir)
@@ -229,16 +232,16 @@ class ZookeeperFixture(object):
         self.child.configure_stderr(os.path.join(self.tmp_dir, "stderr.txt"))
 
         # Party!
-        print("*** Starting Zookeeper...")
+        self.out("Starting...")
         self.child.start()
         self.child.wait_for(r"Snapshotting")
-        print("*** Done!")
+        self.out("Done!")
 
     def close(self):
-        print("*** Stopping Zookeeper...")
+        self.out("Stopping...")
         self.child.stop()
         self.child = None
-        print("*** Done!")
+        self.out("Done!")
         shutil.rmtree(self.tmp_dir)
 
 
@@ -272,10 +275,18 @@ class KafkaFixture(object):
 
         self.tmp_dir = None
         self.child = None
+        self.running = False
+
+    def out(self, message):
+        print("*** Kafka [%s:%d]: %s" % (self.host, self.port, message))
 
     def open(self):
+        if self.running:
+            self.out("Instance already running")
+            return
+
         self.tmp_dir = tempfile.mkdtemp()
-        print("*** Running local Kafka instance")
+        self.out("Running local instance...")
         print("  host       = %s" % self.host)
         print("  port       = %s" % self.port)
         print("  broker_id  = %s" % self.broker_id)
@@ -303,25 +314,31 @@ class KafkaFixture(object):
         self.child.configure_stderr(os.path.join(self.tmp_dir, "stderr.txt"))
 
         # Party!
-        print("*** Creating Zookeeper chroot node...")
+        self.out("Creating Zookeeper chroot node...")
         proc = subprocess.Popen(kafka_run_class_args(
             "org.apache.zookeeper.ZooKeeperMain",
             "-server", "%s:%d" % (self.zk_host, self.zk_port),
             "create", "/%s" % self.zk_chroot, "kafka-python"
         ))
         if proc.wait() != 0:
-            print("*** Failed to create Zookeeper chroot node")
+            self.out("Failed to create Zookeeper chroot node")
             raise RuntimeError("Failed to create Zookeeper chroot node")
-        print("*** Done!")
+        self.out("Done!")
 
-        print("*** Starting Kafka...")
+        self.out("Starting...")
         self.child.start()
         self.child.wait_for(r"\[Kafka Server %d\], Started" % self.broker_id)
-        print("*** Done!")
+        self.out("Done!")
+        self.running = True
 
     def close(self):
-        print("*** Stopping Kafka...")
+        if not self.running:
+            self.out("Instance already stopped")
+            return
+
+        self.out("Stopping...")
         self.child.stop()
         self.child = None
-        print("*** Done!")
+        self.out("Done!")
         shutil.rmtree(self.tmp_dir)
+        self.running = False
diff --git a/test/test_integration.py b/test/test_integration.py
index a10dae2..eaf432d 100644
--- a/test/test_integration.py
+++ b/test/test_integration.py
@@ -8,6 +8,7 @@ import random
 from kafka import *  # noqa
 from kafka.common import *  # noqa
 from kafka.codec import has_gzip, has_snappy
+from kafka.consumer import MAX_FETCH_BUFFER_SIZE_BYTES
 from .fixtures import ZookeeperFixture, KafkaFixture
 
 
@@ -554,7 +555,7 @@ class TestConsumer(unittest.TestCase):
         cls.zk = ZookeeperFixture.instance()
         cls.server1 = KafkaFixture.instance(0, cls.zk.host, cls.zk.port)
         cls.server2 = KafkaFixture.instance(1, cls.zk.host, cls.zk.port)
-        cls.client = KafkaClient(cls.server2.host, cls.server2.port, bufsize=8192)
+        cls.client = KafkaClient(cls.server2.host, cls.server2.port)
 
     @classmethod
     def tearDownClass(cls):  # noqa
@@ -583,7 +584,9 @@ class TestConsumer(unittest.TestCase):
             self.assertEquals(resp.offset, 0)
 
         # Start a consumer
-        consumer = SimpleConsumer(self.client, "group1", "test_simple_consumer", auto_commit=False)
+        consumer = SimpleConsumer(self.client, "group1",
+                                  "test_simple_consumer", auto_commit=False,
+                                  iter_timeout=0)
         all_messages = []
         for message in consumer:
             all_messages.append(message)
@@ -609,7 +612,9 @@ class TestConsumer(unittest.TestCase):
         consumer.stop()
 
     def test_simple_consumer_blocking(self):
-        consumer = SimpleConsumer(self.client, "group1", "test_simple_consumer_blocking", auto_commit=False)
+        consumer = SimpleConsumer(self.client, "group1",
+                                  "test_simple_consumer_blocking",
+                                  auto_commit=False, iter_timeout=0)
 
         # Blocking API
         start = datetime.now()
@@ -657,7 +662,8 @@ class TestConsumer(unittest.TestCase):
             self.assertEquals(resp.error, 0)
             self.assertEquals(resp.offset, 0)
 
-        consumer = SimpleConsumer(self.client, "group1", "test_simple_pending", auto_commit=False)
+        consumer = SimpleConsumer(self.client, "group1", "test_simple_pending",
+                                  auto_commit=False, iter_timeout=0)
         self.assertEquals(consumer.pending(), 20)
         self.assertEquals(consumer.pending(partitions=[0]), 10)
         self.assertEquals(consumer.pending(partitions=[1]), 10)
@@ -755,7 +761,7 @@ class TestConsumer(unittest.TestCase):
             self.assertEquals(resp.error, 0)
             self.assertEquals(resp.offset, 0)
 
-        # Produce 10 messages that are too large (bigger than default fetch size)
+        # Produce 10 messages that are large (bigger than default fetch size)
         messages2 = [create_message(random_string(5000)) for i in range(10)]
         produce2 = ProduceRequest("test_large_messages", 0, messages2)
 
@@ -764,33 +770,55 @@ class TestConsumer(unittest.TestCase):
             self.assertEquals(resp.offset, 10)
 
         # Consumer should still get all of them
-        consumer = SimpleConsumer(self.client, "group1", "test_large_messages", auto_commit=False)
+        consumer = SimpleConsumer(self.client, "group1", "test_large_messages",
+                                  auto_commit=False, iter_timeout=0)
         all_messages = messages1 + messages2
         for i, message in enumerate(consumer):
             self.assertEquals(all_messages[i], message.message)
         self.assertEquals(i, 19)
 
+        # Produce 1 message that is too large (bigger than max fetch size)
+        big_message_size = MAX_FETCH_BUFFER_SIZE_BYTES + 10
+        big_message = create_message(random_string(big_message_size))
+        produce3 = ProduceRequest("test_large_messages", 0, [big_message])
+        for resp in self.client.send_produce_request([produce3]):
+            self.assertEquals(resp.error, 0)
+            self.assertEquals(resp.offset, 20)
+
+        self.assertRaises(ConsumerFetchSizeTooSmall, consumer.get_message, False, 0.1)
+
+        # Create a consumer with no fetch size limit
+        big_consumer = SimpleConsumer(self.client, "group1", "test_large_messages",
+                                      max_buffer_size=None, partitions=[0],
+                                      auto_commit=False, iter_timeout=0)
+
+        # Seek to the last message
+        big_consumer.seek(-1, 2)
+
+        # Consume giant message successfully
+        message = big_consumer.get_message(block=False, timeout=10)
+        self.assertIsNotNone(message)
+        self.assertEquals(message.message.value, big_message.value)
+
 class TestFailover(unittest.TestCase):
 
-    @classmethod
-    def setUpClass(cls):
+    def setUp(self):
 
-        zk_chroot = random_string(10)
+        zk_chroot  = random_string(10)
         replicas   = 2
         partitions = 2
 
         # mini zookeeper, 2 kafka brokers
-        cls.zk      = ZookeeperFixture.instance()
-        kk_args     = [cls.zk.host, cls.zk.port, zk_chroot, replicas, partitions]
-        cls.brokers = [KafkaFixture.instance(i, *kk_args) for i in range(replicas)]
-        cls.client  = KafkaClient(cls.brokers[0].host, cls.brokers[0].port)
-
-    @classmethod
-    def tearDownClass(cls):
-        cls.client.close()
-        for broker in cls.brokers:
+        self.zk      = ZookeeperFixture.instance()
+        kk_args      = [self.zk.host, self.zk.port, zk_chroot, replicas, partitions]
+        self.brokers = [KafkaFixture.instance(i, *kk_args) for i in range(replicas)]
+        self.client  = KafkaClient(self.brokers[0].host, self.brokers[0].port)
+
+    def tearDown(self):
+        self.client.close()
+        for broker in self.brokers:
             broker.close()
-        cls.zk.close()
+        self.zk.close()
 
     def test_switch_leader(self):
 
@@ -869,7 +897,7 @@ class TestFailover(unittest.TestCase):
 
     def _count_messages(self, group, topic):
         client   = KafkaClient(self.brokers[0].host, self.brokers[0].port)
-        consumer = SimpleConsumer(client, group, topic, auto_commit=False)
+        consumer = SimpleConsumer(client, group, topic, auto_commit=False, iter_timeout=0)
         all_messages = []
         for message in consumer:
             all_messages.append(message)
diff --git a/test/test_unit.py b/test/test_unit.py
index 3f3af66..e3fd4bb 100644
--- a/test/test_unit.py
+++ b/test/test_unit.py
@@ -3,13 +3,18 @@ import random
 import struct
 import unittest
 
-from kafka.client import KafkaClient
-from kafka.common import ProduceRequest, FetchRequest
+from kafka.common import (
+    ProduceRequest, FetchRequest, Message, ChecksumError,
+    ConsumerFetchSizeTooSmall, ProduceResponse, FetchResponse,
+    OffsetAndMessage, BrokerMetadata, PartitionMetadata
+)
 from kafka.codec import (
-    has_gzip, has_snappy,
-    gzip_encode, gzip_decode,
+    has_gzip, has_snappy, gzip_encode, gzip_decode,
     snappy_encode, snappy_decode
 )
+from kafka.protocol import (
+    create_gzip_message, create_message, create_snappy_message, KafkaProtocol
+)
 
 ITERATIONS = 1000
 STRLEN = 100
@@ -20,16 +25,13 @@ def random_string():
 
 
 class TestPackage(unittest.TestCase):
-    @unittest.expectedFailure
+
     def test_top_level_namespace(self):
         import kafka as kafka1
         self.assertEquals(kafka1.KafkaClient.__name__, "KafkaClient")
-        self.assertEquals(kafka1.gzip_encode.__name__, "gzip_encode")
-        self.assertEquals(kafka1.snappy_encode.__name__, "snappy_encode")
         self.assertEquals(kafka1.client.__name__, "kafka.client")
         self.assertEquals(kafka1.codec.__name__, "kafka.codec")
 
-    @unittest.expectedFailure
     def test_submodule_namespace(self):
         import kafka.client as client1
         self.assertEquals(client1.__name__, "kafka.client")
@@ -48,173 +50,334 @@ class TestPackage(unittest.TestCase):
         from kafka import KafkaClient as KafkaClient2
         self.assertEquals(KafkaClient2.__name__, "KafkaClient")
 
-        from kafka import gzip_encode as gzip_encode2
-        self.assertEquals(gzip_encode2.__name__, "gzip_encode")
-
-        from kafka import snappy_encode as snappy_encode2
-        self.assertEquals(snappy_encode2.__name__, "snappy_encode")
-
-
-class TestMisc(unittest.TestCase):
-    @unittest.expectedFailure
-    def test_length_prefix(self):
-        for i in xrange(ITERATIONS):
-            s1 = random_string()
-            self.assertEquals(struct.unpack('>i', s2[0:4])[0], len(s1))
+        from kafka.codec import snappy_encode
+        self.assertEquals(snappy_encode.__name__, "snappy_encode")
 
 
 class TestCodec(unittest.TestCase):
+
+    @unittest.skipUnless(has_gzip(), "Gzip not available")
     def test_gzip(self):
-        if not has_gzip():
-            return
         for i in xrange(ITERATIONS):
             s1 = random_string()
             s2 = gzip_decode(gzip_encode(s1))
             self.assertEquals(s1, s2)
 
+    @unittest.skipUnless(has_snappy(), "Snappy not available")
     def test_snappy(self):
-        if not has_snappy():
-            return
         for i in xrange(ITERATIONS):
             s1 = random_string()
             s2 = snappy_decode(snappy_encode(s1))
             self.assertEquals(s1, s2)
 
 
-# XXX(sandello): These really should be protocol tests.
-class TestMessage(unittest.TestCase):
-    @unittest.expectedFailure
-    def test_create(self):
-        msg = KafkaClient.create_message("testing")
-        self.assertEquals(msg.payload, "testing")
-        self.assertEquals(msg.magic, 1)
-        self.assertEquals(msg.attributes, 0)
-        self.assertEquals(msg.crc, -386704890)
+class TestProtocol(unittest.TestCase):
+
+    def test_create_message(self):
+        payload = "test"
+        key = "key"
+        msg = create_message(payload, key)
+        self.assertEqual(msg.magic, 0)
+        self.assertEqual(msg.attributes, 0)
+        self.assertEqual(msg.key, key)
+        self.assertEqual(msg.value, payload)
 
-    @unittest.expectedFailure
+    @unittest.skipUnless(has_gzip(), "Snappy not available")
     def test_create_gzip(self):
-        msg = KafkaClient.create_gzip_message("testing")
-        self.assertEquals(msg.magic, 1)
-        self.assertEquals(msg.attributes, 1)
-        # Can't check the crc or payload for gzip since it's non-deterministic
-        (messages, _) = KafkaClient.read_message_set(gzip_decode(msg.payload))
-        inner = messages[0]
-        self.assertEquals(inner.magic, 1)
-        self.assertEquals(inner.attributes, 0)
-        self.assertEquals(inner.payload, "testing")
-        self.assertEquals(inner.crc, -386704890)
-
-    @unittest.expectedFailure
+        payloads = ["v1", "v2"]
+        msg = create_gzip_message(payloads)
+        self.assertEqual(msg.magic, 0)
+        self.assertEqual(msg.attributes, KafkaProtocol.ATTRIBUTE_CODEC_MASK &
+                                         KafkaProtocol.CODEC_GZIP)
+        self.assertEqual(msg.key, None)
+        # Need to decode to check since gzipped payload is non-deterministic
+        decoded = gzip_decode(msg.value)
+        expect = ("\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x10L\x9f[\xc2"
+                  "\x00\x00\xff\xff\xff\xff\x00\x00\x00\x02v1\x00\x00\x00\x00"
+                  "\x00\x00\x00\x00\x00\x00\x00\x10\xd5\x96\nx\x00\x00\xff\xff"
+                  "\xff\xff\x00\x00\x00\x02v2")
+        self.assertEqual(decoded, expect)
+
+    @unittest.skipUnless(has_snappy(), "Snappy not available")
     def test_create_snappy(self):
-        msg = KafkaClient.create_snappy_message("testing")
-        self.assertEquals(msg.magic, 1)
-        self.assertEquals(msg.attributes, 2)
-        self.assertEquals(msg.crc, -62350868)
-        (messages, _) = KafkaClient.read_message_set(snappy_decode(msg.payload))
-        inner = messages[0]
-        self.assertEquals(inner.magic, 1)
-        self.assertEquals(inner.attributes, 0)
-        self.assertEquals(inner.payload, "testing")
-        self.assertEquals(inner.crc, -386704890)
-
-    @unittest.expectedFailure
-    def test_message_simple(self):
-        msg = KafkaClient.create_message("testing")
-        enc = KafkaClient.encode_message(msg)
-        expect = "\x00\x00\x00\r\x01\x00\xe8\xf3Z\x06testing"
-        self.assertEquals(enc, expect)
-        (messages, read) = KafkaClient.read_message_set(enc)
-        self.assertEquals(len(messages), 1)
-        self.assertEquals(messages[0], msg)
-
-    @unittest.expectedFailure
-    def test_message_list(self):
-        msgs = [
-            KafkaClient.create_message("one"),
-            KafkaClient.create_message("two"),
-            KafkaClient.create_message("three")
-        ]
-        enc = KafkaClient.encode_message_set(msgs)
-        expect = ("\x00\x00\x00\t\x01\x00zl\x86\xf1one\x00\x00\x00\t\x01\x00\x11"
-                  "\xca\x8aftwo\x00\x00\x00\x0b\x01\x00F\xc5\xd8\xf5three")
-        self.assertEquals(enc, expect)
-        (messages, read) = KafkaClient.read_message_set(enc)
-        self.assertEquals(len(messages), 3)
-        self.assertEquals(messages[0].payload, "one")
-        self.assertEquals(messages[1].payload, "two")
-        self.assertEquals(messages[2].payload, "three")
-
-    @unittest.expectedFailure
-    def test_message_gzip(self):
-        msg = KafkaClient.create_gzip_message("one", "two", "three")
-        enc = KafkaClient.encode_message(msg)
-        # Can't check the bytes directly since Gzip is non-deterministic
-        (messages, read) = KafkaClient.read_message_set(enc)
-        self.assertEquals(len(messages), 3)
-        self.assertEquals(messages[0].payload, "one")
-        self.assertEquals(messages[1].payload, "two")
-        self.assertEquals(messages[2].payload, "three")
-
-    @unittest.expectedFailure
-    def test_message_snappy(self):
-        msg = KafkaClient.create_snappy_message("one", "two", "three")
-        enc = KafkaClient.encode_message(msg)
-        (messages, read) = KafkaClient.read_message_set(enc)
-        self.assertEquals(len(messages), 3)
-        self.assertEquals(messages[0].payload, "one")
-        self.assertEquals(messages[1].payload, "two")
-        self.assertEquals(messages[2].payload, "three")
-
-    @unittest.expectedFailure
-    def test_message_simple_random(self):
-        for i in xrange(ITERATIONS):
-            n = random.randint(0, 10)
-            msgs = [KafkaClient.create_message(random_string()) for j in range(n)]
-            enc = KafkaClient.encode_message_set(msgs)
-            (messages, read) = KafkaClient.read_message_set(enc)
-            self.assertEquals(len(messages), n)
-            for j in range(n):
-                self.assertEquals(messages[j], msgs[j])
-
-    @unittest.expectedFailure
-    def test_message_gzip_random(self):
-        for i in xrange(ITERATIONS):
-            n = random.randint(1, 10)
-            strings = [random_string() for j in range(n)]
-            msg = KafkaClient.create_gzip_message(*strings)
-            enc = KafkaClient.encode_message(msg)
-            (messages, read) = KafkaClient.read_message_set(enc)
-            self.assertEquals(len(messages), n)
-            for j in range(n):
-                self.assertEquals(messages[j].payload, strings[j])
-
-    @unittest.expectedFailure
-    def test_message_snappy_random(self):
-        for i in xrange(ITERATIONS):
-            n = random.randint(1, 10)
-            strings = [random_string() for j in range(n)]
-            msg = KafkaClient.create_snappy_message(*strings)
-            enc = KafkaClient.encode_message(msg)
-            (messages, read) = KafkaClient.read_message_set(enc)
-            self.assertEquals(len(messages), n)
-            for j in range(n):
-                self.assertEquals(messages[j].payload, strings[j])
-
-
-class TestRequests(unittest.TestCase):
-    @unittest.expectedFailure
-    def test_produce_request(self):
-        req = ProduceRequest("my-topic", 0, [KafkaClient.create_message("testing")])
-        enc = KafkaClient.encode_produce_request(req)
-        expect = "\x00\x00\x00\x08my-topic\x00\x00\x00\x00\x00\x00\x00\x11\x00\x00\x00\r\x01\x00\xe8\xf3Z\x06testing"
-        self.assertEquals(enc, expect)
-
-    @unittest.expectedFailure
-    def test_fetch_request(self):
-        req = FetchRequest("my-topic", 0, 0, 1024)
-        enc = KafkaClient.encode_fetch_request(req)
-        expect = "\x00\x01\x00\x08my-topic\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x04\x00"
-        self.assertEquals(enc, expect)
+        payloads = ["v1", "v2"]
+        msg = create_snappy_message(payloads)
+        self.assertEqual(msg.magic, 0)
+        self.assertEqual(msg.attributes, KafkaProtocol.ATTRIBUTE_CODEC_MASK &
+                                         KafkaProtocol.CODEC_SNAPPY)
+        self.assertEqual(msg.key, None)
+        expect = ("8\x00\x00\x19\x01@\x10L\x9f[\xc2\x00\x00\xff\xff\xff\xff"
+                  "\x00\x00\x00\x02v1\x19\x1bD\x00\x10\xd5\x96\nx\x00\x00\xff"
+                  "\xff\xff\xff\x00\x00\x00\x02v2")
+        self.assertEqual(msg.value, expect)
+
+    def test_encode_message_header(self):
+        expect = '\x00\n\x00\x00\x00\x00\x00\x04\x00\x07client3'
+        encoded = KafkaProtocol._encode_message_header("client3", 4, 10)
+        self.assertEqual(encoded, expect)
+
+    def test_encode_message(self):
+        message = create_message("test", "key")
+        encoded = KafkaProtocol._encode_message(message)
+        expect = "\xaa\xf1\x8f[\x00\x00\x00\x00\x00\x03key\x00\x00\x00\x04test"
+        self.assertEqual(encoded, expect)
+
+    def test_encode_message_failure(self):
+        self.assertRaises(Exception, KafkaProtocol._encode_message,
+                          Message(1, 0, "key", "test"))
+
+    def test_encode_message_set(self):
+        message_set = [create_message("v1", "k1"), create_message("v2", "k2")]
+        encoded = KafkaProtocol._encode_message_set(message_set)
+        expect = ("\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x12W\xe7In\x00"
+                  "\x00\x00\x00\x00\x02k1\x00\x00\x00\x02v1\x00\x00\x00\x00"
+                  "\x00\x00\x00\x00\x00\x00\x00\x12\xff\x06\x02I\x00\x00\x00"
+                  "\x00\x00\x02k2\x00\x00\x00\x02v2")
+        self.assertEqual(encoded, expect)
+
+    def test_decode_message(self):
+        encoded = "\xaa\xf1\x8f[\x00\x00\x00\x00\x00\x03key\x00\x00\x00\x04test"
+        offset = 10
+        (returned_offset, decoded_message) = \
+            list(KafkaProtocol._decode_message(encoded, offset))[0]
+        self.assertEqual(returned_offset, offset)
+        self.assertEqual(decoded_message, create_message("test", "key"))
+
+    def test_decode_message_set(self):
+        encoded = ('\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x10L\x9f[\xc2'
+                   '\x00\x00\xff\xff\xff\xff\x00\x00\x00\x02v1\x00\x00\x00\x00'
+                   '\x00\x00\x00\x00\x00\x00\x00\x10\xd5\x96\nx\x00\x00\xff'
+                   '\xff\xff\xff\x00\x00\x00\x02v2')
+        iter = KafkaProtocol._decode_message_set_iter(encoded)
+        decoded = list(iter)
+        self.assertEqual(len(decoded), 2)
+        (returned_offset1, decoded_message1) = decoded[0]
+        self.assertEqual(returned_offset1, 0)
+        self.assertEqual(decoded_message1, create_message("v1"))
+        (returned_offset2, decoded_message2) = decoded[1]
+        self.assertEqual(returned_offset2, 0)
+        self.assertEqual(decoded_message2, create_message("v2"))
+
+    @unittest.skipUnless(has_gzip(), "Gzip not available")
+    def test_decode_message_gzip(self):
+        gzip_encoded = ('\xc0\x11\xb2\xf0\x00\x01\xff\xff\xff\xff\x00\x00\x000'
+                        '\x1f\x8b\x08\x00\xa1\xc1\xc5R\x02\xffc`\x80\x03\x01'
+                        '\x9f\xf9\xd1\x87\x18\x18\xfe\x03\x01\x90\xc7Tf\xc8'
+                        '\x80$wu\x1aW\x05\x92\x9c\x11\x00z\xc0h\x888\x00\x00'
+                        '\x00')
+        offset = 11
+        decoded = list(KafkaProtocol._decode_message(gzip_encoded, offset))
+        self.assertEqual(len(decoded), 2)
+        (returned_offset1, decoded_message1) = decoded[0]
+        self.assertEqual(returned_offset1, 0)
+        self.assertEqual(decoded_message1, create_message("v1"))
+        (returned_offset2, decoded_message2) = decoded[1]
+        self.assertEqual(returned_offset2, 0)
+        self.assertEqual(decoded_message2, create_message("v2"))
+
+    @unittest.skipUnless(has_snappy(), "Snappy not available")
+    def test_decode_message_snappy(self):
+        snappy_encoded = ('\xec\x80\xa1\x95\x00\x02\xff\xff\xff\xff\x00\x00'
+                          '\x00,8\x00\x00\x19\x01@\x10L\x9f[\xc2\x00\x00\xff'
+                          '\xff\xff\xff\x00\x00\x00\x02v1\x19\x1bD\x00\x10\xd5'
+                          '\x96\nx\x00\x00\xff\xff\xff\xff\x00\x00\x00\x02v2')
+        offset = 11
+        decoded = list(KafkaProtocol._decode_message(snappy_encoded, offset))
+        self.assertEqual(len(decoded), 2)
+        (returned_offset1, decoded_message1) = decoded[0]
+        self.assertEqual(returned_offset1, 0)
+        self.assertEqual(decoded_message1, create_message("v1"))
+        (returned_offset2, decoded_message2) = decoded[1]
+        self.assertEqual(returned_offset2, 0)
+        self.assertEqual(decoded_message2, create_message("v2"))
+
+    def test_decode_message_checksum_error(self):
+        invalid_encoded_message = "This is not a valid encoded message"
+        iter = KafkaProtocol._decode_message(invalid_encoded_message, 0)
+        self.assertRaises(ChecksumError, list, iter)
+
+    # NOTE: The error handling in _decode_message_set_iter() is questionable.
+    # If it's modified, the next two tests might need to be fixed.
+    def test_decode_message_set_fetch_size_too_small(self):
+        iter = KafkaProtocol._decode_message_set_iter('a')
+        self.assertRaises(ConsumerFetchSizeTooSmall, list, iter)
+
+    def test_decode_message_set_stop_iteration(self):
+        encoded = ('\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x10L\x9f[\xc2'
+                   '\x00\x00\xff\xff\xff\xff\x00\x00\x00\x02v1\x00\x00\x00\x00'
+                   '\x00\x00\x00\x00\x00\x00\x00\x10\xd5\x96\nx\x00\x00\xff'
+                   '\xff\xff\xff\x00\x00\x00\x02v2')
+        iter = KafkaProtocol._decode_message_set_iter(encoded + "@#$%(Y!")
+        decoded = list(iter)
+        self.assertEqual(len(decoded), 2)
+        (returned_offset1, decoded_message1) = decoded[0]
+        self.assertEqual(returned_offset1, 0)
+        self.assertEqual(decoded_message1, create_message("v1"))
+        (returned_offset2, decoded_message2) = decoded[1]
+        self.assertEqual(returned_offset2, 0)
+        self.assertEqual(decoded_message2, create_message("v2"))
+
+    def test_encode_produce_request(self):
+        requests = [ProduceRequest("topic1", 0, [create_message("a"),
+                                                 create_message("b")]),
+                    ProduceRequest("topic2", 1, [create_message("c")])]
+        expect = ('\x00\x00\x00\x94\x00\x00\x00\x00\x00\x00\x00\x02\x00\x07'
+                  'client1\x00\x02\x00\x00\x00d\x00\x00\x00\x02\x00\x06topic1'
+                  '\x00\x00\x00\x01\x00\x00\x00\x00\x00\x00\x006\x00\x00\x00'
+                  '\x00\x00\x00\x00\x00\x00\x00\x00\x0fQ\xdf:2\x00\x00\xff\xff'
+                  '\xff\xff\x00\x00\x00\x01a\x00\x00\x00\x00\x00\x00\x00\x00'
+                  '\x00\x00\x00\x0f\xc8\xd6k\x88\x00\x00\xff\xff\xff\xff\x00'
+                  '\x00\x00\x01b\x00\x06topic2\x00\x00\x00\x01\x00\x00\x00\x01'
+                  '\x00\x00\x00\x1b\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00'
+                  '\x00\x0f\xbf\xd1[\x1e\x00\x00\xff\xff\xff\xff\x00\x00\x00'
+                  '\x01c')
+        encoded = KafkaProtocol.encode_produce_request("client1", 2, requests,
+                                                       2, 100)
+        self.assertEqual(encoded, expect)
+
+    def test_decode_produce_response(self):
+        t1 = "topic1"
+        t2 = "topic2"
+        encoded = struct.pack('>iih%dsiihqihqh%dsiihq' % (len(t1), len(t2)),
+                              2, 2, len(t1), t1, 2, 0, 0, 10L, 1, 1, 20L,
+                              len(t2), t2, 1, 0, 0, 30L)
+        responses = list(KafkaProtocol.decode_produce_response(encoded))
+        self.assertEqual(responses,
+                         [ProduceResponse(t1, 0, 0, 10L),
+                          ProduceResponse(t1, 1, 1, 20L),
+                          ProduceResponse(t2, 0, 0, 30L)])
+
+    def test_encode_fetch_request(self):
+        requests = [FetchRequest("topic1", 0, 10, 1024),
+                    FetchRequest("topic2", 1, 20, 100)]
+        expect = ('\x00\x00\x00Y\x00\x01\x00\x00\x00\x00\x00\x03\x00\x07'
+                  'client1\xff\xff\xff\xff\x00\x00\x00\x02\x00\x00\x00d\x00'
+                  '\x00\x00\x02\x00\x06topic1\x00\x00\x00\x01\x00\x00\x00\x00'
+                  '\x00\x00\x00\x00\x00\x00\x00\n\x00\x00\x04\x00\x00\x06'
+                  'topic2\x00\x00\x00\x01\x00\x00\x00\x01\x00\x00\x00\x00\x00'
+                  '\x00\x00\x14\x00\x00\x00d')
+        encoded = KafkaProtocol.encode_fetch_request("client1", 3, requests, 2,
+                                                     100)
+        self.assertEqual(encoded, expect)
+
+    def test_decode_fetch_response(self):
+        t1 = "topic1"
+        t2 = "topic2"
+        msgs = map(create_message, ["message1", "hi", "boo", "foo", "so fun!"])
+        ms1 = KafkaProtocol._encode_message_set([msgs[0], msgs[1]])
+        ms2 = KafkaProtocol._encode_message_set([msgs[2]])
+        ms3 = KafkaProtocol._encode_message_set([msgs[3], msgs[4]])
+
+        encoded = struct.pack('>iih%dsiihqi%dsihqi%dsh%dsiihqi%ds' %
+                              (len(t1), len(ms1), len(ms2), len(t2), len(ms3)),
+                              4, 2, len(t1), t1, 2, 0, 0, 10, len(ms1), ms1, 1,
+                              1, 20, len(ms2), ms2, len(t2), t2, 1, 0, 0, 30,
+                              len(ms3), ms3)
+
+        responses = list(KafkaProtocol.decode_fetch_response(encoded))
+        def expand_messages(response):
+            return FetchResponse(response.topic, response.partition,
+                                 response.error, response.highwaterMark,
+                                 list(response.messages))
+
+        expanded_responses = map(expand_messages, responses)
+        expect = [FetchResponse(t1, 0, 0, 10, [OffsetAndMessage(0, msgs[0]),
+                                               OffsetAndMessage(0, msgs[1])]),
+                  FetchResponse(t1, 1, 1, 20, [OffsetAndMessage(0, msgs[2])]),
+                  FetchResponse(t2, 0, 0, 30, [OffsetAndMessage(0, msgs[3]),
+                                               OffsetAndMessage(0, msgs[4])])]
+        self.assertEqual(expanded_responses, expect)
+
+    def test_encode_metadata_request_no_topics(self):
+        encoded = KafkaProtocol.encode_metadata_request("cid", 4)
+        self.assertEqual(encoded, '\x00\x00\x00\x11\x00\x03\x00\x00\x00\x00'
+                                  '\x00\x04\x00\x03cid\x00\x00\x00\x00')
+
+    def test_encode_metadata_request_with_topics(self):
+        encoded = KafkaProtocol.encode_metadata_request("cid", 4, ["t1", "t2"])
+        self.assertEqual(encoded, '\x00\x00\x00\x19\x00\x03\x00\x00\x00\x00'
+                                  '\x00\x04\x00\x03cid\x00\x00\x00\x02\x00\x02'
+                                  't1\x00\x02t2')
+
+    def _create_encoded_metadata_response(self, broker_data, topic_data,
+                                          topic_errors, partition_errors):
+        encoded = struct.pack('>ii', 3, len(broker_data))
+        for node_id, broker in broker_data.iteritems():
+            encoded += struct.pack('>ih%dsi' % len(broker.host), node_id,
+                                   len(broker.host), broker.host, broker.port)
+
+        encoded += struct.pack('>i', len(topic_data))
+        for topic, partitions in topic_data.iteritems():
+            encoded += struct.pack('>hh%dsi' % len(topic), topic_errors[topic],
+                                   len(topic), topic, len(partitions))
+            for partition, metadata in partitions.iteritems():
+                encoded += struct.pack('>hiii',
+                                       partition_errors[(topic, partition)],
+                                       partition, metadata.leader,
+                                       len(metadata.replicas))
+                if len(metadata.replicas) > 0:
+                    encoded += struct.pack('>%di' % len(metadata.replicas),
+                                           *metadata.replicas)
+
+                encoded += struct.pack('>i', len(metadata.isr))
+                if len(metadata.isr) > 0:
+                    encoded += struct.pack('>%di' % len(metadata.isr),
+                                           *metadata.isr)
+
+        return encoded
+
+    def test_decode_metadata_response(self):
+        node_brokers = {
+            0: BrokerMetadata(0, "brokers1.kafka.rdio.com", 1000),
+            1: BrokerMetadata(1, "brokers1.kafka.rdio.com", 1001),
+            3: BrokerMetadata(3, "brokers2.kafka.rdio.com", 1000)
+        }
+        topic_partitions = {
+            "topic1": {
+                0: PartitionMetadata("topic1", 0, 1, (0, 2), (2,)),
+                1: PartitionMetadata("topic1", 1, 3, (0, 1), (0, 1))
+            },
+            "topic2": {
+                0: PartitionMetadata("topic2", 0, 0, (), ())
+            }
+        }
+        topic_errors = {"topic1": 0, "topic2": 1}
+        partition_errors = {
+            ("topic1", 0): 0,
+            ("topic1", 1): 1,
+            ("topic2", 0): 0
+        }
+        encoded = self._create_encoded_metadata_response(node_brokers,
+                                                         topic_partitions,
+                                                         topic_errors,
+                                                         partition_errors)
+        decoded = KafkaProtocol.decode_metadata_response(encoded)
+        self.assertEqual(decoded, (node_brokers, topic_partitions))
+
+    @unittest.skip("Not Implemented")
+    def test_encode_offset_request(self):
+        pass
+
+    @unittest.skip("Not Implemented")
+    def test_decode_offset_response(self):
+        pass
+
+
+    @unittest.skip("Not Implemented")
+    def test_encode_offset_commit_request(self):
+        pass
+
+    @unittest.skip("Not Implemented")
+    def test_decode_offset_commit_response(self):
+        pass
+
+    @unittest.skip("Not Implemented")
+    def test_encode_offset_fetch_request(self):
+        pass
+
+    @unittest.skip("Not Implemented")
+    def test_decode_offset_fetch_response(self):
+        pass
 
 
 if __name__ == '__main__':