Improve tests.

 - Docstrings for AMQP tests.
 - Skip curl tests if pycurl is unavailable.
 - Time the AMQP test in case this is what is causing Travis to hang.

test/amqp_test.py

+"""Tests for ``pulsar.client.amqp_exchange``."""
 import time
 import threading
 
-from .test_utils import skip_unless_module
 from pulsar.client import amqp_exchange
 
+from .test_utils import (
+    skip_unless_module,
+    timed,
+)
+
 TEST_CONNECTION = "memory://test_amqp"
 
 
 @skip_unless_module("kombu")
+@timed(15)
 def test_amqp():
+    """Test the client PulsarExchange abstraction with an in-memory connection."""
     manager1_exchange = amqp_exchange.PulsarExchange(TEST_CONNECTION, "manager_test")
     manager3_exchange = amqp_exchange.PulsarExchange(TEST_CONNECTION, "manager3_test")
     manager2_exchange = amqp_exchange.PulsarExchange(TEST_CONNECTION, "manager2_test")
@@ -56,3 +63,6 @@ class TestThread(threading.Thread):
             raise AssertionError(msg)
 
         self.join(2)
+
+
+__all__ = ["test_amqp"]

test/client_transport_test.py

 import os
+from tempfile import NamedTemporaryFile
 
 from pulsar.client.transport.standard import Urllib2Transport
 from pulsar.client.transport.curl import PycurlTransport
 from pulsar.client.transport.curl import post_file
 from pulsar.client.transport.curl import get_file
 from pulsar.client.transport import get_transport
-from tempfile import NamedTemporaryFile
+
 from .test_utils import files_server
+from .test_utils import skip_unless_module
 
 
 def test_urllib_transports():
     _test_transport(Urllib2Transport())
 
 
+@skip_unless_module("pycurl")
 def test_pycurl_transport():
     _test_transport(PycurlTransport())
 
@@ -37,6 +40,7 @@ def _test_transport(transport):
         assert open(output_path, 'r').read().find("Test123") >= 0
 
 
+@skip_unless_module("pycurl")
 def test_curl_put_get():
     with files_server() as (server, directory):
         server_url = server.application_url
@@ -74,6 +78,7 @@ def test_curl_status_code():
         assert exception_raised
 
 
+@skip_unless_module("pycurl")
 def test_curl_problems():
     with files_server() as (server, directory):
         server_url = server.application_url