Fix: IoT does not work in server mode (#3644)

Closes #1631

tests/test_iotdata/test_server.py

@@ -1,5 +1,8 @@
 from __future__ import unicode_literals
 
+from six.moves.urllib.parse import quote
+
+import pytest
 import sure  # noqa
 
 import moto.server as server
@@ -19,3 +22,22 @@ def test_iotdata_list():
     thing_name = "nothing"
     res = test_client.get("/things/{}/shadow".format(thing_name))
     res.status_code.should.equal(404)
+
+
+@pytest.mark.parametrize(
+    "url_encode_topic",
+    [
+        pytest.param(True, id="Topic in Path is URL encoded"),
+        pytest.param(False, id="Topic in Path is *not* URL encoded"),
+    ],
+)
+@mock_iotdata
+def test_publish(url_encode_topic):
+    backend = server.create_backend_app("iot-data")
+    test_client = backend.test_client()
+
+    topic = "test/topic"
+    topic_for_path = quote(topic, safe="") if url_encode_topic else topic
+
+    result = test_client.post("/topics/{}".format(topic_for_path))
+    result.status_code.should.equal(200)