Avoid test failures, and document the bug in Docker Desktop for Windows that was causing them.

Author: arpost

README.rst

@@ -76,7 +76,9 @@ We recommend you use a `virtual environment <https://virtualenv.pypa.io/en/stabl
 
 Note, the anonymous tier of Docker Hub rate limits downloads to 100 container image requests per six hours, and running all of the tests in the tests directory for the first time appears to exceed the limit.
 
-Also, the SQL Server tests will fail unless you have Microsoft ODBC Driver 17 for SQL Server installed, available from https://docs.microsoft.com/en-us/sql/connect/odbc/download-odbc-driver-for-sql-server.
+The SQL Server tests will fail unless you have Microsoft ODBC Driver 17 for SQL Server installed, available from https://docs.microsoft.com/en-us/sql/connect/odbc/download-odbc-driver-for-sql-server.
+
+There is an apparent bug in Docker Desktop for Windows, described at https://github.com/docker/docker-py/issues/2792, that causes the DockerContainer.getExposedPort() method to fail if it is called immediately after starting the container. Some of the test cases implement a 5 second time timeout to avoid hitting this bug.
 
 Adding requirements
 ^^^^^^^^^^^^^^^^^^^

tests/test_db_containers.py

@@ -130,7 +130,7 @@ def test_docker_run_neo4j_latest():
 
 def test_docker_generic_db():
     mongo_container = DockerContainer("mongo:latest")
-    mongo_container.with_bind_ports(27017, 27017)
+    mongo_container.with_exposed_ports(27017)
 
     with mongo_container:
         def connect():

tests/test_kafka.py

@@ -2,14 +2,18 @@
 
 from testcontainers.kafka import KafkaContainer
 
+import time
+
 
 def test_kafka_producer_consumer():
     with KafkaContainer() as container:
+        time.sleep(5)
         produce_and_consume_kafka_message(container)
 
 
 def test_kafka_producer_consumer_custom_port():
     with KafkaContainer(port_to_expose=9888) as container:
+        time.sleep(5)
         assert container.port_to_expose == 9888
         produce_and_consume_kafka_message(container)
 

tests/test_new_docker_api.py

@@ -1,6 +1,7 @@
 import os
 import re
 from pathlib import Path
+import time
 
 from testcontainers import mysql
 
@@ -19,6 +20,7 @@ def test_docker_custom_image():
     container.with_env("MYSQL_ROOT_PASSWORD", "root")
 
     with container:
+        time.sleep(5)
         port = container.get_exposed_port(3306)
         assert int(port) > 0
 

tests/test_nginx_container.py

@@ -7,10 +7,10 @@
 def test_docker_run_nginx():
     nginx_container = NginxContainer("nginx:1.13.8")
     with nginx_container as nginx:
+        time.sleep(5)
         port = nginx.port_to_expose
         url = "http://{}:{}/".format(nginx.get_container_host_ip(),
                                      nginx.get_exposed_port(port))
-        time.sleep(5)
         r = requests.get(url)
         assert(r.status_code == 200)
         assert('Welcome to nginx!' in r.text)