tescontainers-python POC

The aim of this project is to POC the use of testcontainers-python for integration testing python code. The project aims to demonstrate the following:

1. Integration of testcontainers-python with behave (or similar python Cucumber port).
2. The spinning up of a generic container - running RabbitMQ in this case.
3. Waiting for the application running in the container to finish initializing.
4. Interacting with the application running inside the test container.

Running

To run the project code and the associated integration tests, initialize a virtual environment.

$ python3 -m venv ./.venv && source .venv/bin/activate && pip install -r requirements.txt
(.venv) $

It is assumed that docker will have been installed and is running on the machine being used.

simple_http_server.py

simple_http_server.py is the simple application that is being tested. It is a very simple web server that returns 'Hello, world!' in response to GET requests and adds the contents of the request body to RabbitMQ when a POST request is received.

To manually test the application, spin up a docker container running RabbitMQ:

$ docker run -d --hostname my-rabbit -p 15672:15672 -p 5672:5672 --name some-rabbit rabbitmq:3.8.3-management

Run the simple web server specifying the http port to listen for requests on and the rabbit port to send messages on:

$ source .venv/bin/activate
(.venv) $ python3 simple_http_server.py 8082 5672

Interact with the web server using cURL:

$ curl http://localhost:8082
  Hello, world!
$
$ curl -v http://localhost:8082 -d'[{"hello":"world"}]'
  *   Trying ::1...
  * TCP_NODELAY set
  * Connection failed
  * connect to ::1 port 8082 failed: Connection refused
  *   Trying 127.0.0.1...
  * TCP_NODELAY set
  * Connected to localhost (127.0.0.1) port 8082 (#0)
  > POST / HTTP/1.1
  > Host: localhost:8082
  > User-Agent: curl/7.64.1
  > Accept: */*
  > Content-Length: 19
  > Content-Type: application/x-www-form-urlencoded
  > 
  * upload completely sent off: 19 out of 19 bytes
  * HTTP 1.0, assume close after body
  < HTTP/1.0 201 Created
  < Server: BaseHTTP/0.6 Python/3.7.7
  < Date: Fri, 27 Mar 2020 13:33:16 GMT
  < 
  * Closing connection 0
$

Browse to http://localhost:15672/#/queues/%2F/test_queue using the credentials guest:guest to view the queue and see the 'hello world' message added to the queue.

Running the integration tests

To run the integration tests making use of testcontainers-python, activate the virtual environment and run behave:

$ source .venv/bin/activate
(.venv) $ behave

Pulling image rabbitmq:3.8.3-management
⠇
Container started:  00c3b92042
Feature: Testcontainers POC: demonstrates use of Testcontainers for integration testing # features/everything.feature:1

  Scenario: When a GET request is made to the simple webserver, a successful 'Hello World' response is returned  # features/everything.feature:3
    When a GET request is made to the simple webserver                                                           # features/steps/steps.py:12 0.004s
    Then the webserver will respond with a HTTP status of "200"                                                  # features/steps/steps.py:27 0.000s
    And the response body will contain "Hello, world!"                                                           # features/steps/steps.py:32 0.000s

  Scenario: When a POST request is made to the simple webserve, the request body is added to the RabbitMQ queue  # features/everything.feature:8
    When a POST request is made to the simple webserver                                                          # features/steps/steps.py:17 0.033s
    Then the webserver will respond with a HTTP status of "201"                                                  # features/steps/steps.py:27 0.000s
    And the response body will be empty                                                                          # features/steps/steps.py:37 0.000s
    And the request body is added to the RabbitMQ queue                                                          # features/steps/steps.py:42 0.027s

1 feature passed, 0 failed, 0 skipped
2 scenarios passed, 0 failed, 0 skipped
7 steps passed, 0 failed, 0 skipped, 0 undefined
Took 0m0.065s
(.venv) $