This repository is originally one of the labs for the NYU DevOps class for Spring 2017, CSCI-GA.3033-013 on Behavior Driven Development with Flask and Behave

The sample code is using Flask microframework and is intented to test the Python support on IBM Cloud environment which is based on Cloud Foundry. It also uses CouchDB as a database for storing JSON objects.

One of my favorite quotes is:

“If it's worth building, it's worth testing. If it's not worth testing, why are you wasting your time working on it?”

As Software Engineers we need to have the discipline to ensure that our code works as expected and continues to do so regardless of any changes, refactoring, or the introduction of new functionality.

This lab introduces Test Driven Development using PyUnit and nose. It also explores the use of using RSpec syntax with Python through the introduction of noseOfYeti and expects as plug-ins that make test cases more readable.

It also introduces Behavior Driven Development using Behave as a way to define Acceptance Tests that customer can understand and developers can execute!

For easy setup, you need to have Vagrant and VirtualBox installed. Then all you have to do is clone this repo and invoke vagrant:

    git clone https://github.com/nyu-devops/lab-flask-bdd.git
    cd lab-flask-bdd
    vagrant up && vagrant ssh
    cd /vagrant

You can now run behave and nosetests to run the BDD and TDD tests respectively.

These tests require the service to be running becasue unlike the the TDD unit tests that test the code locally, these BDD intagration tests are using Selenium to manipulate a web page on a running server.

Run the tests using behave

    $ honcho start &
    $ behave

Note that the & runs the server in the background. To stop the server, you must bring it to the foreground and then press Ctrl+C

Stop the server with

    $ fg
    $ <Ctrl+C>

Alternately you can run the server in another shell by opening another terminal window and using vagrant ssh to establish a second connection to the VM. You can also suppress all log output in the current shell with this command:

    honcho start 2>&1 > /dev/null &

or you can supress info logging with this command:

    gunicorn --bind 0.0.0.0 --log-level=error service:app &

This will suppress the normal INFO logging

This repo also has unit tests that you can run nose

    $ nosetests

Nose is configured to automatically include the flags --with-spec --spec-color so that red-green-refactor is meaningful. If you are in a command shell that supports colors, passing tests will be green while failing tests will be red.

* ./service/service.py -- the main Service using Python Flask
* ./service/models.py -- the data models for persistence
* ./tests/test_service.py -- unit test cases for the server
* ./tests/test_pets.py -- unit test cases for the model
* ./features/pets.feature -- Behave feature file
* ./features/steps/steps.py -- Behave step definitions

If you want to deploy this example in a Docker container, you can run the tests from the container.

This service requires CouchDB so first start a CouchDB Docker container

    docker run -d --name couchdb -p 5984:5984 -e COUCHDB_USER=admin -e COUCHDB_PASSWORD=pass couchdb

Docker Note: CouchDB uses /opt/couchdb/data to store its data, and is exposed as a volume e.g., to use current folder add: -v $(pwd):/opt/couchdb/data You can also use Docker volumes like this: -v couchdb:/opt/couchdb/data

Next build this repo as a container

    docker build -t flask-bdd .

This will build a Docker image with the name flask-bdd

To run nosetests just run it in a container while linking it to the couchdb container that we have running by adding --link couchdb and CLOUDANT_HOST=couchdb like this.

    docker run --rm --link couchdb -e CLOUDANT_HOST=couchdb flask-bdd nosetests

The --link couchdb inserts the IP address of the counchdb container into the /etc/hosts file and then defining the environment variable CLOUDANT_HOST=couchdb tells our models.py file to use that as the name of the database server.

To run behave tests we need an instance of our service running so it takes two docker commands, one to run our service and another to run the behave tests

    docker run -d --name flask-service --link couchdb -p 5000:5000 -e CLOUDANT_HOST=couchdb flask-bdd
    docker run --rm --link flask-service -e BASE_URL="http://flask-service:5000/" flask-bdd behave

Notice how we injected the URL of the running service into our container that is running the behave tests using an environment variable BASE_URL in keeping with 12-factor pratice "III. Config: Store config in the environment" which recommends the passing of configuraition parameters as environment variables.

When you are finished exploring this lab, you can bring down these services using:

    docker stop flask-bdd
    docker stop couchdb

...and to remove them with:

    docker rm flask-bdd
    docker rm couchdb

This repository is part of the NYU class CSCI-GA.2810-001: DevOps and Agile Methodologies taught by John Rofrano, Adjunct Instructor, NYU Curant Institute, Graduate Division, Computer Science.