app/
    static/
    templates/
    forms.py
    models.py
    views.py
migrations/
config.py
manage.py
tests.py

# tests.py
import unittest
from app import create_app, db
from flask import current_app
class TestCase(unittest.TestCase):
    def setUp(self):
        self.app = create_app('test_config')
        self.app_context = self.app.app_context()
        self.app_context.push()
        db.create_all()
        self.client = self.app.test_client()
    def tearDown(self):
        db.session.remove()
        db.drop_all()
        self.app_context.pop()
    def test_app_exists(self):
        self.assertFalse(current_app is None)
    def test_hello(self):
        response = self.client.get('/')
        self.assertEqual(response.status_code, 200)

# config.py
class Config(object):
    SECRET_KEY = os.environ.get('COURSES_PROJECT_SECRET_KEY')
    SQL_COMMIT_ON_TEARDOWN = True
 
    @staticmethod
    def init_app(app):
        pass
class DevConfig(Config):
    DEBUG = True
    SQLALCHEMY_DATABASE_URI = os.environ.get('COURSES_PROJECT_DATABASE')
class TestingConfig(Config):
    TESTING = True
    SQLALCHEMY_DATABASE_URI = os.environ.get('TEST_COURSES_PROJECT_DATABASE')
    CSRF_ENABLED = False
config = {'default': DevConfig,
          'dev_config': DevConfig,
          'test_config': TestingConfig}

# app/__init__.py
from flask import Flask
from flask.ext.sqlalchemy import SQLAlchemy
from config import config
db = SQLAlchemy()
def create_app(config_name):
    app = Flask(__name__)
    app.config.from_object(config[config_name])
    db.init_app(app)
    return app
app = create_app('default')
from . import views