Initial commit

Author: flosommerfeld

.env

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+export FLASK_APP=app
+export FLASK_ENV=development
+PYTHONPATH=${PYTHONPATH}:src

Makefile

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+###################################################################################
+# This Makefile is used for installing dependencies, running the dev server and   #
+# running tests.                                                                  #
+###################################################################################
+
+# Run 'make help' if there is no specified target. -> i.e. 'make'
+.DEFAULT_GOAL := help
+
+# Print a small manual on how this Makefile can be used
+help:
+	@echo "usage:"
+	@echo "   make <target>"
+	@echo "targets:"
+	@echo "   install        Install project dependencies and git pre-commit hooks"
+	@echo "   run            Run development server at http://localhost:5000"
+	@echo "   test           Run all available tests of the project"
+	@echo "   help           List usage and available targets"
+
+# Installs project dependencies and git pre-commit hooks.
+install:
+	pipenv install
+
+# Runs the development server which will be served at http://localhost:5001
+run:
+	pipenv run flask run
+
+# Runs all tests of the project
+test:
+	pipenv run pytest --cov=src --cov-report=html --cov-report=term --cov-branch test/

Pipfile

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+[[source]]
+url = "https://pypi.org/simple"
+verify_ssl = true
+name = "pypi"
+
+[packages]
+flask = "*"
+flask-sqlalchemy = "*"
+pytest = "*"
+pytest-mock = "*"
+
+[dev-packages]
+
+[requires]
+python_version = "3.9"

Pipfile.lock

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+class Config(object):
+    DEBUG = False
+    TESTING = False
+    SQLALCHEMY_DATABASE_URI = "sqlite:///:memory:"
+
+class ProductionConfig(Config):
+    SQLALCHEMY_DATABASE_URI = 'mysql://user@localhost/foo'
+
+class DevelopmentConfig(Config):
+    DEBUG = True
+
+class TestingConfig(Config):
+    TESTING = True
+    SQLALCHEMY_TRACK_MODIFICATIONS = False

config.py

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+import os
+from flask import Flask, jsonify
+from flask_sqlalchemy import SQLAlchemy
+from sqlalchemy.dialects.postgresql import VARCHAR
+
+basedir = os.path.abspath(os.path.dirname(__file__))
+
+
+app = Flask(__name__) # instantiate app
+app.config.from_object("config.TestingConfig") # load testing config from config.py
+db = SQLAlchemy() # instantiate sqlalchemy
+db.init_app(app) # link sqlalchemy to app
+
+# Example for a database model
+class MyModel(db.Model):
+    id = db.Column("id", VARCHAR, primary_key=True, unique=True, nullable=False)
+
+# Example route
+@app.route("/", methods=['GET'])
+def get_value():
+    mod = MyModel.query.first()
+    return jsonify(mod.id), 200

src/__init__.py

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+import pytest
+from flask import Flask
+from flask_sqlalchemy import SQLAlchemy
+from src.app import MyModel
+
+
+@pytest.fixture
+def mock_my_model():
+    """ 
+    This fixture mocks the database model 'MyModel' which will have the id 'my_mock_id'. 
+    This id can be used in the test cases.
+    """
+    my_model = MyModel(
+        id="my_mock_id",
+    )
+    return my_model
+
+
+@pytest.fixture
+def mock_get_sqlalchemy(mocker):
+    """ This fixture will mock the SQLAlchemy query response from the database """
+    mock = mocker.patch(
+        "flask_sqlalchemy._QueryProperty.__get__").return_value = mocker.Mock()
+    return mock
+
+
+@pytest.fixture
+def flask_app_mock():
+    """ Flask application mock set up. """
+    app_mock = Flask(__name__)
+    db = SQLAlchemy(app_mock)
+    db.init_app(app_mock)
+    return app_mock

src/app.py

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+from src.app import get_value
+
+
+def test_get_value(flask_app_mock, mock_my_model, mock_get_sqlalchemy):
+    """ This test will call the function under test (get_value()) and succeeds if
+    get_value() returns the ID of MyModel which shall be 'my_mock_id'."""
+    mock_get_sqlalchemy.first.return_value = mock_my_model
+
+    with flask_app_mock.app_context():
+        response = get_value() # call the function under test
+
+    # check if we've gotten our mocked model object
+    assert response[0].json == "my_mock_id"