Book Image

Test-Driven Python Development

By : Siddharta Govindaraj
Book Image

Test-Driven Python Development

By: Siddharta Govindaraj

Overview of this book

This book starts with a look at the test-driven development process, and how it is different from the traditional way of writing code. All the concepts are presented in the context of a real application that is developed in a step-by-step manner over the course of the book. While exploring the common types of smelly code, we will go back into our example project and clean up the smells that we find. Additionally, we will use mocking to implement the parts of our example project that depend on other systems. Towards the end of the book, we'll take a look at the most common patterns and anti-patterns associated with test-driven development, including integration of test results into the development process.
Table of Contents (20 chapters)
Test-Driven Python Development
About the Author
About the Reviewers

Setup and teardown

Let us take a look at the tests that we have done so far:

    def test_price_of_a_new_stock_class_should_be_None(self):
        stock = Stock("GOOG")

    def test_stock_update(self):
        """An update should set the price on the stock object
        We will be using the `datetime` module for the timestamp
        goog = Stock("GOOG")
        goog.update(datetime(2014, 2, 12), price=10)
        self.assertEqual(10, goog.price)

    def test_negative_price_should_throw_ValueError(self):
        goog = Stock("GOOG")
        with self.assertRaises(ValueError):
            goog.update(datetime(2014, 2, 13), -1)

    def test_stock_price_should_give_the_latest_price(self):
        goog = Stock("GOOG")
        goog.update(datetime(2014, 2, 12), price=10)
        goog.update(datetime(2014, 2, 13), price=8.4)
        self.assertAlmostEqual(8.4, goog.price, delta=0.0001)

If you notice, each test does the same setup by instantiating...