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
Credits
About the Author
Acknowledgments
About the Reviewers
www.PacktPub.com
Preface
Index

Writing tests closer to the domain


The other way to make tests easier to read is to write tests in terms of the domain language instead of just the generic functions provided by unittest. In this section, we look at some ways to do this.

Writing helper methods

The first technique is to write helper methods. We employed this technique earlier in this book. The following are some tests that don't use a helper method:

    def test_increasing_trend_is_false_if_price_decreases(self):
        timestamps = [datetime(2014, 2, 11), datetime(2014, 2, 12),
                      datetime(2014, 2, 13)]
        prices = [8, 12, 10]
        for timestamp, price in zip(timestamps, prices):
            self.goog.update(timestamp, price)
        self.assertFalse(self.goog.is_increasing_trend())

    def test_increasing_trend_is_false_if_price_equal(self):
        timestamps = [datetime(2014, 2, 11), datetime(2014, 2, 12),
                      datetime(2014, 2, 13)]
        prices = [8, 10, 10]
        for timestamp...