Search icon Close icon
Search icon CANCEL
Subscription
0
Cart icon
Your Cart (0 item)
Close icon
You have no products in your basket yet
Save more on your purchases! discount-offer-chevron-icon
Savings automatically calculated. No voucher code required.
Checkout

Change country

Modal Close icon
Country selected Country selected
country flag United States
Country selected
country flag Great Britain
Country selected
country flag India
Country selected
country flag Germany
Country selected
country flag France
Country selected
country flag Canada
Country selected
country flag Russia
Country selected
country flag Spain
Country selected
country flag Brazil
Country selected
country flag Australia
Country selected
country flag Singapore
Country selected
country flag Canary Islands
Country selected
country flag Hungary
Country selected
country flag Ukraine
Country selected
country flag Luxembourg
Country selected
country flag Estonia
Country selected
country flag Lithuania
Country selected
country flag South Korea
Country selected
country flag Turkey
Country selected
country flag Switzerland
Country selected
country flag Colombia
Country selected
country flag Taiwan
Country selected
country flag Chile
Country selected
country flag Norway
Country selected
country flag Ecuador
Country selected
country flag Indonesia
Country selected
country flag New Zealand
Country selected
country flag Cyprus
Country selected
country flag Denmark
Country selected
country flag Finland
Country selected
country flag Poland
Country selected
country flag Malta
Country selected
country flag Czechia
Country selected
country flag Austria
Country selected
country flag Sweden
Country selected
country flag Italy
Country selected
country flag Egypt
Country selected
country flag Belgium
Country selected
country flag Portugal
Country selected
country flag Slovenia
Country selected
country flag Ireland
Country selected
country flag Romania
Country selected
country flag Greece
Country selected
country flag Argentina
Country selected
country flag Netherlands
Country selected
country flag Bulgaria
Country selected
country flag Latvia
Country selected
country flag South Africa
Country selected
country flag Malaysia
Country selected
country flag Japan
Country selected
country flag Slovakia
Country selected
country flag Philippines
Country selected
country flag Mexico
Country selected
country flag Thailand
Country selected
Arrow left icon
Explore Products
Best Sellers
New Releases
Books
Videos
Audiobooks
Learning Hub
Newsletter Hub
Free Learning
Arrow right icon
timer SALE ENDS IN
0 Days
:
00 Hours
:
00 Minutes
:
00 Seconds
Home > Web Development > Test Driven Development > Test Driven Python Development
Test Driven Python Development
Test Driven Python Development

Test Driven Python Development: Develop high-quality and maintainable Python applications using the principles of test-driven development

Arrow left icon
Profile Icon Siddharta Govindaraj
Arrow right icon
€41.99
Full star icon Full star icon Full star icon Full star icon Half star icon 4.4 (5 Ratings)
Paperback Apr 2015 264 pages 1st Edition
eBook
€28.99 €32.99
Paperback
€41.99
Subscription
Free Trial
Renews at €18.99p/m
Arrow left icon
Profile Icon Siddharta Govindaraj
Arrow right icon
€41.99
Full star icon Full star icon Full star icon Full star icon Half star icon 4.4 (5 Ratings)
Paperback Apr 2015 264 pages 1st Edition
eBook
€28.99 €32.99
Paperback
€41.99
Subscription
Free Trial
Renews at €18.99p/m
eBook
€28.99 €32.99
Paperback
€41.99
Subscription
Free Trial
Renews at €18.99p/m

What do you get with Print?

Product feature icon Instant access to your digital copy whilst your Print order is Shipped
Product feature icon Paperback book shipped to your preferred address
Product feature icon Redeem a companion digital copy on all Print orders
Product feature icon Access this title in our online reader with advanced features
Product feature icon DRM FREE - Read whenever, wherever and however you want
OR

Contact Details

Modal Close icon
Payment Processing...
tick Completed

Shipping Address

Billing Address

Shipping Methods
Table of content icon View table of contents Preview book icon Preview Book

Test Driven Python Development

Chapter 2. Red-Green-Refactor – The TDD Cycle

In the previous chapter, we went through a small TDD cycle by creating a failing test and then making it pass. In this chapter, we are going to fill out the rest of the Stock class by writing more tests. In the process, we will dig deeper into the TDD cycle and the unittest module.

Tests are executable requirements

In the first test, we wrote a very simple test that checked whether a new Stock class has its price attribute initialized to None. We can now think about what requirement we want to implement next.

An observant reader might have caught on to the terminology used in the previous sentence, where I said that we can think about the requirement to implement next, instead of saying that we can think about the test to write next. Both statements are equivalent, because in TDD, tests are nothing but requirements. Each time we write a test and implement code to make it pass, what we actually do is make the code meet some requirement. Looking at it another way, tests are just executable requirement specifications. Requirement documentation often goes out of sync with what is actually implemented, but this is impossible with tests, because the moment they go out of sync, the test will fail.

In the previous chapter, we said that the Stock class will be used to hold...

Arrange-Act-Assert

Let us start with the first requirement. Here is the test:

    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)

Here we call the update method (which doesn't exist yet) with the timestamp and price and then check that the price has been set correctly. We use the assertEqual method provided in the unittest.TestCase class to assert the value.

Since we are using the datetime module to set the timestamp, we will have to add the line from datetime import datetime to the top of the file before it will run.

This test follows the pattern of Arrange-Act-Assert.

  1. Arrange: Set up the context for the test. In this case, we create a Stock object. In other tests, it may involve creating multiple objects or...

Documenting our tests

When we run the tests, we get the following output:

.E
==================================================================
ERROR: test_stock_update (__main__.StockTest)
An update should set the price on the stock object
------------------------------------------------------------------
Traceback (most recent call last):
  File "stock_alerter\stock.py", line 22, in test_stock_update
    goog.update(datetime(2014, 2, 12), price=10)
AttributeError: 'Stock' object has no attribute 'update'

------------------------------------------------------------------
Ran 2 tests in 0.001s
FAILED (errors=1)

The test fails as expected, but the interesting thing is that the first line of the docstring is printed out on the fourth line. This is useful because we get some more information on which case is failing. This shows a second way of documenting out tests by using the first line for a short summary, and the rest of the docstring for a more detailed explanation...

Testing for exceptions

Another requirement is that the price should not be negative. We would want to raise a ValueError if the price is negative. How would we check for this expectation in a test? Here is one way to do that:

    def test_negative_price_should_throw_ValueError(self):
        goog = Stock("GOOG")
        try:
            goog.update(datetime(2014, 2, 13), -1)
        except ValueError:
            return
        self.fail("ValueError was not raised")

In the preceding code, we call the update method with a negative price. This call is wrapped with a try...except block to catch ValueError. If the exception is raised correctly, then control goes into the except block where we return from the test. Since the test method returned successfully, it is marked as passing. If the exception is not raised, then the fail method gets called. This is another method provided by unittest.TestCase and raises a test failure exception when it is called. We can pass in a message...

Exploring assert methods

Now we have just one requirement for update remaining:

  • -Done- It should take a timestamp and price value and set it on the object
  • -Done- The price cannot be negative
  • After multiple updates, the object gives us the latest price

Let us take the remaining requirement. Here is the test:

    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)

What this test does is to simply call update twice, and when we ask for the price, provide us with the newer one. The interesting point about the test is that we use the assertAlmostEqual method here. This method is often used when checking equality with floating point numbers. Why don't we use plain old assertEqual? The reason is that due to the way floating points are stored, the result may not be exactly the number you...

Tests are executable requirements

In the first test, we wrote a very simple test that checked whether a new Stock class has its price attribute initialized to None. We can now think about what requirement we want to implement next.

An observant reader might have caught on to the terminology used in the previous sentence, where I said that we can think about the requirement to implement next, instead of saying that we can think about the test to write next. Both statements are equivalent, because in TDD, tests are nothing but requirements. Each time we write a test and implement code to make it pass, what we actually do is make the code meet some requirement. Looking at it another way, tests are just executable requirement specifications. Requirement documentation often goes out of sync with what is actually implemented, but this is impossible with tests, because the moment they go out of sync, the test will fail.

In the previous chapter, we said that the Stock class will be used to hold price...

Arrange-Act-Assert

Let us start with the first requirement. Here is the test:

    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)

Here we call the update method (which doesn't exist yet) with the timestamp and price and then check that the price has been set correctly. We use the assertEqual method provided in the unittest.TestCase class to assert the value.

Since we are using the datetime module to set the timestamp, we will have to add the line from datetime import datetime to the top of the file before it will run.

This test follows the pattern of Arrange-Act-Assert.

  1. Arrange: Set up the context for the test. In this case, we create a Stock object. In other tests, it may involve creating multiple objects or hooking a few things together that will be required...

Documenting our tests

When we run the tests, we get the following output:

.E
==================================================================
ERROR: test_stock_update (__main__.StockTest)
An update should set the price on the stock object
------------------------------------------------------------------
Traceback (most recent call last):
  File "stock_alerter\stock.py", line 22, in test_stock_update
    goog.update(datetime(2014, 2, 12), price=10)
AttributeError: 'Stock' object has no attribute 'update'

------------------------------------------------------------------
Ran 2 tests in 0.001s
FAILED (errors=1)

The test fails as expected, but the interesting thing is that the first line of the docstring is printed out on the fourth line. This is useful because we get some more information on which case is failing. This shows a second way of documenting out tests by using the first line for a short summary, and the rest of the docstring for a more detailed explanation. The detailed explanation...

Testing for exceptions

Another requirement is that the price should not be negative. We would want to raise a ValueError if the price is negative. How would we check for this expectation in a test? Here is one way to do that:

    def test_negative_price_should_throw_ValueError(self):
        goog = Stock("GOOG")
        try:
            goog.update(datetime(2014, 2, 13), -1)
        except ValueError:
            return
        self.fail("ValueError was not raised")

In the preceding code, we call the update method with a negative price. This call is wrapped with a try...except block to catch ValueError. If the exception is raised correctly, then control goes into the except block where we return from the test. Since the test method returned successfully, it is marked as passing. If the exception is not raised, then the fail method gets called. This is another method provided by unittest.TestCase and raises a test failure exception when it is called. We can pass in a message to provide some...

Exploring assert methods

Now we have just one requirement for update remaining:

  • -Done- It should take a timestamp and price value and set it on the object

  • -Done- The price cannot be negative

  • After multiple updates, the object gives us the latest price

Let us take the remaining requirement. Here is the test:

    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)

What this test does is to simply call update twice, and when we ask for the price, provide us with the newer one. The interesting point about the test is that we use the assertAlmostEqual method here. This method is often used when checking equality with floating point numbers. Why don't we use plain old assertEqual? The reason is that due to the way floating points are stored, the result may not be exactly the number you expect. There...

Specific asserts versus generic asserts

One question that might come to your mind is why there are so many different assert methods. Why can't we just use assertTrue instead of the more specific assert, as shown in the following code:

assertInSeq(x, seq)
assertTrue(x in seq)

assertEqual(10, x)
assertTrue(x == 10)

While they are certainly equivalent, one motivation for using a specific assert is that you get a better error message if the assertion fails. When comparing objects like lists and dicts, the error message will show exactly where the difference occurs, making it much easier to understand. Therefore, it is recommended to use the more specific asserts wherever possible.

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")
        self.assertIsNone(stock.price)

    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...

Brittle tests

We've implemented the three requirements for the update method:

  • -Done- It should take a timestamp and price value and set it on the object

  • -Done- After multiple updates, the object gives us the latest price

  • -Done- The price cannot be negative

Now, let us suppose that a new requirement comes up that we had not known about before:

  • The Stock class needs a method to check if the stock has an increasing trend. An increasing trend is one where each of the latest three updates is an increase over the previous one.

So far, our Stock implementation just stores the latest price. In order to implement this functionality, we need to store some history of past price values. One way to do this is to change the price variable to a list. The problem is that when we change the internals of our implementation, it would break all of our tests, because all of them access the price variable directly and assert that it has specific values.

What we see here is an example of test brittleness.

A test is...

Left arrow icon

Page 1 of 14

Right arrow icon

Key benefits

  • Write robust and easily maintainable code using the principles of test driven development
  • Get solutions to real-world problems faced by Python developers
  • Go from a unit testing beginner to a master through a series of step-by-step tutorials that are easy to follow

Description

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.

Who is this book for?

This book is intended for Python developers who want to use the principles of test-driven development (TDD) to create efficient and robust applications. In order to get the best out of this book, you should have development experience with Python.

What you will learn

  • Implement the test-driven development process in Python applications
  • Fully leverage Python s powerful built-in unittest and doctest modules
  • Effectively add features to existing code bases that do not have any tests
  • Safely resolve problems with the code and design, without breaking any functionality
  • Utilize Python s powerful mock and patch functionality to test complex interactions
  • Integrate unit testing into the overall software delivery process
  • Use doctest to test code with examples
  • Enhance TDD with the nose2 test runner
Estimated delivery fee Deliver to Greece

Premium delivery 7 - 10 business days

€17.95
(Includes tracking information)

Product Details

Country selected
Publication date, Length, Edition, Language, ISBN-13
Publication date : Apr 29, 2015
Length: 264 pages
Edition : 1st
Language : English
ISBN-13 : 9781783987924
Category :
Web Development
Languages :
Python
Concepts :
Test Driven Development
Tools :
Nose

What do you get with Print?

Product feature icon Instant access to your digital copy whilst your Print order is Shipped
Product feature icon Paperback book shipped to your preferred address
Product feature icon Redeem a companion digital copy on all Print orders
Product feature icon Access this title in our online reader with advanced features
Product feature icon DRM FREE - Read whenever, wherever and however you want
OR

Contact Details

Modal Close icon
Payment Processing...
tick Completed

Shipping Address

Billing Address

Shipping Methods
Estimated delivery fee Deliver to Greece

Premium delivery 7 - 10 business days

€17.95
(Includes tracking information)

Product Details

Publication date : Apr 29, 2015
Length: 264 pages
Edition : 1st
Language : English
ISBN-13 : 9781783987924
Category :
Web Development
Languages :
Python
Concepts :
Test Driven Development
Tools :
Nose

Packt Subscriptions

See our plans and pricing
Modal Close icon
€18.99 billed monthly
Feature tick icon Unlimited access to Packt's library of 7,000+ practical books and videos
Feature tick icon Constantly refreshed with 50+ new titles a month
Feature tick icon Exclusive Early access to books as they're written
Feature tick icon Solve problems while you work with advanced search and reference features
Feature tick icon Offline reading on the mobile app
Feature tick icon Simple pricing, no contract
START FREE TRIAL
BUY NOW
€189.99 billed annually
Feature tick icon Unlimited access to Packt's library of 7,000+ practical books and videos
Feature tick icon Constantly refreshed with 50+ new titles a month
Feature tick icon Exclusive Early access to books as they're written
Feature tick icon Solve problems while you work with advanced search and reference features
Feature tick icon Offline reading on the mobile app
Feature tick icon Choose a DRM-free eBook or Video every month to keep
Feature tick icon PLUS own as many other DRM-free eBooks or Videos as you like for just €5 each
Feature tick icon Exclusive print discounts
START FREE TRIAL
BUY NOW
€264.99 billed in 18 months
Feature tick icon Unlimited access to Packt's library of 7,000+ practical books and videos
Feature tick icon Constantly refreshed with 50+ new titles a month
Feature tick icon Exclusive Early access to books as they're written
Feature tick icon Solve problems while you work with advanced search and reference features
Feature tick icon Offline reading on the mobile app
Feature tick icon Choose a DRM-free eBook or Video every month to keep
Feature tick icon PLUS own as many other DRM-free eBooks or Videos as you like for just €5 each
Feature tick icon Exclusive print discounts
START FREE TRIAL
BUY NOW

Frequently bought together

Functional Python Programming
Functional Python Programming
Read more
Jan 2015 360 pages
Full star icon 4 (9)
eBook
eBook
  • eBook eBook €28.99
  • Paperback Paperback €41.99
€28.99 €32.99
€41.99
Test Driven Python Development
Test Driven Python Development
Read more
Apr 2015 264 pages
Full star icon 4.4 (5)
eBook
eBook
  • eBook eBook €28.99
  • Paperback Paperback €41.99
€28.99 €32.99
€41.99
Python 3 Object-Oriented Programming - Second Edition
Python 3 Object-Oriented Programming - Second Edition
Read more
Aug 2015 460 pages
Full star icon 3.9 (36)
eBook
eBook
  • eBook eBook €28.99
  • Paperback Paperback €41.99
€28.99 €32.99
€41.99
Stars icon
Total € 125.97
Functional Python Programming
€41.99
Test Driven Python Development
€41.99
Python 3 Object-Oriented Programming - Second Edition
€41.99
Total € 125.97 Stars icon

Table of Contents

13 Chapters
1. Getting Started with Test-Driven Development Chevron down icon Chevron up icon
1. Getting Started with Test-Driven Development
Prerequisites
Understanding test-driven development
Using TDD to build a stock alert application
Reorganizing the test code
Summary
2. Red-Green-Refactor – The TDD Cycle Chevron down icon Chevron up icon
2. Red-Green-Refactor – The TDD Cycle
Tests are executable requirements
Arrange-Act-Assert
Documenting our tests
Testing for exceptions
Exploring assert methods
Specific asserts versus generic asserts
Setup and teardown
Brittle tests
Refactoring the design
Refactoring tests
Exploring the Rule classes
Exercise
Summary
3. Code Smells and Refactoring Chevron down icon Chevron up icon
3. Code Smells and Refactoring
A dual crossover moving average
Implementing the dual crossover moving average
Identifying code smells
Refactoring
The importance of tests
Exercise
Wrapping up
Summary
4. Using Mock Objects to Test Interactions Chevron down icon Chevron up icon
4. Using Mock Objects to Test Interactions
Hand writing a simple mock
Using the Python mocking framework
Tying it all together
Summary
5. Working with Legacy Code Chevron down icon Chevron up icon
5. Working with Legacy Code
What is legacy code?
Understanding the code
Techniques to break dependencies
The cycle continues
Time to refactor
Summary
6. Maintaining Your Test Suite Chevron down icon Chevron up icon
6. Maintaining Your Test Suite
Goals of test maintenance
Organizing tests
Making tests readable
Writing tests closer to the domain
Summary
7. Executable Documentation with doctest Chevron down icon Chevron up icon
7. Executable Documentation with doctest
Our first doctest
Test failures
Testing for exceptions
Package-level doctests
Maintaining doctests
Limitations of doctest
How do doctests fit into the TDD process?
Summary
8. Extending unittest with nose2 Chevron down icon Chevron up icon
8. Extending unittest with nose2
Getting started with nose2
Writing tests for nose2
nose2 plugins
Summary
9. Unit Testing Patterns Chevron down icon Chevron up icon
9. Unit Testing Patterns
Pattern – fast tests
Pattern – running a subset of tests
Pattern – using attributes
Pattern – expected failures
Pattern – data-driven tests
Pattern – integration and system tests
Pattern – spies
Summary
10. Tools to Improve Test-Driven Development Chevron down icon Chevron up icon
10. Tools to Improve Test-Driven Development
TDD tools
Integrating with build tools
Integrating with packaging tools
Distutils
Integrating with continuous integration tools
Other tools
IDE integration
Summary
A. Answers to Exercises Chevron down icon Chevron up icon
A. Answers to Exercises
Red-Green-Refactor – The TDD Cycle
Code Smells and Refactoring
B. Working with Older Python Versions Chevron down icon Chevron up icon
B. Working with Older Python Versions
Writing code that is compatible across versions
Running tests from the command line
Running the examples in this book
Index Chevron down icon Chevron up icon
Index

Recommendations for you

Left arrow icon
Full-Stack Flask and React
Full-Stack Flask and React
Read more
Oct 2023 408 pages
Full star icon 3.8 (5)
eBook
eBook
  • eBook eBook €20.99
  • Paperback Paperback €29.99
€20.99 €23.99
€29.99
C# 13 and .NET 9 – Modern Cross-Platform Development Fundamentals
C# 13 and .NET 9 – Modern Cross-Platform Development Fundamentals
Read more
Nov 2024 828 pages
Full star icon 4.4 (5)
eBook
eBook
  • eBook eBook €26.98
  • Paperback Paperback €37.99
€26.98 €29.99
€37.99
Real-World Web Development with .NET 9
Real-World Web Development with .NET 9
Read more
Dec 2024 578 pages
Full star icon 3.5 (4)
eBook
eBook
  • eBook eBook €26.98
  • Paperback Paperback €37.99
€26.98 €29.99
€37.99
Django 5 By Example
Django 5 By Example
Read more
Apr 2024 820 pages
Full star icon 4.6 (40)
eBook
eBook
  • eBook eBook €26.98
  • Paperback Paperback €37.99
€26.98 €29.99
€37.99
React and React Native
React and React Native
Read more
Apr 2024 518 pages
Full star icon 4.3 (10)
eBook
eBook
  • eBook eBook €23.99
  • Paperback Paperback €32.99
€23.99 €26.99
€32.99
Scalable Application Development with NestJS
Scalable Application Development with NestJS
Read more
Jan 2025 612 pages
Full star icon 4.5 (6)
eBook
eBook
  • eBook eBook €20.99
  • Paperback Paperback €29.99
€20.99 €23.99
€29.99
C# 12 and .NET 8 – Modern Cross-Platform Development Fundamentals
C# 12 and .NET 8 – Modern Cross-Platform Development Fundamentals
Read more
Nov 2023 828 pages
Full star icon 4.4 (74)
eBook
eBook
  • eBook eBook €31.99
  • Paperback Paperback €44.99
€31.99 €35.99
€44.99
Responsive Web Design with HTML5 and CSS
Responsive Web Design with HTML5 and CSS
Read more
Sep 2022 504 pages
Full star icon 4.5 (57)
eBook
eBook
  • eBook eBook €23.99
  • Paperback Paperback €33.99
€23.99 €26.99
€33.99
Modern Full-Stack React Projects
Modern Full-Stack React Projects
Read more
Jun 2024 506 pages
Full star icon 4.8 (9)
eBook
eBook
  • eBook eBook €23.99
  • Paperback Paperback €33.99
€23.99 €26.99
€33.99
Learning Angular
Learning Angular
Read more
Jan 2025 494 pages
Full star icon 4 (6)
eBook
eBook
  • eBook eBook €23.99
  • Paperback Paperback €33.99
€23.99 €26.99
€33.99
Right arrow icon

Customer reviews

Rating distribution
Full star icon Full star icon Full star icon Full star icon Half star icon 4.4
(5 Ratings)
5 star 60%
4 star 20%
3 star 20%
2 star 0%
1 star 0%
Miguel Rentes Jun 01, 2015
Full star icon Full star icon Full star icon Full star icon Full star icon 5
This book provides an excellent learning artifact and reference to the Test-Driven Development practice. Even if you have already used TDD in your software projects or continue to use it, you will benefit a lot of reading this book, because it will show you how to take the most out of using TDD with Python's unittest built-in module in a simple software application to follow. The book is also very easy and accessible to read. It makes the reader acknowledge all the power of TDD and the tools the author uses to extend the TDD practice is a value asset to use on any software project.Why this is a great book to me:- The TDD approach is carefully explained and the importance of using it in our software projects;- The software application the author uses as an example on how to use TDD is simple to understand, and it is a real world software application, not an abstract example; We go carefully into every module of this application while improving our application with TDD;- This book covers Refactoring Patterns and Anti-Patterns and how to avoid recurrent Code Smells;- Explains how to use Mock Objects to test interactions between multiple objects;- Tells us how to deal with legacy code which have no tests. This is a must-read chapter!- Shows us how to maintain our test suite with docstrings, custom test class hierarchies, fixtures, helper methods, custom assert matches, equality functions and matchers to make our code more readable;- Covers executable documentation with Python's doctest module, on methods, classes, modules and packages;- Shows us how to extend Python's unittest with nose2, a powerful third-party tool and plugin suite;- Covers Unit Test Patterns, from Mocking Patterns, Spies, Generator functions, to Mocking with Mutable Arguments;- A rich set of powerful tools is gathered in this book: from third-party tools and Python's built-in modules, build tools, packaging tools, continuous integration tools, documentation tools and current TDD IDE integration;- Python 3.4 throughout this book, although the author has compiled an annex on how to use the code samples in Python 2.6 as well.Overall, this is a great book to read and to use in every software development process. After reading this book I can't think of any reason why any software projects shouldn't have tests anymore, and shouldn't be continuous integrated as well. This book shows exactly how to achieve the best out of the TDD approach with the current tools in Python 3. It's well worth a read and to have at hand, no doubt.
Amazon Verified review Amazon
Sergio Mar 09, 2017
Full star icon Full star icon Full star icon Full star icon Full star icon 5
Great book walking you through abstract TTD concepts with Python. Would love to see some examples in different production environments and maybe a chapter on how to do this in large scale production environments.
Amazon Verified review Amazon
tb May 01, 2019
Full star icon Full star icon Full star icon Full star icon Full star icon 5
If I can save dollars by purchasing from a reseller, and I do not need the book immediately, I will. The book arrived as described!
Amazon Verified review Amazon
Jacob Zimmerman Jun 01, 2015
Full star icon Full star icon Full star icon Full star icon Empty star icon 4
Cons:- Kindle format text is WAY too big (at least on my device) - they're looking into getting this fixed if they can- Packt Publishing didn't do the best job with editing. There are quite a few (not a LOT, but enough to be a bit annoying) mistakes of all kinds. Missing words, code mistakes, typos, etc.- A TDD book that only starts off showing TDD, then mostly doesn't show tests until after showing the code.Pros:+ Great at introducing TDD and unit testing in python, then really digging into the more advanced stuff.+ First thing I've found that explains Python's built-in mocking framework very well.+ Doesn't repeat too much and doesn't move too quicklyNote: Only 3 or 4 (out of 10) chapters are truly about TDD as opposed to just unit testing. It's up to you whether this is good or bad.
Amazon Verified review Amazon
tony Jul 27, 2015
Full star icon Full star icon Full star icon Empty star icon Empty star icon 3
I was really excited to review this book. I've already read the Django TDD book by Henry Percival and covered the Testing Python book by David Sale, they were both really informative and covered TDD principles and tools in a manner I found clear and easy to understand. That being said, this book started to lose me around the 3rd chapter. Here's my analysis:Pros:-The author covers a lot of really good topics related to TDD. Code smells, refactoring, how to address a pre-existing code base that you're walking into for the first time were all topics I found to be really helpful.-The book challenged me to learn about Python topics that I had not previously known about. I wasn't sure how @classmethod worked or what the setUpClass method did in unittesting, but I certainly looked them up when the book presented them to me and was sure to fully understand them before proceeding.-The code coverage is available on GitHub, which is always great, so you can follow along easily.Cons:-I felt like the organization of the book started to slack around the 2nd chapter in Exploring the Rule classes. The whole point of TDD is for the programmer to write the tests first and the implementation code 2nd. We make the tests fail, we write code until it passes, we move on. Then we refactor. Great. Why, in the 2nd chapter, are we then presented with implementation code (no tests), then a discussion of TDD principles, followed by "here's the tests and they should pass".-Further to this point, it started to get difficult to read in chapter 3 which begins discussion of a new functionality, dual crossover moving average. Immediately, we get the implementation code (again, no tests) followed by a discussion about renaming variable and renaming method refactoring methods, both of which involve running the tests first to make sure they pass. When it comes time to implement this code, the author simply says "the tests are in the exercise section". So I'm supposed to read up to that point, then skip to the end to check out the exercises and get the tests, then go back and continue working on the code base? Furthermore, I am looking at the exercises as I type this and there is no presentation of those tests whatsoever.-Finally, while the book does cover some good topics, there are times when it gets a little off topic (I guess). For instance, in the section regarding commenting styles, we begin discussion about how to properly write comments (of course). However, rather than applying this to the current code base and application we are working on, the author gives an example of determining if people are old enough to receive a senior citizen discount. I know this is a simple example, but why switch gears when we could have easily applied this to what was being worked on (there was a presentation of a very poorly written method at the beginning of the chapter). All in all, I wouldn't say this was a poor book, I've read some O'Reilly work that could make you want to quit programming altogether, but I do think there could be some effective revisions to make it easier to read and understand. I have a lot of respect for authors who decide to take on TDD as it is a discipline and requires constant effort and attention. That being said, I would recommend this book to review the principles and topics discussed, but not necessarily to follow along in a step by step manner.
Amazon Verified review Amazon

People who bought this also bought

Left arrow icon
C# 11 and .NET 7 – Modern Cross-Platform Development Fundamentals
C# 11 and .NET 7 – Modern Cross-Platform Development Fundamentals
Read more
Nov 2022 818 pages
Full star icon 4.1 (54)
eBook
eBook
  • eBook eBook €26.98
  • Paperback Paperback €37.99
€26.98 €29.99
€37.99
C# 12 and .NET 8 – Modern Cross-Platform Development Fundamentals
C# 12 and .NET 8 – Modern Cross-Platform Development Fundamentals
Read more
Nov 2023 828 pages
Full star icon 4.4 (74)
eBook
eBook
  • eBook eBook €31.99
  • Paperback Paperback €44.99
€31.99 €35.99
€44.99
Responsive Web Design with HTML5 and CSS
Responsive Web Design with HTML5 and CSS
Read more
Sep 2022 504 pages
Full star icon 4.5 (57)
eBook
eBook
  • eBook eBook €23.99
  • Paperback Paperback €33.99
€23.99 €26.99
€33.99
React and React Native
React and React Native
Read more
May 2022 606 pages
Full star icon 4.6 (17)
eBook
eBook
  • eBook eBook €26.98
  • Paperback Paperback €37.99
€26.98 €29.99
€37.99
Building Python Microservices with FastAPI
Building Python Microservices with FastAPI
Read more
Aug 2022 420 pages
Full star icon 3.9 (9)
eBook
eBook
  • eBook eBook €25.99
  • Paperback Paperback €35.99
€25.99 €28.99
€35.99
Right arrow icon

About the author

Profile icon Siddharta Govindaraj
Siddharta Govindaraj
Siddharta Govindaraj first encountered Python in 2002, and it has remained his favorite programming language ever since. He was an early participant in BangPypers, India's first Python community, and a speaker at InPycon. He is the founder of Silver Stripe Software, an Indian product start-up that develops products based on Python. A vocal proponent of the language, Siddharta extols the virtues of Python to anyone who will listenand also to those who won't. His blog is at http://www.siddharta.me.
Read more
See other products by Siddharta Govindaraj
Get free access to Packt library with over 7500+ books and video courses for 7 days!
Start Free Trial

FAQs

What is the digital copy I get with my Print order? Chevron down icon Chevron up icon

When you buy any Print edition of our Books, you can redeem (for free) the eBook edition of the Print Book you’ve purchased. This gives you instant access to your book when you make an order via PDF, EPUB or our online Reader experience.

What is the delivery time and cost of print book? Chevron down icon Chevron up icon

Shipping Details

USA:

'

Economy: Delivery to most addresses in the US within 10-15 business days

Premium: Trackable Delivery to most addresses in the US within 3-8 business days

UK:

Economy: Delivery to most addresses in the U.K. within 7-9 business days.
Shipments are not trackable

Premium: Trackable delivery to most addresses in the U.K. within 3-4 business days!
Add one extra business day for deliveries to Northern Ireland and Scottish Highlands and islands

EU:

Premium: Trackable delivery to most EU destinations within 4-9 business days.

Australia:

Economy: Can deliver to P. O. Boxes and private residences.
Trackable service with delivery to addresses in Australia only.
Delivery time ranges from 7-9 business days for VIC and 8-10 business days for Interstate metro
Delivery time is up to 15 business days for remote areas of WA, NT & QLD.

Premium: Delivery to addresses in Australia only
Trackable delivery to most P. O. Boxes and private residences in Australia within 4-5 days based on the distance to a destination following dispatch.

India:

Premium: Delivery to most Indian addresses within 5-6 business days

Rest of the World:

Premium: Countries in the American continent: Trackable delivery to most countries within 4-7 business days

Asia:

Premium: Delivery to most Asian addresses within 5-9 business days

Disclaimer:
All orders received before 5 PM U.K time would start printing from the next business day. So the estimated delivery times start from the next day as well. Orders received after 5 PM U.K time (in our internal systems) on a business day or anytime on the weekend will begin printing the second to next business day. For example, an order placed at 11 AM today will begin printing tomorrow, whereas an order placed at 9 PM tonight will begin printing the day after tomorrow.


Unfortunately, due to several restrictions, we are unable to ship to the following countries:

  1. Afghanistan
  2. American Samoa
  3. Belarus
  4. Brunei Darussalam
  5. Central African Republic
  6. The Democratic Republic of Congo
  7. Eritrea
  8. Guinea-bissau
  9. Iran
  10. Lebanon
  11. Libiya Arab Jamahriya
  12. Somalia
  13. Sudan
  14. Russian Federation
  15. Syrian Arab Republic
  16. Ukraine
  17. Venezuela
What is custom duty/charge? Chevron down icon Chevron up icon

Customs duty are charges levied on goods when they cross international borders. It is a tax that is imposed on imported goods. These duties are charged by special authorities and bodies created by local governments and are meant to protect local industries, economies, and businesses.

Do I have to pay customs charges for the print book order? Chevron down icon Chevron up icon

The orders shipped to the countries that are listed under EU27 will not bear custom charges. They are paid by Packt as part of the order.

List of EU27 countries: www.gov.uk/eu-eea:

A custom duty or localized taxes may be applicable on the shipment and would be charged by the recipient country outside of the EU27 which should be paid by the customer and these duties are not included in the shipping charges been charged on the order.

How do I know my custom duty charges? Chevron down icon Chevron up icon

The amount of duty payable varies greatly depending on the imported goods, the country of origin and several other factors like the total invoice amount or dimensions like weight, and other such criteria applicable in your country.

For example:

  • If you live in Mexico, and the declared value of your ordered items is over $ 50, for you to receive a package, you will have to pay additional import tax of 19% which will be $ 9.50 to the courier service.
  • Whereas if you live in Turkey, and the declared value of your ordered items is over € 22, for you to receive a package, you will have to pay additional import tax of 18% which will be € 3.96 to the courier service.
How can I cancel my order? Chevron down icon Chevron up icon

Cancellation Policy for Published Printed Books:

You can cancel any order within 1 hour of placing the order. Simply contact customercare@packt.com with your order details or payment transaction id. If your order has already started the shipment process, we will do our best to stop it. However, if it is already on the way to you then when you receive it, you can contact us at customercare@packt.com using the returns and refund process.

Please understand that Packt Publishing cannot provide refunds or cancel any order except for the cases described in our Return Policy (i.e. Packt Publishing agrees to replace your printed book because it arrives damaged or material defect in book), Packt Publishing will not accept returns.

What is your returns and refunds policy? Chevron down icon Chevron up icon

Return Policy:

We want you to be happy with your purchase from Packtpub.com. We will not hassle you with returning print books to us. If the print book you receive from us is incorrect, damaged, doesn't work or is unacceptably late, please contact Customer Relations Team on customercare@packt.com with the order number and issue details as explained below:

  1. If you ordered (eBook, Video or Print Book) incorrectly or accidentally, please contact Customer Relations Team on customercare@packt.com within one hour of placing the order and we will replace/refund you the item cost.
  2. Sadly, if your eBook or Video file is faulty or a fault occurs during the eBook or Video being made available to you, i.e. during download then you should contact Customer Relations Team within 14 days of purchase on customercare@packt.com who will be able to resolve this issue for you.
  3. You will have a choice of replacement or refund of the problem items.(damaged, defective or incorrect)
  4. Once Customer Care Team confirms that you will be refunded, you should receive the refund within 10 to 12 working days.
  5. If you are only requesting a refund of one book from a multiple order, then we will refund you the appropriate single item.
  6. Where the items were shipped under a free shipping offer, there will be no shipping costs to refund.

On the off chance your printed book arrives damaged, with book material defect, contact our Customer Relation Team on customercare@packt.com within 14 days of receipt of the book with appropriate evidence of damage and we will work with you to secure a replacement copy, if necessary. Please note that each printed book you order from us is individually made by Packt's professional book-printing partner which is on a print-on-demand basis.

What tax is charged? Chevron down icon Chevron up icon

Currently, no tax is charged on the purchase of any print book (subject to change based on the laws and regulations). A localized VAT fee is charged only to our European and UK customers on eBooks, Video and subscriptions that they buy. GST is charged to Indian customers for eBooks and video purchases.

What payment methods can I use? Chevron down icon Chevron up icon

You can pay with the following card types:

  1. Visa Debit
  2. Visa Credit
  3. MasterCard
  4. PayPal
What is the delivery time and cost of print books? Chevron down icon Chevron up icon

Shipping Details

USA:

'

Economy: Delivery to most addresses in the US within 10-15 business days

Premium: Trackable Delivery to most addresses in the US within 3-8 business days

UK:

Economy: Delivery to most addresses in the U.K. within 7-9 business days.
Shipments are not trackable

Premium: Trackable delivery to most addresses in the U.K. within 3-4 business days!
Add one extra business day for deliveries to Northern Ireland and Scottish Highlands and islands

EU:

Premium: Trackable delivery to most EU destinations within 4-9 business days.

Australia:

Economy: Can deliver to P. O. Boxes and private residences.
Trackable service with delivery to addresses in Australia only.
Delivery time ranges from 7-9 business days for VIC and 8-10 business days for Interstate metro
Delivery time is up to 15 business days for remote areas of WA, NT & QLD.

Premium: Delivery to addresses in Australia only
Trackable delivery to most P. O. Boxes and private residences in Australia within 4-5 days based on the distance to a destination following dispatch.

India:

Premium: Delivery to most Indian addresses within 5-6 business days

Rest of the World:

Premium: Countries in the American continent: Trackable delivery to most countries within 4-7 business days

Asia:

Premium: Delivery to most Asian addresses within 5-9 business days

Disclaimer:
All orders received before 5 PM U.K time would start printing from the next business day. So the estimated delivery times start from the next day as well. Orders received after 5 PM U.K time (in our internal systems) on a business day or anytime on the weekend will begin printing the second to next business day. For example, an order placed at 11 AM today will begin printing tomorrow, whereas an order placed at 9 PM tonight will begin printing the day after tomorrow.


Unfortunately, due to several restrictions, we are unable to ship to the following countries:

  1. Afghanistan
  2. American Samoa
  3. Belarus
  4. Brunei Darussalam
  5. Central African Republic
  6. The Democratic Republic of Congo
  7. Eritrea
  8. Guinea-bissau
  9. Iran
  10. Lebanon
  11. Libiya Arab Jamahriya
  12. Somalia
  13. Sudan
  14. Russian Federation
  15. Syrian Arab Republic
  16. Ukraine
  17. Venezuela