Fundamental testing methodologies applied to the popular Python language Testing Python; Applying Unit Testing, TDD, BDD and Acceptance Testing is the most comprehensive book available on testing for one of the top software programming languages in the world. Python is a natural choice for new and experienced developers, and this hands-on resource is a much needed guide to enterprise-level testing development methodologies. The book will show you why Unit Testing and TDD can lead to cleaner, more flexible programs.
Unit Testing and Test-Driven Development (TDD) are increasingly must-have skills for software developers, no matter what language they work in. In enterprise settings, it's critical for developers to ensure they always have working code, and that's what makes testing methodologies so attractive. This book will teach you the most widely used testing strategies and will introduce to you to still others, covering performance testing, continuous testing, and more.
- Learn Unit Testing and TDD—important development methodologies that lie at the heart of Agile development
- Enhance your ability to work with Python to develop powerful, flexible applications with clean code
- Draw on the expertise of author David Sale, a leading UK developer and tech commentator
- Get ahead of the crowd by mastering the underappreciated world of Python testing
Knowledge of software testing in Python could set you apart from Python developers using outmoded methodologies. Python is a natural fit for TDD and Testing Python is a must-read text for anyone who wants to develop expertise in Python programming.
Table of Contents:
Introduction 1 CHAPTER 1 A History of Testing 5
You Do Test, Don’t You? 7
Fundamentals and Best Practices 7
Python Installation 8
Linux 8
Mac 8
Windows 8
Pip 9
Virtualenv 9
Source Control (SVN, Git) 10
Interactive Development Environment (IDE) 11
Summary 12
CHAPTER 2 Writing Unit Tests 15
What Is Unit Testing? 15
What Should You Test? 17
Writing Your First Unit Test 17
Checking Values with the assertEquals Method 18
Checking Exception Handling with assertRaises 20
Following the PEP-8 Standard 22
Unit Test Structure 23
Additional Unit Test Examples 24
Getting Clever with assertRaises 24
Making Your Life Easier with setUp 25
Useful Methods in Unit Testing 27
assertEqual(x, y, msg=None) 27
assertAlmostEqual(x, y, places=None, msg=None, delta=None) 27
assertRaises(exception, method, arguments, msg=None) 28
assertDictContainsSubset(expected, actual, msg=None) 28
assertDictEqual(d1, d2, msg=None) 28
assertTrue(expr, msg=None) 28
assertFalse(expr, msg=None) 29
assertGreater(a, b, msg=None) 29
assertGreaterEqual(a, b, msg=None) 29
assertIn(member, container, msg=None) 30
assertIs(expr1, expr2) 30
assertIsInstance(obj, class, msg=None) 30
assertNotIsInstance(obj, class, msg=None) 30
assertIsNone(obj, msg=None) 30
assertIsNot(expr1, expr2, msg=None) 31
assertIsNotNone(obj, msg=None) 31
assertLess(a, b, msg=None) 31
assertLessEqual(a, b, msg=None) 31
assertItemsEqual(a, b, msg=None) 31
assertRaises(excClass, callableObj, *args, **kwargs, msg=None) 32
Summary 32
CHAPTER 3 Utilizing Unit Test Tools 33
Using Python’s Nose 33
Installing Nose 34
Using Nose’s Best Features 35
Running Specifi c Test Files 35
Getting More Detail with Verbose 35
Debugging Support with PDB 36
Checking Your Coverage 38
Coloring your tests with Rednose 39
PyTest: An Alternative Test Runner 40
Installing PyTest 40
PyTest’s Best Features 41
Running Specifi c Tests 41
Viewing Detail with Verbose and Summary 42
Debugging with PDB 43
Checking Your Coverage with PyTest 45
Choosing Between Nose and PyTest 46
Mock and Patch Tricky Situations 46
Installing the Mock Library 47
Mocking a Class and Method Response 47
When Mock Won’t Do, Patch! 50
The Requests Library 50
Patch in Action 50
Advanced Mocking 52
Summary 53
CHAPTER 4 Writing Testable Documentation 55
Writing Your First Doctest 56
Th e Python Shell 56
Adding Doctests to a Method 57
Running Your Doctests 58
Handling Error Cases 59
Advanced Doctest Usage 61
Improving Doctests with Nose Integration 62
Summary 65
Resources 65
CHAPTER 5 Driving Your Development with Tests 67
Agile Development 67
Adopting the Agile Process Now 68
Ethos of Test Driven Development 70
Advantages of Test Driven Development 72
Ping-Pong Programming 72
Test Driving Your Problem 73
Writing Your Failing Test 74
Making Your Test Pass 75
Driving More Features with Tests 75
Wrapping Up the Task 77
Summary 82
Resources 83
CHAPTER 6 Writing Acceptance Tests 85
What Is Acceptance Testing? 85
Anatomy of an Acceptance Test 87
Using Gherkin Syntax 87
Th e Magic Is in the Step File 88
Goals of Acceptance Testing 89
Implementing Developer and QA Collaboration 90
Letting Behavior Drive Your Problem 90
Writing Your Failing Acceptance Test 90
Defining Your Steps 92
Implementing Your Code 94
Developing More of the Feature 95
bank_apppy 96
indexhtml 97
Delivering the Finished Article 98
Advanced Acceptance Test Techniques 102
Scenario Outline 102
Tables of Data in Scenarios 103
Summary 104
Resources 105
CHAPTER 7 Utilizing Acceptance Test Tools 107
Cucumber: The Acceptance Test Standard 107
Lettuce in Detail 108
Tagging 108
Fail Fast 112
Nosetest Integration 114
Robot: An Alternative Test Framework 115
Installing Robot 116
Writing a Test Case 116
Implementing Keywords 117
Running Robot Tests 119
Summary 123
Resources 123
CHAPTER 8 Maximizing Your Code’s Performance 125
Understanding the Importance of Performance Testing 126
JMeter and Python 126
Installation 127
Configuring Your Test Plans 128
Utilizing Your Test Plans Effectively 135
Code Profiling with cProfile 135
Run a cProfile Session 136
Analyzing the cProfile Output 142
Summary 144
Resources 144
CHAPTER 9 Looking After Your Lint 145
Coming to Grips with Pylint 146
Installing Pylint 146
Using Pylint 146
Understanding the Pylint Report 149
The Module Block 149
The Messages by Category Section 149
The Messages Section 150
The Code Evaluation Score 150
The Raw Metrics Section 150
The Statistics by Type Section 150
Customizing Pylint’s Output 150
Telling Pylint to Ignore Errors 153
Covering All Your Code with Unit Tests 154
Installing Coverage 155
Using Coverage 155
Advanced Coverage Options 157
Producing an HTML/XML Report 157
Setting a Minimum Coverage Threshold 159
Restricting Coverage to a Specific Package 159
Ignoring Coverage 160
Summary 161
Resources 162
CHAPTER 10 Automating Your Processes 163
Build Paver Tasks 164
Installing Paver 164
Creating a Paver Task 164
Executing Paver Tasks 165
Defi ning a Default Build 166
Setting Up Automated Builds 168
Installing Jenkins 169
Adding Coverage and PyLint Reports 175
Generating a PyLint Report 175
Generating a Coverage Report 176
Making Your Build Status Highly Visible 176
Summary 181
Resources 181
CHAPTER 11 Deploying Your Application 183
Deploying Your Application to Production 184
Creating a Deployable Artifact 185
Defining the Paver Tasks 185
Incorporating Packaging into the Build 187
Enabling Archiving on Jenkins 188
QA Environment 189
Implementing Stage and Production Environments 190
Implementing a Cloud Deployment 191
Creating a Heroku Account 192
Creating a Small Application 193
Setting up Git for Heroku 193
Deploying the Application to Heroku 194
Smoke Testing a Deployed Application 195
Example Application Stack 196
Smoke Test Scenarios 197
Implementing Smoke Tests 198
Summary 200
Resources 201
CHAPTER 12 The Future of Testing Python 203
Stub the Solution 203
Making Deployment Natural 205
Automating (Nearly) Everything 206
Working in Public 207
Collaborating on Step Definitions 208
Final Thoughts 209
Resources 210
Index 211
