The Pester Book: The All-in-One Guide to Understanding and Writing Tests for PowerShell

About the Author
Foreword
Feedback
Code Samples
Introduction
	Testing as Institutional Memory
	Testing Drives Better Modularization
	Tests as Functional Specifications
	Tests in Automated Build Pipelines
	Where We’re Not Going
	Resources
Part I - Pester Concepts
Block Introduction
	Describe Blocks
	Context Blocks
	It Blocks
	Before and After Blocks
	Summary
TestDrive and TestRegistry
	Using TestDrive
	Using TestRegistry
	Summary
Assertions
	Using the Should Assertion
	Understanding Should Operators
	Testing Collections
	Other Tests
	Testing Errors
	Adding Custom Assertion Operators
	Because
	Summary
Test Cases
	Creating Tests for Different Parameters
	Using the TestCases Parameter
	Using the Test Name Token
	Summary
Mocking Introduction
	Mock Walkthrough
	Mock Assertions
	Summary
Code Coverage
	Why Code Coverage?
	Using Pester to Measure Code Coverage
	Getting Granular with Code Coverage
	Summary
Gherkin
	Files
	Features
	Scenarios
	Steps
	Step Definitions
	Running Gherkin Tests
	Summary
Part 2: Using Pester
Controlling Test Results
	Pending and Skipped States
	Forcing Pass/Fail States
	Summary
Working with Pester Output
	nUnit XML
	Returning Failed Tests as Exit Codes
	Summary
Tagging
	Introduction to Tagging
	Tagging Strategies
	Summary
Modules and Dot-Sourced Script Gotchas
	Scripts with Functions
	Modules
	Summary
Advanced Mocking
	Mocking Specific Object Types
	Mock Scope
	Module-Level Mocks
	Parameter Filters
	Summary
Mocking the Unmockable
	.NET Methods
	Creating Wrapper Functions
	“Overwriting” .NET Methods with a ScriptMethod
	Using “Stubbed” Commands
	Asserting Mocks “Transitively”
	Summary
Improving Code Coverage
	Step #1: Getting a Baseline
	Step #2: Build the Test Framework
	Step #3: Create the Mocks
	Step #4: Know the “Before” Code Coverage
	Step #5: Build all Tests
	Step #6: Re-check Code Coverage
	Summary
Infrastructure Testing
	Analyzing the Code
	Getting Testing Dependencies in Place
	Prototyping the Infrastructure Tests
	Assessing the Current Environment
	Writing the Infrastructure Tests
	Dependencies
	Operational Validation Framework (OVF)
	Summary
Troubleshooting and Debugging
	Sending Variables to the Console with Write-Host
	Using Debugger Breakpoints During Tests
	Summary
Test Walkthrough #1
	Analyzing the Code
	Refactoring
	Deciding What to Test
	Find the Shortest Code Path
	Creating Test(s) for the Shortest Code Path
	Building Tests for Other Code Paths
	Summary
Test Walkthrough #2
	Understand the Subject
	Designing Tests
	Writing the Tests
	ImportVariables Parameter
	ImportModules Parameter
	RunspaceTimeout Parameter
	Parameter parameter
	Summary
Part 3: Hands-On Design and Testing
Buildling Testable Code
	Modularization
	Limit Function Input
	Input Via Parameters
	Managing Output Properly
	Summary
Test Design Practices
	Ensuring Code “State” Doesn’t Change
	The Input/Execution/Output Pattern
	Choosing When to Create Describe Blocks
	Naming Conventions
	Summary
Part 4: Pester Cookbook
Recipe: Testing for Live Conditions
Recipe: Testing for Installed Software
Recipe: Ensuring all Functions in a Module Have Tests
Recipe: Testing External Applications
	The Background
	Testing Exit Codes from Standalone EXE files
Recipe: Testing Syntax
Recipe: Testing Remote Script Blocks
Resources
	Video Courses
	Articles