about approvaltests for better unit testing

An open source library for better Unit Testing

Woody Zuill & Lynn Langit

Agile 2012 – August 2012

Building your Testing ToolkitTest Runner

Nunit, MSTest, JUnit, XUnitCode

Asserts, otherLibraries

Approval TestsManual testsAutomated tests & tools

Differencing Tools

Approval Tests and Test Types

Using Unit Tests

• New Code - application code (components)• Testing APIs – functionality, edge cases• Legacy Code – locking tests• Learning new APIs – scope, functionality

Unit Testing Output?

• Granularity• Feedback• Specification• Regression

Why use ApprovalTests?

• Simple = easy to test = use Asserts– Ex. Verify a Scalar Value

• Complex = hard to test = use ApprovalTests– Ex. Verify Array Values– Ex. Verify a GUI– Ex. Verify a Database

query

DEMOGetting started

How Test-Driven

TDD• Assert• Do• Verify

BDD• Think Bigger• Less Code• Scenarios

ApprovalTests fit in with both types of testing

DEMOTesting Arrays

Testing Circle

About Reporters

• Reporters are DiffTools• ApprovalTests includes

support for many Reporters

• It’s simple to add hooks to your favorite diff tool

How to Approve

Contents provided are serialized to the file as binary (for comparison)• Rename *.received to *.approved• Right click ‘Approve’ (VS plug-in)• Right click ‘Use whole file’ (DiffReporter)• Copy ‘Move’ statement

from Test Results to command window

DEMOApproving GUIs

• HTML• Browser/text diff• ASP.NET• ASP.NET verify

Code must be Testable• Easy to write tests for it• Runnable tests must

exist– Write one test that

passes– Then write another test

on another method– Return to the first test

when needed

Peel and Slice Videos

• 3 videos in .NET (Mocks) series ‘peel, slice and peel and slice’

• Getting ready to use (data) Loaders

Testing Data Loading

• Mocks (fakes) data population• Tests the USE of data • Does not require a live connection to the

database• Thin layer (ILoader) which decouples data load• Unit Tests test without dependencies

Data Usage Patterns

Load

Save

Manipulate

Common Preferred

DEMOTesting calls to a Database

Integration Testing• Allows testing of functionality across multiple

objects (behavior or scenarios)• Example testing ASP.NET MVC – video here

Legacy Code

How much of your code base is dead code?

Locking Tests (Characterization Tests)

• Test to enable refactoring• Ensures system still works

the same• Most often used with

Legacy Code• Quickly results in high test

coverage

DEMOLegacy Code – Chart Smart

Visual Studio Code Coverage Config

Code CoverageHow much of your code base is covered?

Who wrote ApprovalTests?

Dan Gilkerson

LlewellynFalco

For More Information• www.ApprovalTests.com• Pick your language &

download• Pick your diff tool• Reference, Approve & Enjoy• Learn more – videos (.NET)• Podcast - HerdingCode

APPROVAL TESTSQ & A

@LynnLangit@WoodyZuill