the path to unit testing

The Path to Unit Testing

Contact Information

Wes McClure

wes.mcclure@gmail.com

wmcclure@phxwg.com

@g0t4

Poll – How do you test?

Manual Testing Automated Testing QA? Deploy and unplug the phone!

Agenda

Before Testing Unit Testing Frameworks Dependencies Legacy Testing Good Testing

Before Testing

Scenario

Weather on company portal. NOAA web service Input zip code Get latitude / longitude Show weather forecast

Where to start?

Build a Prototype? Console app

Move into web app

Ok Done!

What is done? Hanselminutes #119

Tested?

 Time Detected

Requirements

Architecture

Construction

System Test

Post-Release

Time Introduced

Requirements 1× 3× 5–10× 10× 10–100×Architecture - 1× 10× 15× 25–100×Construction - - 1× 10× 10–25×

It was tested … manually How?

Run program Provide input Execute action Subjectively verify output

Problems with Manual

Thrown away In the noggin

Not documented Easily forgotten

Documented Refactorability

Easy paths 1 bug fixed = 2 new

How can I fix this?

Automate

Unit Testing

Definition (wikipedia) Is a software verification and validation

method in which a programmer tests if individual units of source code are fit for use. A unit is the smallest testable part of an application. … in object-oriented programming, the smallest unit is a class…

Testing the smallest piece

Unit Test Composition

AAA Arrange (Given) Act (When) Assert (Then)

Same as manual template

States

Passing Failing Not Run

Questions?

Before Testing

Unit Testing Frameworks

Test Discovery

Inheritance Naming ConvetionsAttributes

NUnit Test Discovery

Basic Attributes TestFixture Test Ignore Category

Test Execution

Exectuion Selection Run Results (State)

Types Console GUI IDE Integrated

NUnit Test Execution

Runners Console GUI MiniGUI

IDE Integrated TestDriven.Net R# Test Runner Gallio

Assertions

Classic Fluent

“Fluent is the new xml”

NUnit Assertion Syntax

Classic Assertions Fluent Constraints AssertionHelper

Expect Constraints

Is Has Throws

Putting it all together

Hello World Test

More NUnit Attributes

SetUp & TearDown

Per Test Once for Test Fixture Once for Namespace

Cautious

Parameterized Tests

TestCase Result TestName

Theory DataPoint

Caution

Attributes to Avoid

Random Tests should be repeatable!

Sequential Tests shouldn’t be interdependent!

Repeat Win the lottery?

Other attributes Localization

Culture SetCulture

Labeling Description Suite Property

Parametric Attributes▪ Values▪ ValueSource▪ Range

Combinatorial Pairwise TestCaseSource

Timing (async) MaxTime Timeout

Threading RequiresMTA RequiresSTA RequiresThread

Others Explicit RequiredAddIn Suite ExpectedException Platform

Questions?

Unit Testing Frameworks (with NUnit)

Dependenciesanother word for "testable" is "decoupled"

Dependencies

Weather Dependencies

Input to SUT Acted upon

Unit Testing with Dependencies Unit Testing => Isolated Unit Stubs

Simulate Dependencies Return Dummy Data

Mocks Record Calls

Manual Stubs & Mocks

Roll our own

Cons Low reuse Boilerplate Complex

logic

Poll

Who has used an isolation framework?

Isolation Frameworks

Dynamic stubs Proxies Setup results

Dynamic mocks Record calls Verification syntax

Example

Isolation Frameworks

Rhino.Mocks TypeMock Moq NMock2

Questions?

Legacy Testing

Define Legacy

Old Untested – Michael Feathers Missing seams

Why Change Legacy Code? Fix Bugs

Repeats Add Features

Integrated Isolated

Improve Design 80/20

Improve Moral

Fixing Bugs

Example

Legacy Testing@martinfowler

@ JoshuaKerievsky

Questions?

Legacy Testing

Good Unit Tests

But…

Anything can be done but it takes effort to do it well!

Consistency in choices Best PracticesTry alternatives

Good Unit Tests

From “The Art of Unit Testing” Readable Maintainable Trustworthy

For us and others

@RoyOsherovehttp://www.artofunittesting.com/http://weblogs.asp.net/ROsherove/

Readability

Naming Convention Method_Scenario_Expectation Explicit Variables

▪ Call stubs & mocks as such! Fluent Assertions

var

Readability

AAA Physical Separate

Readability

Single Assertion SRP methods

Transfer? Credit Debit Insufficient funds Transactional Success / Failure Auditing

Readability - Organized

Separate Tests project. Per app or project

1+ TestFixture Per class

1+ Test Per method

Maintainable

Fast Automated Zero Configuration IDE Integration Continuous Integration

DRY Factories

Independent

Trustworthy

RepeatableRetainedVersionedConfident

Resources

Uncle Bob Martin @unclebobmartin butunclebob.com

Podcasts (search for terms in archives) Hanselminutes▪ 169 - Roy Osherove▪ 119 – Unit Test Frameworks

DotNetRocks Test_Review_Guidelines (The Art of Unit

Testing)

Questions?

Good Unit Tests