can you hear me now? tackling telephony testing

Can You Hear Me Now?

Tackling Testing TelephonyBen Klang

[email protected]

Friday, August 10, 12

mailto:[email protected]


How Telephony Testing Is Different



•Apps are long-running code




• Inputs may be more constrained (DTMF)





•Or they may be less constrained (IM, Voice)






•Lots of things are happening concurrently







•External call interactions (conf, barge)







•External call interactions (conf, barge)

•XMPP Events


How Telephony Testing Is Familiar



•Same Tooling: rspec, mocha, cucumber, factory_girl, guard, rcov, rake




•Still draw lines between M, V and C





•Good class design is important





•Good class design is important

• It’s Just Ruby


Philosophy: SRP


Philosophy: SRP

•Single Responsibility Principle


Philosophy: SRP


• If you need to use “and” to describe the purpose of a class, you are probably breaking this rule


Philosophy: SRP


• If you need to use “and” to describe the purpose of a class, you are probably breaking this rule

•SRP is key to making classes testable


SRP Example


SRP Example•Class purpose: “To schedule calls and to place them”



•Testing requires mocking methods within the same class



•Testing requires mocking methods within the same class

•Non-trivial work to swap calling mechanism


Philosophy: Tell, Don’t Ask



•Tell an object to do its work




•Don’t ask for its state then ask it to do something




•Don’t ask for its state then ask it to do something

•Works Hand-in-Hand with SRP


Philosophy: Prefer/Share Immutable



•Methods should only use passed-in data




•Avoid instance vars or other shared state





•Especially helpful with concurrent code





•Especially helpful with concurrent code

• ... but makes testing in general easier


Prefer/Share Immutable Example


Levels of Testing


Levels of Testing

Integration


Levels of Testing

Integration

Functional


Levels of Testing

Integration

Functional

Unit


Levels of Testing


Levels of Testing

• Integration Testing


Levels of Testing


•End-to-End


Levels of Testing


•End-to-End

•Provide predefined inputs


Levels of Testing


•End-to-End


•Verify outputs


Levels of Testing


•End-to-End


•Verify outputs

•Mock as little as possible


Integration Testing Tools for Telephony


Integration Testing Tools for Telephony• sipp:sipp.sourceforge.net



• Loadbot:github.com/mojolingo/ahn-loadbot



• Loadbot:github.com/mojolingo/ahn-loadbot

• Cucumber-VoIP:github.com/benlangfeld/cucumber-voip


Functional Testing


Functional Testing

•Test just one unit in isolation


Functional Testing


•Typical unit is a single class


Functional Testing


•Typical unit is a single class

•Test function of classbut do not makeassertions about internal state


Unit Testing


Unit Testing

•Most common form of testing


Unit Testing


•Test that a given unit (typically: method) behaves the way you expect


Unit Testing



•Make sure to test:


Unit Testing



•Make sure to test:•Valid inputs


Unit Testing



•Make sure to test:•Valid inputs• Invalid inputs


Unit Testing



•Make sure to test:•Valid inputs• Invalid inputs•Error Conditions


Unit Testing Example


Testing Concurrency


Testing Concurrency

•Design with a concurrency model or library


Testing Concurrency


•Celluloid, EventMachine


Testing Concurrency



•Use State Machines to guarantee sequence


Testing Concurrency




•Mock non-blocking dependent operations with blocking mocks


Testing Concurrency




•Mock non-blocking dependent operations with blocking mocks

•Always provide a timeout


Testing Concurrency

https://github.com/benlangfeld/countdownlatch




http://adhearsion.com/conference/2012




Can You Hear Me Now?

Tackling Testing Telephony Ben [email protected]@bklang Github/Twitterspkr8.com/t/12971

Thanks to Ben Langfeld for his assistance with this presentation@benlangfeld




http://spkr8.com/t/12971

http://spkr8.com/t/12971

can you hear me now? tackling telephony testing

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telephony testing

testing telephonyben

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prefershare immutable

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srp example class purpose