Testing for 'Net Developers

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Testing for .Net Developers

• By Paul Lockwood

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Brief Bio

• Coding is a hobby of 24 years
• Taken three CompSci Degrees
• First Consulting Gig in 1993
• 100 Development Focused
• There is still so much to learn!

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Aims for Today

• Awareness of Formality Extremes
• Project-to-project is very different
• Awareness of Testing Best Practices
• Basic understanding of AUT Testing
• Testing Buzzwords/ Products

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Methodologies

• Waterfall
• RUP (Rational Unified Process)
• Spiral/ Iterative Waterfalls
• MSFCMMI (Formal)
• MSFAgile
• Scrum
• Extreme Programming
• Code-and-Fix

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- The bottom line

• Dont forget Quality!

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Testing Techniques

• Write a test plan (89)
• V-Model (93)
• Record Your Tests (96)
• AUT - ASP.Net with MVC (02)
• AUT - TCP/IP (04)
• AUT - Data Processing (03/06)

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Write a Test Plan I - Requirements
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Write a Test Plan II The Plan
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Write a Test Plan - III

• 1989 - UK Ministry of Defence
• Cost Plus Pricing
• One Test Set could take over a week
• Pros
• Simplicity. Users can be trained to test
• Can test anything with a script
• Easy to tweak the plan while testing
• Cons
• How long will regression testing take?
• Code is generally throw over a large fence i.e.
  this is an expensive procedure fraught with
  politics

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A stitch in time saves nine
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V-Model Test plans refined

• 1993 - London Stock Exchange
• Andersen Consulting
• High . Testing is essential given nature of
  the business (13M over budget in sequence 2)
• Manually compared EDI logs
• Attention to detail necessary
• Cabinets full of regression test results
• In 2006 the better solution is obvious

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The V Model

• Old, but still in use today

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Record Your Tests (Scripts) I
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Record Your Tests (Scripts) II

• 1996 Yellow Pages
• Hundreds of GUI Screens with constant Maintenance
  and no time for regression tests
• Automated Testing Appears
• Cyrano Robot, SQL Robot, Rational Robot
• Mercury WinRunner
• Pros
• Automated replaying of testing
• Cons
• Need a developer to maintain tests
• Tests are Fragile
• Need to baseline database before testing

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AUT JUnit, NUnit, VS2K5

• 2002 - ASP.Net Project
• Post .bomb years so BCA
• NUnit Mandated on Project
• Only I used it
• Only I had zero defects
• Demo of AUT

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Testing in VS2K5

• Part of Team Suite
• 4K(?) per seat
• Use Test Driven.Net for free AUT
• Test Tools in Team System (developers)
• Unit Testing
• Code Coverage
• Static Analysis
• Code Profiling
• Test Tools in Team System (testers)
• Load Testing
• Web Testing
• Also Reporting (via Sharepoint too?)

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AUT - Very Involved GUI

• 2004 GUI Test Tool
• NUnit tested the Test Tool
• PInvokes
• Interaction with another application
• Move click the mouse
• Tricky threading issues
• Hard to reproduce Singleton defect
• NUnit kept me on the deadline

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AUT - Data in, Data Out

• 2003 NC DOT
• 2006 Healthcare Project
• Black Box Testing
• Embed Data In
• Embed Expected Data Out
• And Simply Compare!
• Datasets save as xml
• Unique Keys zap with RegExpressions
• Embedded Resource

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White Box vs Black Box Testing I

• Black Public API
• White Knowledge of internals

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White Box vs Black Box Testing II

• Tester Terminology
• Black As a user would
• White As a developer would
• Grey Access to config files
• Developer Terminology
• Black Public API
• White Low level methods etc
• VS 2005 can test Private members!
• Auto-gens a proxy class

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Test Driven Development

• 1. Analysis/ Light Design
• 2. Write tests
• 3. Code
• 4. Test
• 5. Refactor

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Refactoring

• Improve the Design of Existing Code
• Red, Green, Refactor
• Bad Smells
• Duplicated Code
• Long Method
• Shotgun Surgery
• Large Class
• Lazy Class
• Switch Statements

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Continuous Integration

• Testing Nirvana
• Auto build and test
• HanselMinutes.com show 5
• http//www.hanselminutes.com/default.aspx?showID5
  
• Team System Policies
• Unit Test before check-in

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AUT Pros and Cons

• The Good
• Errors spotted Early
• Much more testing will happen
• Takes minutes to test if you support a new
  Service Pack, Database, OS etc
• The Bad
• Extra Work (20-50) Can double development time
• Rework of tests if requirements change
• The Ugly
• Management/ Developer buy in
• Tests can become un-maintainable

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Final Slide

• Paul Lockwood
• dotnetchap_at_hotmail.com
• www.dotnetworkaholic.com

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History of xUnit

• Smalltalk Test Harnesses
• Smalltalk yet again!
• JUnit
• Kent Becks work
• Refactoring
• MEME reaching the masses now
• Can Refactor Mercilessly with xUnit
• XP and Agile Development
• Test Driven Development (TDD)
• Starts becoming High Church
• Scares many managers

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Did you say Free?

• Open Source zlib/libpng license
• Authors just want credit
• Java Community driven
• Proven concept
• JUnit, Ant, log4java, Hibernate, Eclipse
• Microsoft Endorsed
• Often in MSDN Magazine
• VS Team System 2005

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What can NUnit do for us?

• Provide Automated Testing
• Not UI Testing
• Programmer tests, not QA tests
• Defects Found Sooner
• Less eggs on fewer faces
• Reduced costs
• Increased Confidence
• XP SP2, Yukon, .Net 2.0
• Refactor Mercilessly

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Simple Demo

• Quick and Easy
• Simple with VS 2005 Team System
• Easy to save results
• Saves repetitive manual testing
• Simple Code Coverage

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NUnit v2.x

• Uses Attributes, not Inheritance
• 'The new version is NUnit as it would have been
  done had it been done in C to begin with Kent
  Beck
• Adding a new Test Class
• TestFixture
• Test
• TestSetup TestTearDown
• TestFixtureSetup TestFixtureTearDown
• Doing the tests
• Assert.AreEqual(..)

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Useful Tips

• Destroy all Singletons - (IDisposable)
• And any other state!!
• Testing stateless classes is easiest
• Migrating NUnit tests is easy

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Bigger Demo

• Multi-Date Formats
• Break the code and see Red
• The errors is found very quickly
• Benefits?
• Less loss of face for silly errors
• Lower cost finding error close to source

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The V Model Testing Taxonomy