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Contract First Development with Microsoft Code Contracts and Microsoft Pex at Silicon Valley Code Camp 2011 (2011-10-08)

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Theo Jungeblut
Theo Jungeblut

Presentation about the advantage using Microsoft Code Contracts and Pex for writing better maintainable and testable applications.

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Silicon Valley Code Camp Contract-First Development with > Microsoft Code Contracts and Microsoft Pex Foothill College, October 8nd 2011
Theo Jungeblut • Senior Software Developer at Omnicell Inc. in Mountain View • Has been designing and implementing .NET based applications , components and frameworks for more than 8 years • Previously worked in factory automation with focus on component based software and framework development for 3 ½ years theo@csharp-lighthouse.com • Degree in Software Engineering and Network Communications www.csharp-lighthouse.com
Overview • How to measure Code Quality • Principles and Practices • Microsoft Code Contracts • How is your Code Coverage? • Microsoft Pex & Moles • Time for Source Code • Summary • Q&A • References
Does writing Clean Code make us more efficient?
Contract First Development with Microsoft Code Contracts and Microsoft Pex at Silicon Valley Code Camp 2011 (2011-10-08)
Clean Code??? We are here for Code Contracts, Pex and Mole!!
Clean Code is maintainable Source code must be: • readable & well structured • extensible • testable
Clean Code is maintainable Source code must be: • readable & well structured • extensible • testable
Code Maintainability * Principles Patterns Containers Why? How? What? Extensibility Clean Code Tool reuse * from: Mark Seemann’s “Dependency Injection in .NET” presentation Bay.NET 05/2011
Don’t repeat yourself (DRY)
Don’t repeat yourself (DRY) by Andy Hunt and Dave Thomas in their book “The Pragmatic Programmer” // Code Copy and Paste Method // DRY Method public Class Person public Class Person { { public string FirstName { get; set;} public string FirstName { get; set;} public string LastName { get; set;} public string LastName { get; set;} public Person(Person person) public Person(Person person) { { this.FirstName = string.IsNullOrEmpty(person.FirstName) this.FirstName = person.FirstName.CloneSecured(); ? string.Empty : (string) person.FirstName.Clone(); this.LastName = person.LastName.CloneSecured(); } this.LastName = string.IsNullOrEmpty(person.LastName) ? string.Empty : (string) person.LastName.Clone(); public object Clone() } { return new Person(this); public object Clone() } { } return new Person(this); } } public static class StringExtension { public static string CloneSecured(this string original) { return string.IsNullOrEmpty(original) ? string.Empty : (string)original.Clone(); } }
Separation of Concerns (SoC) Single Responsibility Principle (SRP)
Separation of Concerns (SoC) probably by Edsger W. Dijkstra in 1974 • “In computer science, separation of concerns (SoC) is the process of separating a computer program into distinct features that overlap in functionality as little as possible. •A concern is any piece of interest or focus in a program. Typically, concerns are synonymous with features or behaviors. “ http://en.wikipedia.org/wiki/Separati on_of_Concerns
Single Responsibility Principle (SRP) by Robert C Martin “Every object should have a single responsibility, and that responsibility should be entirely encapsulated by the class.” http://en.wikipedia.org/wiki/Single_responsibility_principle public class Logger : ILogger { public Logger(ILoggingSink loggingSink) {} public void Log(string message) {} } http://www.ericalbrecht.com
.NET Tools and their Impact Tool name Positive Impact Negative Impact Resharper compiling ++++ VS responsiveness -- FxCop code quality ++ compiling time - StyleCop code consistency +++ compiling time - StyleCop plugin compiling time +++ VS responsiveness -- for Resharper Ghost Doc automated docs potentially worse doc Spell Checker fewer spelling errors ++ performance -- Code Contracts testability, quality ++ compiling time -- Pex & Moles automated test ++ compiling time --
• Design-by-Contract programming • Improved testability • Static verification • API documentation integration with Sandcastle http://msdn.microsoft.com/en-us/devlabs/dd491992
The Basic Idea public class Logger : ILogger{ public void Log(string message) { . Validation Input 1.) Parameter Assignment 2.) Execute method logics . Optional State Validation/Invariants 3.) Possible Return Statement . Result Validation }}
Method Overview Code Contracts User Manual, 5.3 Contract Ordering, page 22
Runtime Checking Levels Code Contracts User Manual, 6.2.1 Runtime Checking Level, page 24
Argument Validation Code Contracts User Manual, 5.1 Argument Validation and Contracts, page 18
Contract First Development with Microsoft Code Contracts and Microsoft Pex at Silicon Valley Code Camp 2011 (2011-10-08)
How is your Code Coverage?
How is your Code Coverage? • Writing enough Unit Tests takes Time • Writing basic Unit Tests is not Fun
Microsoft Pex & Moles • Pex automatically generates test suites with high code coverage. • Moles allows to replace any .NET method with a delegate. http://research.microsoft.com/en-us/projects/pex/
Microsoft Sandcastle “Sandcastle produces accurate, MSDN style, comprehensive documentation by reflecting over the source assemblies and optionally integrating XML Documentation Comments. Sandcastle has the following key features: • Works with or without authored comments • Supports Generics and .NET” http://sandcastle.codeplex.com/
Time for Visual Studio as well all love code, right !?
Summary Code Contracts • Code Contracts: – Better readable source code (SoC, SRP, DRY) – Static Analysis for Code Contracts – Impacts the compile time • Pex & Mole: – Generated paramized Unit tests – Moles allows mocking also of static • Conclusion ??
Q&A Downloads, Feedback & Comments: theo@csharp-lighthouse.com www.csharp-lightouse.com www.speakerrate.com/theoj Graphic by Nathan Sawaya courtesy of brickartist.com
References Code Contracts • See Dino Esposito’s MSM Magazine series on Code Contracts • http://msdn.microsoft.com/en-us/devlabs/dd491992.aspx • http://research.microsoft.com/en-us/projects/contracts/ • http://www.codeproject.com/KB/cs/CodeContracts.aspx • http://sachabarber.net/?p=811 • http://blogs.msdn.com/b/somasegar/archive/2009/02/23/devlabs-code-contracts-for-net.aspx • http://designcoderelease.blogspot.com/2011/01/pex-moles.html • http://www.agilitylux.com/practices/code-contracts-by-example/ Pex & Mole • http://research.microsoft.com/en-us/projects/pex/ Sandcastle • http://sandcastle.codeplex.com/ • http://stackoverflow.com/questions/3579655/does-sandcastle-support-code-contracts
Clean Code Why Clean Code matters Foothill College, October 9nd 2011
Please fill out the online feedback, and… … thanks for you attention! And visit and support the Bay.net User Group http://baynetug.org

More Related Content

Contract First Development with Microsoft Code Contracts and Microsoft Pex at Silicon Valley Code Camp 2011 (2011-10-08)

  • 1. Silicon Valley Code Camp Contract-First Development with > Microsoft Code Contracts and Microsoft Pex Foothill College, October 8nd 2011
  • 2. Theo Jungeblut • Senior Software Developer at Omnicell Inc. in Mountain View • Has been designing and implementing .NET based applications , components and frameworks for more than 8 years • Previously worked in factory automation with focus on component based software and framework development for 3 ½ years theo@csharp-lighthouse.com • Degree in Software Engineering and Network Communications www.csharp-lighthouse.com
  • 3. Overview • How to measure Code Quality • Principles and Practices • Microsoft Code Contracts • How is your Code Coverage? • Microsoft Pex & Moles • Time for Source Code • Summary • Q&A • References
  • 4. Does writing Clean Code make us more efficient?
  • 6. Clean Code??? We are here for Code Contracts, Pex and Mole!!
  • 7. Clean Code is maintainable Source code must be: • readable & well structured • extensible • testable
  • 8. Clean Code is maintainable Source code must be: • readable & well structured • extensible • testable
  • 9. Code Maintainability * Principles Patterns Containers Why? How? What? Extensibility Clean Code Tool reuse * from: Mark Seemann’s “Dependency Injection in .NET” presentation Bay.NET 05/2011
  • 11. Don’t repeat yourself (DRY) by Andy Hunt and Dave Thomas in their book “The Pragmatic Programmer” // Code Copy and Paste Method // DRY Method public Class Person public Class Person { { public string FirstName { get; set;} public string FirstName { get; set;} public string LastName { get; set;} public string LastName { get; set;} public Person(Person person) public Person(Person person) { { this.FirstName = string.IsNullOrEmpty(person.FirstName) this.FirstName = person.FirstName.CloneSecured(); ? string.Empty : (string) person.FirstName.Clone(); this.LastName = person.LastName.CloneSecured(); } this.LastName = string.IsNullOrEmpty(person.LastName) ? string.Empty : (string) person.LastName.Clone(); public object Clone() } { return new Person(this); public object Clone() } { } return new Person(this); } } public static class StringExtension { public static string CloneSecured(this string original) { return string.IsNullOrEmpty(original) ? string.Empty : (string)original.Clone(); } }
  • 12. Separation of Concerns (SoC) Single Responsibility Principle (SRP)
  • 13. Separation of Concerns (SoC) probably by Edsger W. Dijkstra in 1974 • “In computer science, separation of concerns (SoC) is the process of separating a computer program into distinct features that overlap in functionality as little as possible. •A concern is any piece of interest or focus in a program. Typically, concerns are synonymous with features or behaviors. “ http://en.wikipedia.org/wiki/Separati on_of_Concerns
  • 14. Single Responsibility Principle (SRP) by Robert C Martin “Every object should have a single responsibility, and that responsibility should be entirely encapsulated by the class.” http://en.wikipedia.org/wiki/Single_responsibility_principle public class Logger : ILogger { public Logger(ILoggingSink loggingSink) {} public void Log(string message) {} } http://www.ericalbrecht.com
  • 15. .NET Tools and their Impact Tool name Positive Impact Negative Impact Resharper compiling ++++ VS responsiveness -- FxCop code quality ++ compiling time - StyleCop code consistency +++ compiling time - StyleCop plugin compiling time +++ VS responsiveness -- for Resharper Ghost Doc automated docs potentially worse doc Spell Checker fewer spelling errors ++ performance -- Code Contracts testability, quality ++ compiling time -- Pex & Moles automated test ++ compiling time --
  • 16. • Design-by-Contract programming • Improved testability • Static verification • API documentation integration with Sandcastle http://msdn.microsoft.com/en-us/devlabs/dd491992
  • 17. The Basic Idea public class Logger : ILogger{ public void Log(string message) { . Validation Input 1.) Parameter Assignment 2.) Execute method logics . Optional State Validation/Invariants 3.) Possible Return Statement . Result Validation }}
  • 18. Method Overview Code Contracts User Manual, 5.3 Contract Ordering, page 22
  • 19. Runtime Checking Levels Code Contracts User Manual, 6.2.1 Runtime Checking Level, page 24
  • 20. Argument Validation Code Contracts User Manual, 5.1 Argument Validation and Contracts, page 18
  • 22. How is your Code Coverage?
  • 23. How is your Code Coverage? • Writing enough Unit Tests takes Time • Writing basic Unit Tests is not Fun
  • 24. Microsoft Pex & Moles • Pex automatically generates test suites with high code coverage. • Moles allows to replace any .NET method with a delegate. http://research.microsoft.com/en-us/projects/pex/
  • 25. Microsoft Sandcastle “Sandcastle produces accurate, MSDN style, comprehensive documentation by reflecting over the source assemblies and optionally integrating XML Documentation Comments. Sandcastle has the following key features: • Works with or without authored comments • Supports Generics and .NET” http://sandcastle.codeplex.com/
  • 26. Time for Visual Studio as well all love code, right !?
  • 27. Summary Code Contracts • Code Contracts: – Better readable source code (SoC, SRP, DRY) – Static Analysis for Code Contracts – Impacts the compile time • Pex & Mole: – Generated paramized Unit tests – Moles allows mocking also of static • Conclusion ??
  • 28. Q&A Downloads, Feedback & Comments: theo@csharp-lighthouse.com www.csharp-lightouse.com www.speakerrate.com/theoj Graphic by Nathan Sawaya courtesy of brickartist.com
  • 29. References Code Contracts • See Dino Esposito’s MSM Magazine series on Code Contracts • http://msdn.microsoft.com/en-us/devlabs/dd491992.aspx • http://research.microsoft.com/en-us/projects/contracts/ • http://www.codeproject.com/KB/cs/CodeContracts.aspx • http://sachabarber.net/?p=811 • http://blogs.msdn.com/b/somasegar/archive/2009/02/23/devlabs-code-contracts-for-net.aspx • http://designcoderelease.blogspot.com/2011/01/pex-moles.html • http://www.agilitylux.com/practices/code-contracts-by-example/ Pex & Mole • http://research.microsoft.com/en-us/projects/pex/ Sandcastle • http://sandcastle.codeplex.com/ • http://stackoverflow.com/questions/3579655/does-sandcastle-support-code-contracts
  • 30. Clean Code Why Clean Code matters Foothill College, October 9nd 2011
  • 31. Please fill out the online feedback, and… … thanks for you attention! And visit and support the Bay.net User Group http://baynetug.org