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TDD IN AN IoT WORLD
Charles Korn
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IoT?
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TDD IN AN IoT WORLD Charles Korn 1 IoT? 2 What is TDD? 3 - - PowerPoint PPT Presentation
TDD IN AN IoT WORLD Charles Korn 1 IoT? 2 What is TDD? 3 - - PowerPoint PPT Presentation
TDD IN AN IoT WORLD Charles Korn 1 IoT? 2 What is TDD? 3 Test-driven development 4 Test-driven development Test-driven design 5 Its not just about testing your code 6 Its also about designing your code to be testable 7 CODE
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What is TDD?
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Test-driven development
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Test-driven development Test-driven design
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It’s not just about testing your code
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It’s also about designing your code to be testable
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CODE THAT IS DESIGNED TO BE EASY TO TEST
Image credit: weedist.com
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Code that is easy to test is: small simple has a single responsibility
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Clean code is: small simple has a single responsibility
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But how?
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Red Green Refactor
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Image credits: unicornsrule.com and Nicolò Bertoncin
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Development environment
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Image credits: Michael Bundscherer, Kevin Kwok, Nicolò Bertoncin, Rflor
≈ ≈ ≉
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Hardware constraints
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Long write-run-debug cycle
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3 6 9 12 Host Target
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Might not have target hardware
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Development and production environment differences Hardware constraints Long write-run-debug cycle Target hardware availability
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Red Green Refactor Test on target hardware
Image credits: Kevin Kwok and Nicolò Bertoncin
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Compile Flash Run Compile Flash Run
First 50% of tests Second 50% of tests
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Lots of low-level interactions with hardware
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Avoid direct interactions with hardware (or: use good abstractions)
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PINA |= (1 << LED_PIN)
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turnOn(LED_PIN) expect(PINA & 0x04 == 1)
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expect(getState(LED_PIN) == ON)
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Performance concerns
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Image credit: scmp.com
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IT’S A TRAP!
Image credit: Lucasfilm
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Know what ‘good enough’ looks like Know why it’s required Have a repeatable way to measure it The tests can help you
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C and C++
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Image credit: memecenter.com
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Link-time fakes
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Function pointers
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Virtual classes
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Image credit: XKCD
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Go forth and TDD
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Before I go…
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Image credit: blog.tkjelectronics.dk
https://github.com/charleskorn/stm32f4-project-template
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TDD for circuit design
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Charles Korn charleskorn.com