Test driven development for Invisible Hardware Samuel Gaist - - PowerPoint PPT Presentation

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Test driven development for Invisible Hardware Samuel Gaist - - PowerPoint PPT Presentation

Apr 05, 2023 40 likes •302 views

Test driven development for Invisible Hardware Samuel Gaist Edeltech Ltd Switzerland jeudi, 9 octobre 14 Samuel Gaist Software Development Engineer Partner at Edeltech Ltd Developer at IDIAP Research Institute Qt Experience User

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Test driven development for Invisible Hardware

Samuel Gaist Edeltech Ltd Switzerland

jeudi, 9 octobre 14

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Samuel Gaist

Software Development Engineer

  • Partner at Edeltech Ltd
  • Developer at IDIAP Research Institute

Qt Experience

  • User since Qt 3.2
  • Contributor for ~ 2 years (QtCore, QtGui, QtMacExtras)
  • 10’000+ posts in Qt Forum

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Outline

  • 1. AgiScan, a film scanning application
  • 2. Invisible Devices
  • 3. Test Driven Development with Invisible Devices
  • 4. Demo
  • 5. Wrap Up
  • 6. Q/A

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  • 1. AgiScan, a film scanning application

Embedded App Proprietary Qt Desktop App Mac OS / Windows

USB Audio/Video

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  • 1. AgiScan, a film scanning application

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  • 1. AgiScan, a film scanning application

The Application (AgiScan) requires the device (Film scanner).

  • to setup the GUI since the App supports different scanner

models with different hardware options.

  • to setup the audio and video capture subsystems since

each scanner model produces different resolutions, image formats, etc…

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  • 2. Invisible Devices
  • It can’t be moved next to your desk.

because it’s too big or heavy

  • It doesn’t exist yet.

next week, promised

  • It exists but you can’t have it.

because someone needs it or it’s too expensive

  • The only one we have has been sold yesterday.

we’ll build you a new one if we get an order…

200k€

200kg

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  • 2. Invisible Devices

I can’t have one = INVISIBLE So how do I develop my Application ?

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  • 3. Test Driven Development with

Invisible Devices

Write a Mock Object

to mimic the behaviour of the Invisible Device in controlled ways.

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  • 3. Test Driven Development with

Invisible Devices

Use an Adapter Object

to communicate with the device when it is available,

  • r with the Mock Object.

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  • 3. Test Driven Development with

Invisible Devices

Apply TDD principles

because we want to sleep well.

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  • 3. Test Driven Development with

Invisible Devices

Run Test (Re-)Write a Test Run all Tests Write Code Refactor / Clean Code

PASS FAIL FAIL PASS

TDD Friendly Reminder

http://en.wikipedia.org/wiki/Test-driven_development

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  • 3. Test Driven Development with

Invisible Devices

TDD Benefits

  • 1. Know how your code works.
  • 2. Know that your code works.
  • 3. Help other developers understand your code.
  • 4. Know when you break something.

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Levels of testing

UNIT TEST Each class, e.g. the Mock Object FUNCTIONAL TEST Several classes, e.g. Mock Object + Adapter SYSTEM TEST Application: e.g. Scenario based user interaction, Squish

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  • 3. Test Driven Development with

Invisible Devices

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  • 3. Test Driven Development with

Invisible Devices

Project Architecture

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#include <QtTest> #include <QCoreApplication> #include "mycoolclass.h" class UnitTestMyCoolClass : public QObject { Q_OBJECT private Q_SLOTS: void testCase1(); }; QTEST_MAIN(UnitTestMyCoolClass); #include “tst_UnitTestMyCoolClass.moc”

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  • 3. Test Driven Development with

Invisible Devices

Using QTest

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  • 3. Test Driven Development with

Invisible Devices

Let’s write a unit test.

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  • 3. Test Driven Development with

Invisible Devices

Know your Device

  • 1. What interface does it provide ?

Serial Port, Network, …

  • 2. What is the communication protocol ?

Commands, Responses

To write the Mock Object.

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The Mock Object

#include <QObject> class MockDevice : public QIODevice { Q_OBJECT public: MockDevice(); protected: qint64 readData(char *data, qint64 maxlen) Q_DECL_OVERRIDE; qint64 writeData(const char *data, qint64 len) Q_DECL_OVERRIDE; };

  • 3. Test Driven Development with

Invisible Devices

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  • 3. Test Driven Development with

Invisible Devices

Define the Controller API

  • 1. How will the application interact with

the controller ?

Signal/Slots, Events, other ?

  • 2. Level of abstraction

Map the “device lingo” to sensible methods / properties.

To write the Adapter Object.

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#include <QObject> class Controller : public QObject { Q_OBJECT public: Controller(QObject *parent = 0); void setDevice(QIODevice *device); public Q_SLOTS: void doSomething(); void doSomethingElse(); private: QIODevice *_device; }; void Controller::doSomething() { _device->write(DoSomethingCommand); }

QIODevice

QBuffer, QSocket, QSerialPort…

The Adapter Object

  • 3. Test Driven Development with

Invisible Devices

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  • 3. Test Driven Development with

Invisible Devices

Let’s write a controller and test it.

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  • 3. Test Driven Development with

Invisible Devices

Detect the actual device

Using an enumerator (Bonjour, QSerialPortInfo)

Write a Factory

to return the Actual Device or the Mock Device.

and pass it to your Controller using ::setDevice(QIODevice*)

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  • 4. Demo

Demo

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  • 5. Wrap up
  • Using a Mock Device we can develop an application controlling a

device without the actual hardware.

  • The Tests ensure that the Mock Device and the Application work

correctly, and allow developers to reproduce bugs occurring with the actual hardware.

  • The Mock Device can be used to create a Demo Mode.

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Q/A

Questions ?

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