2025-05-{20,22,23} (6+6 UE): Polymorphic Door Parts, And Some Git#

Git: Update From Upstream#

Current Status: Your Own Fork Is origin#

Recently, we arranged that everyone’s own fork of the upstream project (FH-STECE2023-Org/FH-STECE2023) is the origin of everyone’s local work.

../../../../../../../_images/git-workflow.jpg 
$ git remote -v
origin       git@github.com:you/FH-STECE2023.git (fetch)
origin       git@github.com:you/FH-STECE2023.git (push)

$ git branch -a
* main
  remotes/origin/HEAD -> origin/main
  remotes/origin/main

Update Your Fork#

../../../../../../../_images/update-from-upstream.jpg

  • Create a remote for upstream FH-STECE2023-Org/FH-STECE2023.git (this is done only once):

    $ git remote add upstream https://github.com/FH-STECE2023-Org/FH-STECE2023.git

    $ git remote -v
origin     git@github.com:you/FH-STECE2023.git (fetch)
origin     git@github.com:you/FH-STECE2023.git (push)
upstream   https://github.com/FH-STECE2023-Org/FH-STECE2023.git (fetch)
upstream   https://github.com/FH-STECE2023-Org/FH-STECE2023.git (push)

  • Fetch from upstream. This fetches into a branch upstream/main.

    $ git fetch upstream
... roedel ...

  • Merge upstream/main into your local main branch

    Check that your current branch is main,

    $ git branch
* main

    Merge,

    $ git merge upstream/main

    Note that this is not always so easy - you might have to resolve conflicts.

    Push to default location - your fork,

    $ git push

Exercise: Create Interfaces For Door Parts#

Problem#

  • Door parts (Motor, LightBarrier, PushButton) don’t implement anything that could be of practical use. They don’t do any real hardware stuff.

  • But: They implement functionality that is there for testing

    • LightBarrier::set_state()

    • PushButton::set_state()

    • Motor::get_direction()

    No real light barrier, for example, would have a method set_state()!

  • ⟶ Need hardware parts and mock parts side by side!

Requirement#

../../../../../../../_images/polymorphic.jpg

  • According to From Concrete To Polymorphic (class Sensor), create interfaces (those with virtual and = 0) for

    • LightBarrier (light-barrier.h)

    • PushButton (push-button.h)

    • Motor (motor.h)

    And use those interfaces in Door.

    Attention

    • Door must not use any concrete classes - only interfaces

    • As such, it only includes motor.h, and not motor-mock.h (for example)

  • Slight complication: currently, the mocking implementations are in conflict with the proposed interface names.

    Rename the files e.g. light-barrier.h to light-barrier-mock.h, and the classes e.g. LightBarrier to LightBarrierMock.

Work Instructions#

Exercise takes place in exercises/door-polymorphic/firstname.lastname. Start with the tests. In tests/CMakeLists.txt, you’ll find three more tests which should be able to guide you through the exercise.

add_executable(
  door-tests-polymorphic-joerg.faschingbauer

  motor-tests.cpp
  lightbarrier-tests.cpp
  pushbutton-tests.cpp

  door-tests.cpp

  # --- this is for you :* ---
  # motor-polymorphic-tests.cpp
  # lightbarrier-polymorphic-tests.cpp
  # pushbutton-polymorphic-tests.cpp
)

  • Uncomment them one by one (e.g. motor-polymorphic-tests.cpp)

  • Rename current motor.{h,cpp} to motor-mock.{h,cpp}

  • Create interface for Motor in motor.h

  • Understand and fix compiler errors

  • Run test suite

  • Repeat with next door part

Homework (Until 2025-06-01)#

Complete the exercise, and send pull request.