Evergine.Mocks 2022.9.28.2

Evergine.Mocks

Introduction

Library to enable testing applications made with Evergine, inspired on Xamarin.Forms.Mocks.

Goals:

• Enable testing components and behaviors

Out of scope:

• Enable testing drawables or anything related to rendering

Approach

The most of our applications contain a bunch of components (it-self, or behaviors/drawables) which contain logic. Such components, usually, consume other artifacts from outside:

• other components
• services
• managers
• entities from its hierarchy

Beacause of this, isolating a component for testing is quite complicated. However, we can rely on a mock Windows System which, in a headless fashion, replicates the same behavior the app would have.

Status

• running single update-draw loop on demand
• reading actual Content
• BindComponent attribute
• BindService attribute
• Camera3D.Display
• mock KeyboardDispatcher
• mock MouseDispatcher
• mock TouchDispatcher

Changes needed in our projects

• Leave Application.Initialize() empty: refactor its entire logic into a separate public method, called from each WindowsSystem
  • This is needed to avoid tests to set the ScreenContext up and navigate to an actual Scene by default

windowsSystem.Run(
    () =>
    {
        // Pull initialization logic from here...
        application.Initialize();
        // to here
        application.NavigateToMainScene();
    },
    () =>
    {
        [...]
    });

• Execute tests sequentially: Evergine currently does not support running tests in parallel
  • You can see how to do it with xUnit here

Changes needed in Evergine

• New GraphicsBackend value: Mock, None, Test
• Maybe: Allow running tests in parallel (it seems there are some static references preventing such)