Fake Display Coordinator Connector

The BUILD.gn in this directory a component package named fake-display-coordinator-connector. It's a testing double of the display-coordinator-connector package.

It publishes the fuchsia.hardware.display.Provider service that can be used for hermetic testing without real hardware dependency.

Introduction

The goal of fake-display-coordinator-connector is to provide a display engine driver (fake-display) and a display coordinator driver within a hermetic testing environment. This removes the dependency on acquiring the display coordinator, allowing tests to run in display-less environments hermetically and allowing multiple display coordinator and display driver instances to co-exist.

Usage

Realms should declare a child component in its component manifest for the display coordinator connector. The child must be named display-coordinator-connector to make its capabilities be correctly routed.

They should also include the corresponding shard component manifest file fake_display_coordinator_connector.shard.cml to route required capabilities to the display-coordinator-connector child.

They should also explicitly offer the fuchsia.hardware.display.Provider service from display-coordinator-connector to clients (for example, Scenic).

For example, here is an excerpt of ui_test_realm (//src/ui/testing/ui_test_realm/meta/scenic.shard.cml) declaring a fake display coordinator connector from its own package, offering parent capabilities to the display coordinator connector, and providing the fuchsia.hardware.display.Provider service to Scenic:

{
  include: [
    "//src/graphics/display/testing/fake-coordinator-connector/meta/fake_display_coordinator_connector.shard.cml",
  ],
  children: [
    {
      name: "display-coordinator-connector",
      url: "#meta/display-coordinator-connector.cm",
    },
  ],
  offer: [
    {
      protocol: ["fuchsia.hardware.display.Provider"],
      from: "#display-coordinator-connector",
      to: ["#scenic"],
    },
  ],
}