Customizing the 'on' Directive: Advanced Event Usage

In a GitHub repository, you have two workflows: build.yml and test.yml. The build.yml workflow handles the build process, while the test.yml workflow runs tests on the built artifacts. The test.yml workflow gets called from the build.yml workflow using the workflow_call feature.

build.yml:

name: Build Workflow

on:
  push:
    branches:
      - main

jobs:
  build:
    runs-on: ubuntu-latest

    steps:
      # Build steps here

  post-build:
    needs: build
    runs-on: ubuntu-latest

    steps:
      - name: Call Test Workflow
        uses: ??
        with:
          parameter1: value1
          parameter2: value2

Structure of folders:

.github/
└── workflows
    ├── build.yml
    └── test.yml

Which expression from the provided YAML configuration can you use to call the test.yml workflow from the build.yml workflow?