packer/command/test-fixtures/parallel/1lock-5wg.json

{
    "builders": [
        {"type": "lock", "name": "build0"},
        {"type": "parallel-test", "name": "build1"},
        {"type": "parallel-test", "name": "build2"},
        {"type": "parallel-test", "name": "build3"},
        {"type": "parallel-test", "name": "build4"},
        {"type": "parallel-test", "name": "build5"}
    ]
}