Used in Terraform test

The optional test block defines the configuration of the test file, allowing you to configure how the framework executes its runs. The block has the following fields:

# with_config.tftest.hcl
test {
  parallel = true
}
Field or Block NameDescriptionDefault Value
parallelAn optional boolean attribute. If true, Terraform executes all eligible run blocks simultaneously. Refer to Parallel execution for more information.false

https://developer.hashicorp.com/terraform/language/tests