--test-concurrency

测试运行器 CLI 可以并发执行的最大测试文件数。如果 --test-isolation 设置为 'none'，则忽略此标志，并且并发数为一。否则，并发数默认为 os.availableParallelism() - 1。

【The maximum number of test files that the test runner CLI will execute concurrently. If --test-isolation is set to 'none', this flag is ignored and concurrency is one. Otherwise, concurrency defaults to os.availableParallelism() - 1.】