**Default:** `false`.

* `files`: {Array} An array containing the list of files to run.

**Default** matching files from [test runner execution model][].

* `inspectPort` {number|Function} Sets inspector port of test child process.

This can be a number, or a function that takes no arguments and returns a

number. If a nullish value is provided, each process gets its own port,

incremented from the primary's `process.debugPort`.

**Default:** `undefined`.

* `testNamePatterns` {string|RegExp|Array} A String, RegExp or a RegExp Array,

that can be used to only run tests whose name matches the provided pattern.

Test name patterns are interpreted as JavaScript regular expressions.

For each test that is executed, any corresponding test hooks, such as

`beforeEach()`, are also run.

**Default:** `undefined`.

* Returns: {TestsStream}