Add flag to set the limit of files to be tested.

[chronark]

This would fix #95

Right now lhci will only test 5 files.
With this PR you can specify the limit to any number or even remove it.

Example:

lhci autorun                            -> Will test 5 files
lhci autorun --collect.numberOfFiles=10 -> Will test 10 files
lhci autorun --collect.numberOfFiles=0  -> Will test all files

Default is still at 5.
A value less or equal than 0 will disable the limit alltogether.

I didn't write any tests yet, because I never wrote CLI tests before, but I'll get around to it soon.
I just wanted to create a PR first to see if you would even consider adding it.

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[chronark]

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[patrickhulce]

thanks very much @chronark! great job hunting down the correct places to add all this :)

as for a test case, you can use

lighthouse-ci/packages/cli/test/collect-static-dir-with-urls.test.js

Lines 18 to 35 in 12619d2

	it('should collect a static dir with explicit URLs', async () => {
	const {stdout, stderr, status} = await runCLI(
	['collect', '-n=1', '--staticDistDir=./', '--url=/child/grandchild.html'],
	{
	cwd: staticDistDir,
	}
	);
	expect(stdout).toMatchInlineSnapshot(`
	"Started a web server on port XXXX...
	Running Lighthouse 1 time(s) on http://localhost:XXXX/child/grandchild.html
	Run #1...done.
	Done running Lighthouse!
	"
	`);
	expect(stderr).toMatchInlineSnapshot(`""`);
	expect(status).toEqual(0);
	}, 180000);

as a model, you'll just want to adjust the arguments to not provide a URL, use the collect-static-dir-without-urls fixture dir instead, and then use your flag to limit the URLs to 1

[chronark]

Alright here we go. Thank you for guiding me @patrickhulce and for your suggestions, I learned something new :)

I added some more tests, so we are testing if it correctly

• limits it to a number
• disables the limit
• defaults to 5

I had to create a new fixture folder but I hope that is fine.

I also added the flag to the configuration.md

[patrickhulce]

this is great thanks @chronark! 🎉 💯