The CrossBrowserTesting.com App can handle automatically launching tests if given proper URLs.  In fact, that’s how we handle calls to Run Again or Run Live Test from within the app.  Here’s the URL structure and what you need to know to generate your own auto-launching links:

Live Tests

https://app.crossbrowsertesting.com/livetests/run?browser=iPhone6sPlus-iOS9|MblSafari9.0|1080x1920&url=http%3A%2F%2Fwww.google.com&launch=true

Screenshot Tests

https://app.crossbrowsertesting.com/screenshots/run?browser_list_name=popular+browsers&url=http%3A%2F%2Fwww.google.com&launch=true

A closer look at the URL parameters:

url

The URL you want the browser to launch for testing. (should be url-encoded; in the above example, :// is replaced with %3A%2F%2F because those characters are not a standard part of a URL)

launch

This is how the app knows to automatically launch the test. Must be set to ‘true’.

browser (Live Tests)

The browser you want to run the test against. This parameter can be used to provide OS/device, browser type & version, as well as resolution. The API call to list browsers is one way to get the api_names for each configuration.
Format: os_api_name|browser_api_name|resolution

browser_list_name (Screenshot Tests)

The name of a preset list of browsers you have created for your account. You can use “Popular Browsers” which is a system level browser list available to all users.

Note: If a user is not logged in when accessing an auto-launch link, the user will be taken to a login form before continuing. A browser_list_name must belong to the account logged in or the master account holder.