Run an org's namespace tests from JS (untested). NOTE: This only works with v30.0.

RunNSTestsRaw.js

//This example assumes you have a sendRequest method, that can send an AJAX call to Salesforce with Auth header all set up
function runNamespacedTest(namespace) {

	function getTestIdsFromApexClasses(classes) {
		var ids = [];

		for (var i = 0; i < classes.length; i++) {
			var rec = classes[i];
			var st = rec.SymbolTable;
			var mods = st.tableDeclaration.modifiers;
			var modLen = mods.length;
			while (modLen--) {
				if (mods[modLen] === 'TEST') {
					log('Found test: '+st.name);
					ids.push(rec.Id);
				}
			}
		}

		return ids;
	}

	var ns = namespace || '';

	sendRequest("/services/data/v30.0/tooling/query/?q=SELECT%20Id%2C%20SymbolTable%20FROM%20ApexClass%20WHERE%20NamespacePrefix%20%3D%20'"+ns+"'", function(response) {	
		var ids = getTestIdsFromApexClasses(JSON.parse(response).records);

		if (ids.length > 0) {
			sendRequest("/services/data/v30.0/tooling/runTestsAsynchronous/?classids="+encodeURIComponent(ids.join(',')), function(testRunId) {
        		//Do something with the testResult if you want, or view it in the dev console
        	});
		}
	});
}
runNamespacedTest();