less.js/test/browser/runner-modify-vars-spec.js

var alreadyRun = false;

describe("less.js modify vars", function() {
    beforeEach(function(){
	// simulating "setUp" or "beforeAll" method
	var lessOutputObj;
        if (alreadyRun)
	    return ;
	
        alreadyRun = true;

        // wait until the sheet is compiled first time
        waitsFor(function() {
	    lessOutputObj = document.getElementById("less:test-less-simple");
            return lessOutputObj!==null;
        }, "first generation of less:test-less-simple", 7000);

	// modify variables
        runs(function() {
	    lessOutputObj.type="not compiled yet";
	    less.modifyVars({var1: "green", var2: "purple"});
        });

        // wait until variables are modified
        waitsFor(function() {
	    lessOutputObj = document.getElementById("less:test-less-simple");
            return lessOutputObj!==null && lessOutputObj.type==="text/css";
        }, "second generation of less:test-less-simple", 7000);
	
    });
	
    testLessEqualsInDocument();
    it("Should log only 2 XHR requests", function() {
        var xhrLogMessages = logMessages.filter(function(item) {
            return /XHR: Getting '/.test(item);
        })
        expect(xhrLogMessages.length).toEqual(2);
    });
});