Mocha velocity does not run Meteor call from client at Refresh

I’m new to Mocha velocity and unit testing. I have some problem with my client side test case. When I use find() command to read from database, it returns 'undefined'. But it works correctly only at the meteor restart. I used the following code in my client side.

if (!(typeof MochaWeb === 'undefined')){
        describe("TestClient", function(){
            it("should give a Refid", function(){
                console.log("client test");
                var task = tasksCollection.find({"Refid" : 10}).fetch()[0];
                chai.assert.equal(task.Refid, 10);

My server side code which I used for the same purpose works properly. Can any one help me to resolve this issue…?