Duplicate function name affecting Jasmine tests in Meteor

Question

I have recently started working with Meteor, and trying to start off as I mean to go on by testing well. To this end, I am using the Velocity test runner and using Jasmine for the actual tests.

Take the very simple case where I have a file in the server directory called hello.js, which contains our old favourite

var helloWorld = function () {
    return "Hello World";
};

Then in my test directory, well 'tests/jasmine/server/unit' I have a test file sampleTest.js containing the basic test suite

describe("Hello World", function() {
    it("should return hello world", function() {
        expect(helloWorld()).toBe("Hello World");
    });
});

Velocity reports all tests passing, everyone is happy. If I change the original helloWorld function to return something different, the test fails as expected.

If, however, a second function, of the same name with a different output existed somewhere in the project, e.g.

var helloWorld = function () {
    return "Goodbye World";
};

Then this would break the test, but the other version of it passes the test.

Extrapolating from this simplified example, how then do I ensure each function is uniquely named to avoid this problem?

Is my question more a result of my incomplete grasp of Meteor fundamentals (or JS/testing fundamentals in general)?