Jasmine - How To Mock Undeclared Global Constants

I'm writing JS scripts for a program called eSignal (trading platform). The scripts run inside eSignal and utilize the eSignal API.

I am wanting to write tests for my scripts however I am not sure how I can use Jasmine to mock global constants that eSignal provides.

For example:

function myFunction(){
    //....
    drawShape(Shape.SQUARE)
    //....
}

For the drawShape function, I create a spy for that with drawShapeRelative = jasmine.createSpy(), however I cannot figure out a way to mock the global constant Shape.SQUARE. Because eSignal knows about the constant I do not define it anywhere in my code, so Jasmine says that Shape is not defined.

Inside my script I can run code that will only be executed when the test runs, and only be executed when the scrip runs inside eSignal with

if ( typeof module !== 'undefined' && module.hasOwnProperty('exports') ){
    // Run with test 
}
else{
    // Run with eSignal
}

I feel like I am going to have to do something with this.