Function.prototype.bindFake = function(context) {
    let fn = this;
    let arr = Array.prototype.slice.call(arguments, 1);
    return function() {
        let innerArgs = Array.prototype.slice.call(arguments);
        let args = arr.concat(innerArgs);
        fn.apply(context, args);
    }
}

Function.
 
prototype.callFake = function(context) {
    let context = context || window;
    context.fn = this;
    let arr = [];
    let result;
    for(let i = 1; i < arguments.length; i++) {
        arr.push('arguments[' + i + ']');
    }
    if (arr) {
        result = eval('context.fn(' + arr + ')');
    }
 
 else {
        result = context.fn();
    }
    delete context.fn;
    return result;
}

Function.prototype.applyFake = function(context, arr) {
    let context = context || window;
    context.fn = this;
    let result;
    if (arr) {
        let args = [];
        for(let i = 0; i< arr.length; i++
 
) {
            args.push('arr[' + i + ']');
        }
        result = eval('context.fn(' + args + ')');
    } else {
        result = context.fn();
    }
    
    delete context.fn;
    return result;
}