I am working with `process.platform` and want to stub that string value to fake different OSes.

(this object is generated out of my reach, and I need to test against different values it can take on)

Is it possible to stub/fake this value?
---------------------------------------

I have tried the following without any luck:

```
stub = sinon.stub(process, "platform").returns("something")

```

I get the error `TypeError: Attempted to wrap string property platform as function`

The same thing happens if I try to use a mock like this:

```
mock = sinon.mock(process);
mock.expects("platform").returns("something");

```