Problems assigning properties to a sinon.stub(obj, "Method") stub.

[Peter Havens]

I may misunderstand how sinon works, but I'd like to do something like the following in a test:

 

# ...

stub = sinon.stub(mod.submod, "Class");

stub.method = sinon.stub();

# ...exercise SUT

# assert that stub.method was called

stub.restore();

# ...

However, in my SUT, when I do:

obj = new mod.submod.Class();

obj.method();

...I get an error about `method` not being defined on `obj`. The `obj` object appears to be a `proxy`, and that `proxy` doesn't have the `method` defined on it. Is there a way to "chain" stubs like this?

Thanks,

Pete

[Christian Johansen]

Hi Peter,

It's _almost_ correct :) The clue is that "Class" is a function, not an object, so to
create stubbed methods for its instances, you need to stub on the prototype, OR
return stubbed objects from the constructor.

Approach #1: Stub prototype

# ...

stub = sinon.stub(mod.submod.Class.prototype, "method");

# ...exercise SUT

# assert that stub.method was called

stub.restore();

# ...

Approach #2: Stub returned objects from constructor (this way you must mimic
the entire API being used):

# ...

stub = sinon.stub(mod.submod, "Class").returns({ method: sinon.stub() }, ...);

# ...exercise SUT

# assert that stub.method was called

stub.restore();

# ...

Christian

--
MVH
Christian