Sinon error Attempted to wrap function which is already wrapped

Question

Though there is a same question here but I could not find answer to my problem so here goes my question:

I am testing my node js app using mocha and chai. I am usin

Answer 1

This error is due to not restoring the stub function properly. Use sandbox and then create the stub using the sandbox. After each test inside the suite, restore the sandbox

  beforeEach(() => {
      sandbox = sinon.createSandbox();
      mockObj = sandbox.stub(testApp, 'getObj', fake_function)
  });

  afterEach(() => {
      sandbox.restore();
  });

Answer 2

For anyone running into this issue, if you stub or spy on the entire object, and you later do

sandbox.restore()

You'll still get the error. You have to stub/spy the individual methods.

I wasted forever trying to figure out what was wrong.

sinon-7.5.0

Answer 3

function stub(obj, method) {
     // try to remove any existing stub in case it exists
      try {
        obj[method].restore();
      } catch (e) {
        // eat it.
      }
      return sinon.stub(obj, method);
    }

and use this function when creating stubs in tests. It will resolve 'Sinon error Attempted to wrap function which is already wrapped' error.

example:

stub(Validator.prototype, 'canGeneratePayment').returns(Promise.resolve({ indent: dTruckIndent }));