unit-testing-intro | Introduction to Node.js API Unit Testing | Runtime Evironment library

am learning sinon and nodeUnit for nodejs. wrote simple module that handles GET, POST, PUT and DELETE methods.

then started writing unit test. Now there are two sides for my problem:

One being: in GET test when i specify requestMock.method = 'GET'; then run nodeunit test-http-module.js test fails, when reviewing call stack it says POST request failed (handlePostRequest as highlighted in call stack below).

Two being: when changing requestMock.method = 'GET'; to 'POST', 'PUT' or 'DELETE' test still fails no matter what i change! but in latter cases the call stack shows the correct method being directed to.

I think there is a single problem causing the continuous failures and that GET being directed to POST.

please explain what is wrong.

ExpectationError: Unexpected call: writeHead(200, { Content-Type: "text/plain" })

Expectation met: writeHead(200, { Content-Type: "text/plain" }[, ...]) once

at Object.fail (D:\Projects\node-book\node_modules\sinon\lib\sinon\mock-expectation.js:281:25)

at Object.invokeMethod (D:\Projects\node-book\node_modules\sinon\lib\sinon\mock.js:174:25)

at Object.writeHead (D:\Projects\node-book\node_modules\sinon\lib\sinon\mock.js:67:35)

at handlePostRequest (D:\Projects\node-book\modules\http-module.js:8:14)

at Object.handleRequest (D:\Projects\node-book\modules\http-module.js:34:26)

at Object.exports.handleGetRequestTest (D:\Projects\node-book\unit-testing-intro\test-http-module.js:22:21)