Description
Hello everyone. Thanks for maintaining this awesome tool. I'm facing an issue while trying to test a simple endpoint headers. I would highly appreciate any help you could bring.
Describe the bug
Node.js version: v22.12.0
OS version: Fedora Linux 41
Description:
I just started using supertest today (in its latest version from NPM), with the goal of testing the following simple endpoint:
router.get('/health', (_, response) => {
response.setHeader('Content-Type', 'text/plain');
response.end('OK');
})Actual behavior
Having written the following test:
it('Should return a 200 HTTP status code', async () => {
const response = await request(application).get('/health');
expect(response.headers['Content-Type']).toBe('text/plain');
})I encounter a failure, because of an unmet expectation on the Content-Type header, in the form of:
Expected: "text/plain"
Received: undefined
However, the following expectation works as expected:
expect(response.headers['content-type']).toBe('text/plain');
Expected behavior
Having verified through Postman that my API returns the correct header:
I expect to be able to assert the Content-Type header, with that exact casing.
Code to reproduce
// My app file
const express = require('express');
const healthcheckRouter = require('./shared/healthcheck/router');
// Server setup
const application = express();
application.use('/health', healthcheckRouter);
module.exports = {
application
}
// My router file
const express = require('express');
const healthcheckRouter = express.Router();
healthcheckRouter.get('/', (_, response) => {
response.setHeader('Content-Type', 'text/plain');
response.end('OK');
})
module.exports = healthcheckRouter;
// My test file
const request = require('supertest');
const { application } = require('../../application');
describe('Health check', () => {
it('Should return a 200 HTTP status code', async () => {
const response = await request(application).get('/health');
expect(response.headers['Content-Type']).toBe('text/plain');
})
})
As an additional note (knowing that it probably belongs to a separated issue), having verified with Postman that the endpoint provided effectively returns "OK", adding the following assertion:
expect(response.body).toBe('OK')Fails with the following:
Expected: "OK"
Received: {}
Checklist
- [ x ] I have searched through GitHub issues for similar issues.
- [ x ] I have completely read through the README and documentation.
- [ x ] I have tested my code with the latest version of Node.js and this package and confirmed it is still not working.