Implement a response time calculation to test API response latency.

Is your feature request related to a problem? Please describe. I would like to test my API endpoints latency by adding a test that measures it. Currently, Postman uses responseTime:

pm.test("Response time is less than 1000ms", function () {
    pm.expect(pm.response.responseTime).to.be.below(1000);
});

Describe the solution you’d like After talking to @reynolek - the solution would be seem to be as follows:

“It would need a variable added to the request config (a start time), and then once the request has returned, calculate the time between return and start time in milliseconds, and include that in the data being returned by send.”

Additional context Looking to move away from Postman, so hoping to have this added. Thank you!

[amaaniqbal]

Thanks a lot for the detailed overview @develohpanda! I will try creating a PR for this today itself.

[develohpanda]

Hi @amaaniqbal!

When writing a unit test, the insomnia class instance for Mocha is set up here: https://github.com/Kong/insomnia/blob/5f4c19da35e90ffa2f3ae27e9b309ee48f9d4e16/packages/insomnia-testing/src/run/run.ts#L30-L30

This class will use a sendRequest callback if it exists in the options sent to the constructor, and use axios as a fallback. https://github.com/Kong/insomnia/blob/5f4c19da35e90ffa2f3ae27e9b309ee48f9d4e16/packages/insomnia-testing/src/run/insomnia.ts#L78-L80

That options object in the constructor of Insomnia, is sent either from insomnia-app or insomnia-inso: https://github.com/Kong/insomnia/blob/6e073c8a38f4b9c783786e3a2c149a10c7d38dec/packages/insomnia-app/app/ui/components/wrapper-unit-test.tsx#L279-L283

https://github.com/Kong/insomnia/blob/5f4c19da35e90ffa2f3ae27e9b309ee48f9d4e16/packages/insomnia-inso/src/commands/run-tests.ts#L97-L103

This means, because all of the entry points in the app and the CLI actually provide the sendRequest callback, axios is never consumed. (As an aside, we can likely remove axios, it was a remnant of the initial build PoC)

Finishing off the links, sendRequest is defined here, exposing Insomnia’s networking logic as a standalone library: https://github.com/Kong/insomnia/blob/6e073c8a38f4b9c783786e3a2c149a10c7d38dec/packages/insomnia-app/app/common/send-request.ts#L41-L62

The response returned from that sendAndTransform function is what is available to you in unit tests.

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It appears that the elapsed time for a request is already available on the res response object in sendAndTransform! So if you add it here, in theory you should have the elapsed time available for you in unit tests

In which format is the response time desired? I suppose returning responseTime in seconds rounded to 3 decimal places would be recommended.

In terms of precision, I would stick with returning the time in ms with no decimal places, since working in milliseconds is fairly standard in JS.