Scripts and tests

Every request, folder and collection has two JavaScript scripts, in the Scripts tab:

• Pre-request — runs before sending and can change the request.
• Post-response (the tests) — runs once the response arrives, with assertions.

Scripts run isolated, in a separate process with a timeout (5 s by default, configurable in wttp.yaml): no require, no process, no disk access. A script error or timeout never freezes the app.

Execution order

Pre-request runs outside in (collection → folder → request) and tests run inside out. An exception in a pre-request aborts the send, with a clear message.

An example: login that stores the token

// Post-response of the "Login" request
test("status is 200", () => expect(res.status).toBe(200));
wttp.setVar("token", res.json.token);

With a Bearer {{token}} inherited from the collection, the next request goes out authenticated. wttp.setVar writes to the active environment, on disk, as soon as the script finishes — and never overwrites a Secret variable.

What's available in a script

Global	Where	What for
wttp	both	setVar/getVar (environment), setCollectionVar/getCollectionVar
req	pre-request	the resolved request, mutable
res	post-response	the response (read-only): status, headers, body, json, timing
test	post-response	declares an assertion
expect	post-response	toBe, toEqual, toBeTruthy, toContain, toHaveProperty, toMatch
console	both	log/warn/error, shown in the Tests tab

The editor has autocomplete for the whole API, snippets and flags syntax errors. Results appear in the response's Tests tab, and the status bar summarizes failures.

Full reference: Scripting API.