Assertions & Tests

Tests let you assert that a response is correct — the right status, the right headers, the right body — and see pass/fail results after each run.

The Tests tab

Each request has a Tests tab. Scripts you write there run after the response arrives, alongside any post-response script, and have access to the same bru, req, and res objects.

test() and expect()

Wrap each assertion in a named test() block. Inside it, use expect() to make the assertion:

test("status is 200", () => {
  expect(res.status).to.equal(200);
});

test("response is fast enough", () => {
  expect(res.responseTime).to.be.below(500);
});

Each test() block reports independently, so one failing assertion does not hide the others.

Common assertions

Goal	Example
Status code	expect(res.status).to.equal(201)
Header present	expect(res.headers["content-type"]).to.include("json")
JSON body field	expect(res.body.user.id).to.equal(42)
Field exists	expect(res.body.token).to.exist
Array length	expect(res.body.items).to.have.lengthOf(3)
Response time	expect(res.responseTime).to.be.below(800)

A typical Tests tab combines several checks:

test("created order", () => {
  expect(res.status).to.equal(201);
  expect(res.body.order.id).to.exist;
  expect(res.body.order.status).to.equal("pending");
});

The Test Results view

After a request runs, the Test Results view lists every test() block with a pass or fail marker. Failed assertions show what was expected versus what was received, so you can diagnose the difference quickly.

Running tests for a whole collection

You can run an entire collection in one pass. Every request’s tests execute in order, and the Test Results view aggregates pass/fail counts across all of them — useful for regression-checking an API after a change.

Tip

Combine tests with post-response scripts: extract a value with bru.setVar, then assert on it with expect() in the same Tests tab.

See the Scripting API reference for the full test and expect API.