close
Rslint

    prefer-ending-with-an-expect

    Unreleased

    Configuration

    rslint.config.ts
    import { defineConfig, jestPlugin } from '@rslint/core';

export default defineConfig([
  jestPlugin.configs.recommended,
  {
    rules: {
      'jest/prefer-ending-with-an-expect': 'error',
    },
  },
]);

    Rule Details

    Prefer ending a test body with an assertion. A test whose last statement is not an expect (or another configured assert function) often indicates unfinished work that may pass silently.

    Examples of incorrect code for this rule:

    it('lets me change the selected option', () => {
  const container = render(MySelect, {
    props: { options: [1, 2, 3], selected: 1 },
  });

  expect(container).toBeDefined();
  expect(container.toHTML()).toContain('<option value="1" selected>');

  container.setProp('selected', 2);
});

    Examples of correct code for this rule:

    it('lets me change the selected option', () => {
  const container = render(MySelect, {
    props: { options: [1, 2, 3], selected: 1 },
  });

  expect(container).toBeDefined();
  expect(container.toHTML()).toContain('<option value="1" selected>');

  container.setProp('selected', 2);

  expect(container.toHTML()).not.toContain('<option value="1" selected>');
  expect(container.toHTML()).toContain('<option value="2" selected>');
});

    Options

    interface Options {
  assertFunctionNames?: string[];
  additionalTestBlockFunctions?: string[];
}

    assertFunctionNames

    Names of functions treated as assertions. Patterns follow eslint-plugin-jest: * matches a dot-separated segment; ** matches zero or more segments. Default is ["expect"]. Special regex characters in names may need escaping (for example expect\\$).

    Examples of incorrect code with { "assertFunctionNames": ["expect"] }:

    {
  "jest/prefer-ending-with-an-expect": [
    "error",
    { "assertFunctionNames": ["expect"] }
  ]
}
    import { expectSaga } from 'redux-saga-test-plan';

test('returns sum', () => {
  expectSaga(addSaga, 1, 1).returns(2).run();
});

    Examples of correct code with { "assertFunctionNames": ["expect", "expectSaga"] }:

    {
  "jest/prefer-ending-with-an-expect": [
    "error",
    { "assertFunctionNames": ["expect", "expectSaga"] }
  ]
}
    import { expectSaga } from 'redux-saga-test-plan';

test('returns sum', () => {
  expectSaga(addSaga, 1, 1).returns(2).run();
});

    Examples of correct code for SuperTest with { "assertFunctionNames": ["expect", "request.**.expect"] }:

    {
  "jest/prefer-ending-with-an-expect": [
    "error",
    { "assertFunctionNames": ["expect", "request.**.expect"] }
  ]
}
    const request = require('supertest');
const express = require('express');

const app = express();

describe('GET /user', function () {
  it('responds with json', function (done) {
    doSomething();

    request(app).get('/user').expect('Content-Type', /json/).expect(200, done);
  });
});

    additionalTestBlockFunctions

    Extra function names treated like test / it wrappers so their callbacks are also required to end with an assertion.

    Examples of correct code with { "additionalTestBlockFunctions": ["each.test"] }:

    {
  "jest/prefer-ending-with-an-expect": [
    "error",
    { "additionalTestBlockFunctions": ["each.test"] }
  ]
}
    each([
  [2, 3],
  [1, 3],
]).test(
  'the selection can change from %d to %d',
  (firstSelection, secondSelection) => {
    const container = render(MySelect, {
      props: { options: [1, 2, 3], selected: firstSelection },
    });

    expect(container).toBeDefined();
    container.setProp('selected', secondSelection);

    expect(container.toHTML()).toContain(
      `<option value="${secondSelection}" selected>`,
    );
  },
);

    Original Documentation