t.expect.notContains Method

Assertion method. Succeeds if x does not contain y.

t.expect(x).notContains(y, message, options)  → this | Promise<unknown>
Parameter Type Description
x String | Array | Object The first operand of the assertion (see the x parameter).
y Any type The second operand of the assertion.
message (optional) String Custom assertion error message.
options (optional) Object See Options.


await t
    .expect('foo bar').notContains('baz', 'string does not contain a substring')
    .expect([1, 2, 3]).notContains(4, 'array does not contain a value')
    .expect({ foo: 'bar', hello: 'universe' }).notContains({ buzz: 'abc' }, 'object does not contain a property');
import { ClientFunction } from 'testcafe';


test('Check location', async t => {
    const getLocation = ClientFunction(() => document.location.href.toString());

    await t.expect(getLocation()).notContains('devexpress.com');

the x parameter

x is the first operand of the assertion.

If the first operand contains a selector property, a client function, or any other compatible function, the assertion becomes subject to the Smart Assertion Query Mechanism.

Different assertion methods accept different arguments. Make sure that your operands belong to compatible data types.



Type: Number

If an assertion’s first operand contains a compatible function, the assertion is subject to the Smart Assertion Query Mechanism.

If such an assertion fails, TestCafe executes it again until it meets either of the following criteria:

  • The assertion succeeds.
  • The assertion timeout elapses.
await t.expect(Selector('h1').innerText).eql('text', 'check element text', { timeout: 20000 });

To set the timeout for the entire test run, define the assertion timeout in one of the following ways:


The timeout option applies to built-in TestCafe assertion methods. Use the t.wait() method to specify timeouts for third-party assertion methods (assert or chai).


TestCafe awaits Promises from compatible asynchronous functions. If your assertion includes a custom function that returns a Promise, the assertion fails.

When you create assertions, avoid the use of custom functions that return a Promise. If you can’t work around this limitation, use the allowUnawaitedPromise option:

await t
        .expect(new Promise(resolve => setTimeout(resolve, 100)))
        .ok('received a promise', { allowUnawaitedPromise: true });