Implementation:DevExpress Testcafe Assertions TypeDefs

Knowledge Sources	DevExpress_Testcafe TestCafe Assertions
Domains	Type_Definitions, Testing, Assertions
Last Updated	2026-02-12 12:00 GMT

Overview

Concrete TypeScript type declarations for TestCafe's Assertion interface providing all assertion methods available on the t.expect() chain.

Description

This file defines the AssertionOptions interface (with timeout and allowUnawaitedPromise) and the generic Assertion<E> interface that provides methods: eql, notEql, ok, notOk, contains, notContains, typeOf, notTypeOf, gt, gte, lt, lte, within, notWithin, and match/notMatch. Each method returns TestControllerPromise for chaining and accepts optional AssertionOptions.

Usage

These types power TypeScript IntelliSense for t.expect(value).eql(expected) assertion chains in test files.

Code Reference

Source Location

• Repository: DevExpress_Testcafe
• File: ts-defs-src/test-api/assertions.d.ts
• Lines: 1-261

Signature

interface AssertionOptions {
    timeout?: number;
    allowUnawaitedPromise?: boolean;
}

interface Assertion<E> {
    eql(expected: E, message?: string, opts?: AssertionOptions): TestControllerPromise;
    notEql(unexpected: E, message?: string, opts?: AssertionOptions): TestControllerPromise;
    ok(message?: string, opts?: AssertionOptions): TestControllerPromise;
    notOk(message?: string, opts?: AssertionOptions): TestControllerPromise;
    contains(expected: any, message?: string, opts?: AssertionOptions): TestControllerPromise;
    notContains(unexpected: any, message?: string, opts?: AssertionOptions): TestControllerPromise;
    typeOf(typeName: string, message?: string, opts?: AssertionOptions): TestControllerPromise;
    notTypeOf(typeName: string, message?: string, opts?: AssertionOptions): TestControllerPromise;
    gt(expected: number, message?: string, opts?: AssertionOptions): TestControllerPromise;
    gte(expected: number, message?: string, opts?: AssertionOptions): TestControllerPromise;
    lt(expected: number, message?: string, opts?: AssertionOptions): TestControllerPromise;
    lte(expected: number, message?: string, opts?: AssertionOptions): TestControllerPromise;
    within(start: number, finish: number, message?: string, opts?: AssertionOptions): TestControllerPromise;
    notWithin(start: number, finish: number, message?: string, opts?: AssertionOptions): TestControllerPromise;
    match(re: RegExp, message?: string, opts?: AssertionOptions): TestControllerPromise;
    notMatch(re: RegExp, message?: string, opts?: AssertionOptions): TestControllerPromise;
}

Import

// Automatically available in TestCafe TypeScript test files

I/O Contract

Inputs

Name	Type	Required	Description
actual	E (generic)	Yes	Value to assert (from t.expect(actual))
expected	E	Yes	Expected value for comparison assertions
message	string	No	Custom error message on failure
opts	AssertionOptions	No	Timeout and allowUnawaitedPromise options

Outputs

Name	Type	Description
TestControllerPromise	TestController & Promise	Enables chaining after assertions

Usage Examples

import { Selector } from 'testcafe';

fixture('Assertions').page('https://example.com');

test('Assertion methods', async (t: TestController) => {
    // Equality
    await t.expect(Selector('h1').textContent).eql('Welcome');
    await t.expect(Selector('.count').textContent).notEql('0');

    // Truthiness
    await t.expect(Selector('#element').exists).ok();
    await t.expect(Selector('.error').exists).notOk();

    // Contains
    await t.expect(Selector('p').textContent).contains('important');

    // Numeric comparisons
    await t.expect(Selector('.items').count).gt(0);
    await t.expect(Selector('.items').count).lte(100);
    await t.expect(Selector('.progress').textContent).within(0, 100);

    // Regex matching
    await t.expect(Selector('.email').textContent).match(/\w+@\w+\.\w+/);

    // With timeout option
    await t.expect(Selector('.loading').exists).notOk('Still loading', { timeout: 10000 });
});

Related Pages

• Environment:DevExpress_Testcafe_Node_Runtime