Back to Repositories

Validating Core API Exports and Types in Preact

This test suite validates the core exports and API functionality of the Preact library. It ensures that all essential Preact functions and components are properly exposed and maintain their expected types and behaviors.

Test Coverage Overview

The test suite provides comprehensive coverage of Preact’s public API exports, verifying the availability and type correctness of fundamental functions and components.

Tests all core Preact exports including createElement, Component, Fragment, and render
Validates function types and object existence
Covers utility functions like createRef and toChildArray
Ensures API consistency and reliability

Implementation Analysis

The testing approach utilizes Jest and Chai assertion library to verify the type and existence of each exported member. The implementation follows a structured pattern of individual assertions for each API component, ensuring precise type checking and availability verification.

Uses Chai’s expect syntax for assertions
Implements type checking via .to.be.a(‘function’)
Validates object existence with .to.exist

Technical Details

Testing Framework: Jest
Assertion Library: Chai
Test Type: Unit Testing
File Location: test/shared/exports.test.js
Import Strategy: Named imports from root

Best Practices Demonstrated

The test file demonstrates several testing best practices for JavaScript library API validation. It employs clear test organization with descriptive test blocks and granular assertions for each export.

Isolated test scope for exports verification
Consistent assertion patterns
Clear test descriptions
Comprehensive API surface coverage

preactjs/preact

test/shared/exports.test.js

            
import {
	createElement,
	h,
	createContext,
	Component,
	Fragment,
	render,
	hydrate,
	cloneElement,
	options,
	createRef,
	toChildArray,
	isValidElement
} from '../../';
import { expect } from 'chai';

describe('preact', () => {
	it('should be available as named exports', () => {
		expect(h).to.be.a('function');
		expect(createElement).to.be.a('function');
		expect(Component).to.be.a('function');
		expect(Fragment).to.exist;
		expect(render).to.be.a('function');
		expect(hydrate).to.be.a('function');
		expect(cloneElement).to.be.a('function');
		expect(createContext).to.be.a('function');
		expect(options).to.exist.and.be.an('object');
		expect(createRef).to.be.a('function');
		expect(isValidElement).to.be.a('function');
		expect(toChildArray).to.be.a('function');
	});
});