testing-patterns

name	testing-patterns
description	Jest testing patterns, factory functions, mocking strategies, and TDD workflow. Use when writing unit tests, creating test factories, or following TDD red-green-refactor cycle.
type	skill
created	2026-02-27T00:00:00.000Z
domain	software-development
category	testing
risk	unknown
source	community
tags	["skill","software-development","testing"]

Testing Patterns and Utilities

Testing Philosophy

Test-Driven Development (TDD):

• Write failing test FIRST
• Implement minimal code to pass
• Refactor after green
• Never write production code without a failing test

Behavior-Driven Testing:

• Test behavior, not implementation
• Focus on public APIs and business requirements
• Avoid testing implementation details
• Use descriptive test names that describe behavior

Factory Pattern:

• Create getMockX(overrides?: Partial<X>) functions
• Provide sensible defaults
• Allow overriding specific properties
• Keep tests DRY and maintainable

Test Utilities

Custom Render Function

Create a custom render that wraps components with required providers:

// src/utils/testUtils.tsx
import { render } from '@testing-library/react-native';
import { ThemeProvider } from './theme';

export const renderWithTheme = (ui: React.ReactElement) => {
  return render(
    <ThemeProvider>{ui}</ThemeProvider>
  );
};

Usage:

import { renderWithTheme } from 'utils/testUtils';
import { screen } from '@testing-library/react-native';

it('should render component',  {
  ();
  (screen.()).();
});