javascript / beginner
Snippet
Unit Testing Utility Functions with Jest Assertions
Testing ensures individual helper functions behave predictably before using them in Next.js pages. This snippet uses Jest to test a price formatting utility function.
snippet.js
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// utils/format.test.jsimport { formatPrice } from './format';test('formats numeric amounts into USD currency strings', () => {const result = formatPrice(49.99);expect(result).toBe('$49.99');});
nextjs
Breakdown
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import { formatPrice } from './format';
Imports the target utility function to test.
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test('formats numeric amounts into USD currency strings', () => {
Defines a new test case with a descriptive title and runner callback.
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const result = formatPrice(49.99);
Calls the helper function with sample input data.
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expect(result).toBe('$49.99');
Asserts that the actual function output matches the expected currency string.