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Testing Object Difference Detection Utility in GatsbyJS

This test suite validates the getDiff utility function in Gatsby Recipes, which compares two objects and generates a line-by-line difference with color coding. The tests ensure proper difference detection between object structures and verify the output formatting with ANSI color codes.

Test Coverage Overview

The test coverage focuses on the core functionality of the getDiff utility, verifying its ability to compare and highlight differences between JavaScript objects.

Tests basic object comparison with different key structures
Validates color-coded output generation
Verifies asynchronous operation handling

Implementation Analysis

The testing approach utilizes Jest’s asynchronous testing capabilities with async/await syntax for handling the getDiff function’s promises. The implementation follows a simple arrange-act-assert pattern, comparing two object literals with different structures.

Uses async/await for promise handling
Implements Jest’s expect assertions
Employs object literal test fixtures

Technical Details

Testing Framework: Jest
Test Pattern: Unit test
Assertion Style: expect().toBeTruthy()
Test Data: Simple JavaScript objects
Async Pattern: Promise-based testing

Best Practices Demonstrated

The test demonstrates clean and focused unit testing practices with clear separation of test data and assertions. It follows modern JavaScript testing conventions with proper async handling and clear test descriptions.

Clear test case isolation
Descriptive test naming
Proper async/await usage
Simple and focused test scope

gatsbyjs/gatsby

deprecated-packages/gatsby-recipes/src/providers/utils/get-diff.test.js

            
import getDiff from "./get-diff"

const oldValue = { a: `hi` }
const newValue = { b: `hi` }

it(`diffs values by line with color codes`, async () => {
  const result = await getDiff(oldValue, newValue)
  expect(result).toBeTruthy()
})