Back to Repositories

Testing Text Difference Detection Implementation in Insomnia

This test suite validates the diff functionality in Insomnia’s sync module, focusing on block mapping and operation creation for text comparison. The tests ensure accurate handling of text differences and block-based comparison operations.

Test Coverage Overview

The test suite provides comprehensive coverage of the diff module’s core functionality.

Block map creation with specific hash generation
Basic text difference operations (COPY, INSERT)
Complex string comparison scenarios
Edge cases with varying block sizes

Implementation Analysis

The testing approach utilizes Jest’s describe/it pattern for structured unit testing. Tests employ a combination of simple and complex string inputs to verify the diff implementation’s accuracy.

Block-based text comparison testing
Hash-based block mapping validation
Operation sequence verification

Technical Details

Testing Framework: Vitest
Test Structure: Describe/It blocks
Assertion Method: expect().toEqual()
Test Focus: Internal methods (__internal) and public API (diff)
Block Size Parameters: Variable (2-3 characters)

Best Practices Demonstrated

The test suite exemplifies strong testing practices through clear organization and comprehensive validation.

Isolated test cases for distinct functionality
Clear input/output expectations
Progressive complexity in test scenarios
Thorough validation of internal utilities

kong/insomnia

packages/insomnia/src/sync/delta/__tests__/diff.test.ts

            
import { describe, expect, it } from 'vitest';

import { __internal, diff } from '../diff';

describe('diff()', () => {
  it('creates block map', () => {
    const result = __internal.getBlockMap('Hello World!!', 3);

    expect(result).toEqual({
      dbc2d1fed0dc37a70aea0f376958c802eddc0559: [
        {
          start: 0,
          len: 3,
          hash: 'dbc2d1fed0dc37a70aea0f376958c802eddc0559',
        },
      ],
      '263b8ac41bd2ffb775af535c54d8b0a0e6b9e743': [
        {
          start: 3,
          len: 3,
          hash: '263b8ac41bd2ffb775af535c54d8b0a0e6b9e743',
        },
      ],
      '3603dd999f7dd952041d3bdb27f74e511cfd6b2a': [
        {
          start: 6,
          len: 3,
          hash: '3603dd999f7dd952041d3bdb27f74e511cfd6b2a',
        },
      ],
      c20d168802bbae1c84f90b9b0495e0d918da3aea: [
        {
          start: 9,
          len: 3,
          hash: 'c20d168802bbae1c84f90b9b0495e0d918da3aea',
        },
      ],
      '0ab8318acaf6e678dd02e2b5c343ed41111b393d': [
        {
          start: 12,
          len: 1,
          hash: '0ab8318acaf6e678dd02e2b5c343ed41111b393d',
        },
      ],
    });
  });

  it('creates operations', () => {
    // hel|lo |Wor|ld!|!
    const result = diff('Hello World!!', 'Hello there World!!', 3);
    expect(result).toEqual([
      {
        type: 'COPY',
        start: 0,
        len: 6,
      },
      {
        type: 'INSERT',
        content: 'there ',
      },
      {
        type: 'COPY',
        start: 6,
        len: 7,
      },
    ]);
  });

  it('creates operations 2', () => {
    const result2 = diff(
      'Hello, this is a pretty long sentence about not much at all.',
      'Hello, this is a pretty short sentence.',
      2,
    );
    expect(result2).toEqual([
      {
        len: 24,
        start: 0,
        type: 'COPY',
      },
      {
        content: 'shor',
        type: 'INSERT',
      },
      {
        len: 2,
        start: 42,
        type: 'COPY',
      },
      {
        content: 's',
        type: 'INSERT',
      },
      {
        len: 7,
        start: 30,
        type: 'COPY',
      },
      {
        content: '.',
        type: 'INSERT',
      },
    ]);
  });
});