import * as fs from 'fs/promises';
import * as path from 'path';
import { DiffManager } from '../src/diff/DiffManager';
import type { DiffChange } from '../src/types';
describe('DiffManager', () => {
describe('computeDiff (via any)', () => {
it('merges remove+add blocks into modified with correct line numbers', () => {
const dm = new DiffManager();
const oldContent = [
'a',
'b',
'c',
'd',
].join('\n');
const newContent = [
'a',
'b2',
'c2',
'd',
].join('\n');
const changes: ReturnType<any> = (dm as any).computeDiff(oldContent, newContent, 'dummy.ts');
// Expect a single modified block replacing lines 2-3 with 2-3
const modified = changes.find((c: DiffChange) => c.type === 'modified');
expect(modified).toBeTruthy();
expect(modified!.oldStart).toBe(2);
expect(modified!.oldEnd).toBe(3);
expect(modified!.newStart).toBe(2);
expect(modified!.newEnd).toBe(3);
expect(modified!.content).toBe(['b2', 'c2'].join('\n'));
});
});
describe('applyDiff', () => {
it('applies added, removed, and modified changes correctly', () => {
const dm = new DiffManager();
const original = ['line1', 'line2', 'line3', 'line4'].join('\n');
const changes: DiffChange[] = [
// remove line2
{ type: 'removed', oldStart: 2, oldEnd: 2, content: 'line2' },
// modify line3 -> x3
{ type: 'modified', oldStart: 3, oldEnd: 3, newStart: 3, newEnd: 3, content: 'x3' },
// add a line before end
{ type: 'added', newStart: 4, newEnd: 4, content: 'inserted' },
];
const result = dm.applyDiff(original, changes);
expect(result.split('\n')).toEqual(['line1', 'x3', 'inserted', 'line4']);
});
});
describe('generateContextualDiff', () => {
const tmpDir = path.join(process.cwd(), 'tests', 'tmp');
const filePath = path.join(tmpDir, 'context.txt');
beforeAll(async () => {
await fs.mkdir(tmpDir, { recursive: true });
});
it('includes surrounding context lines for added/removed/modified', async () => {
const dm = new DiffManager();
const oldContent = ['A', 'B', 'C', 'D', 'E', 'F'].join('\n');
const newContent = ['A', 'B', 'X', 'Y', 'E', 'F'].join('\n');
// snapshot from old content
dm.createSnapshotFromContent(filePath, oldContent);
// write new content to file so method can read it
await fs.writeFile(filePath, newContent, 'utf8');
const contextual = await dm.generateContextualDiff(filePath, 1);
expect(Array.isArray(contextual)).toBe(true);
// Should have at least one modified block containing context around X,Y
const mod = contextual.find((c) => c.type === 'modified');
expect(mod).toBeTruthy();
expect(mod!.content).toContain('B');
expect(mod!.content).toContain('X');
expect(mod!.content).toContain('Y');
expect(mod!.content).toContain('E');
});
});
});
