fix: remove new snapshot when existing snapshot matches (#76)

* chore: add failing test

* fix: remove new snapshot when existing snapshot matches

* fix: enable tests

* chore: use fs/promises in compare-pdf-to-snapshot

* Revert "chore: use fs/promises in compare-pdf-to-snapshot"

This reverts commit 04beef3.

CHANGELOG.md

@@ -1,5 +1,11 @@
 # Changelog
 
+## UNRELEASED
+
+### 🐛 Bug Fix
+
+- [PR#76](https://github.com/moshensky/pdf-visual-diff/pull/76) fix: remove new snapshot when existing snapshot matches
+
 ## 0.12.0 / 2024-09-26
 
 ### :tada: Enhancements

src/compare-pdf-to-snapshot.test.ts

@@ -1,16 +1,16 @@
 import { describe, it } from 'node:test'
 import * as assert from 'node:assert/strict'
+import { join } from 'node:path'
+import { existsSync, unlinkSync } from 'node:fs'
+import { unlink, readFile } from 'node:fs/promises'
 import { Jimp, JimpInstance } from 'jimp'
 import {
   comparePdfToSnapshot,
   snapshotsDirName,
   CompareOptions,
   RegionMask,
 } from './compare-pdf-to-snapshot'
-import { join } from 'path'
-import { existsSync, unlinkSync } from 'fs'
 import { compareImages } from './compare-images'
-import * as fs from 'fs/promises'
 import { Dpi } from './types'
 
 const testDataDir = join(__dirname, './test-data')
@@ -20,6 +20,14 @@ const singlePageSmallPdfPath = join(pdfs, 'single-page-small.pdf')
 const singlePagePdfPath = join(pdfs, 'single-page.pdf')
 const twoPagePdfPath = join(pdfs, 'two-page.pdf')
 
+async function removeIfExists(filePath: string): Promise<void> {
+  try {
+    await unlink(filePath)
+  } catch {
+    // File doesn't exist, no need to remove
+  }
+}
+
 describe('comparePdfToSnapshot()', () => {
   it('should create new snapshot, when one does not exists', () => {
     const snapshotName = 'single-page-small'
@@ -43,6 +51,23 @@ describe('comparePdfToSnapshot()', () => {
       assert.strictEqual(existsSync(snapshotNewPath), true, 'new is not created')
     }))
 
+  it('should remove diff and new snapshots when matches with reference snapshot', async () => {
+    const snapshotName = 'should-remove-diff-and-new'
+    const snapshotBase = join(__dirname, snapshotsDirName, snapshotName)
+    const snapshotPathDiff: `${string}.${string}` = `${snapshotBase}.diff.png`
+    const snapshotPathNew: `${string}.${string}` = `${snapshotBase}.new.png`
+
+    await removeIfExists(snapshotPathDiff)
+    await removeIfExists(snapshotPathNew)
+    await new Jimp({ width: 100, height: 100 }).write(snapshotPathDiff)
+    await new Jimp({ width: 100, height: 100 }).write(snapshotPathNew)
+
+    const isEqual = await comparePdfToSnapshot(singlePageSmallPdfPath, __dirname, snapshotName)
+    assert.strictEqual(isEqual, true)
+    assert.strictEqual(existsSync(snapshotPathDiff), false, 'Snapshot diff should not exists.')
+    assert.strictEqual(existsSync(snapshotPathNew), false, 'Snapshot new should not exists.')
+  })
+
   describe('should pass', () => {
     it('should pass', () =>
       comparePdfToSnapshot(twoPagePdfPath, __dirname, 'two-page-success').then((x) =>
@@ -75,7 +100,7 @@ describe('comparePdfToSnapshot()', () => {
         pdf2PngOptions: { dpi: Dpi.Low },
       }))
     it('two-page.pdf', () => testPdf2png(twoPage, 'two-page'))
-    it('two-page.pdf buffer', () => fs.readFile(twoPage).then((x) => testPdf2png(x, 'two-page')))
+    it('two-page.pdf buffer', () => readFile(twoPage).then((x) => testPdf2png(x, 'two-page')))
   })
 
   describe('maskRegions', () => {

src/compare-pdf-to-snapshot.ts

@@ -176,14 +176,19 @@ export function comparePdfToSnapshot(
     .then((images) =>
       compareImages(snapshotPath, images, restOpts).then((result) => {
         const diffSnapshotPath = path.join(dir, snapshotName + '.diff.png')
+        const newSnapshotPath = path.join(dir, snapshotName + '.new.png')
         if (result.equal) {
           if (existsSync(diffSnapshotPath)) {
             unlinkSync(diffSnapshotPath)
           }
+
+          if (existsSync(newSnapshotPath)) {
+            unlinkSync(newSnapshotPath)
+          }
+
           return true
         }
 
-        const newSnapshotPath = path.join(dir, snapshotName + '.new.png')
         return writeImages(newSnapshotPath)(images)
           .then(() => writeImages(diffSnapshotPath)(result.diffs.map((x) => x.diff)))
           .then(() => false)