Generate mediaName for backed-up attachments

ts/test-electron/backup/backup_attachments_test.ts

@@ -0,0 +1,102 @@
+// Copyright 2024 Signal Messenger, LLC
+// SPDX-License-Identifier: AGPL-3.0-only
+
+import { assert } from 'chai';
+import * as sinon from 'sinon';
+
+import { getMediaNameForBackup } from '../../util/attachments/getMediaNameForBackup';
+import { IMAGE_PNG } from '../../types/MIME';
+import { sha256 } from '../../Crypto';
+import { DAY } from '../../util/durations';
+
+describe('getMediaNameForBackup', () => {
+  const TEST_HASH = sha256(Buffer.from('testattachmentdata'));
+  const TEST_HASH_BASE_64 =
+    // calculated as Buffer.from(TEST_HASH).toString('base64')
+    'ds5/U14lB2ziO90B7MldFTJUQdyw4qQ9y6Gnt9fmHL0=';
+
+  afterEach(function (this: Mocha.Context) {
+    sinon.restore();
+  });
+
+  it("should return base64 encoded plaintextHash if it's already been calculated", async () => {
+    assert.strictEqual(
+      await getMediaNameForBackup(
+        {
+          contentType: IMAGE_PNG,
+          size: 100,
+          plaintextHash: Buffer.from(TEST_HASH).toString('hex'),
+        },
+        'senderAci',
+        Date.now()
+      ),
+      TEST_HASH_BASE_64
+    );
+  });
+
+  it('should calculate hash from file on disk if plaintextHash has not yet been calculated', async () => {
+    const stubbedGetHashFromDisk = sinon
+      .stub()
+      .callsFake(async (_path: string) =>
+        Buffer.from(TEST_HASH).toString('hex')
+      );
+
+    const mediaName = await getMediaNameForBackup(
+      {
+        contentType: IMAGE_PNG,
+        size: 100,
+        path: 'path/to/file',
+      },
+      'senderAci',
+      Date.now(),
+      { getPlaintextHashForAttachmentOnDisk: stubbedGetHashFromDisk }
+    );
+
+    assert.strictEqual(stubbedGetHashFromDisk.callCount, 1);
+    assert.strictEqual(mediaName, TEST_HASH_BASE_64);
+  });
+
+  it('should return temporary identifier if attachment is undownloaded but in attachment tier', async () => {
+    const mediaName = await getMediaNameForBackup(
+      {
+        contentType: IMAGE_PNG,
+        size: 100,
+        cdnKey: 'cdnKey',
+      },
+      'senderAci',
+      Date.now()
+    );
+
+    assert.strictEqual(mediaName, 'senderAci_cdnKey');
+  });
+
+  it('should return temporary identifier if undownloaded attachment has temporary error', async () => {
+    const mediaName = await getMediaNameForBackup(
+      {
+        contentType: IMAGE_PNG,
+        size: 100,
+        cdnKey: 'cdnKey',
+        error: true,
+        key: 'attachmentkey',
+      },
+      'senderAci',
+      Date.now()
+    );
+
+    assert.strictEqual(mediaName, 'senderAci_cdnKey');
+  });
+
+  it('should return undefined if attachment is too old to be in attachment tier', async () => {
+    const mediaName = await getMediaNameForBackup(
+      {
+        contentType: IMAGE_PNG,
+        size: 100,
+        cdnKey: 'cdnKey',
+      },
+      'senderAci',
+      Date.now() - 31 * DAY
+    );
+
+    assert.strictEqual(mediaName, undefined);
+  });
+});