Windows: mark downloads as "from the internet"

ts/test/util/windowsZoneIdentifier_test.ts

@@ -0,0 +1,64 @@
+import { assert } from 'chai';
+import * as path from 'path';
+import * as os from 'os';
+import * as fs from 'fs';
+import * as fse from 'fs-extra';
+import * as Sinon from 'sinon';
+import { assertRejects } from '../helpers';
+
+import { writeWindowsZoneIdentifier } from '../../util/windowsZoneIdentifier';
+
+describe('writeWindowsZoneIdentifier', () => {
+  before(function thisNeeded() {
+    if (process.platform !== 'win32') {
+      this.skip();
+    }
+  });
+
+  beforeEach(async function thisNeeded() {
+    this.sandbox = Sinon.createSandbox();
+    this.tmpdir = await fs.promises.mkdtemp(
+      path.join(os.tmpdir(), 'signal-test-')
+    );
+  });
+
+  afterEach(async function thisNeeded() {
+    this.sandbox.restore();
+    await fse.remove(this.tmpdir);
+  });
+
+  it('writes zone transfer ID 3 (internet) to the Zone.Identifier file', async function thisNeeded() {
+    const file = path.join(this.tmpdir, 'file.txt');
+    await fse.outputFile(file, 'hello');
+
+    await writeWindowsZoneIdentifier(file);
+
+    assert.strictEqual(
+      await fs.promises.readFile(`${file}:Zone.Identifier`, 'utf8'),
+      '[ZoneTransfer]\r\nZoneId=3'
+    );
+  });
+
+  it('fails if there is an existing Zone.Identifier file', async function thisNeeded() {
+    const file = path.join(this.tmpdir, 'file.txt');
+    await fse.outputFile(file, 'hello');
+    await fs.promises.writeFile(`${file}:Zone.Identifier`, '# already here');
+
+    await assertRejects(() => writeWindowsZoneIdentifier(file));
+  });
+
+  it('fails if the original file does not exist', async function thisNeeded() {
+    const file = path.join(this.tmpdir, 'file-never-created.txt');
+
+    await assertRejects(() => writeWindowsZoneIdentifier(file));
+  });
+
+  it('fails if not on Windows', async function thisNeeded() {
+    this.sandbox.stub(process, 'platform').get(() => 'darwin');
+
+    const file = path.join(this.tmpdir, 'file.txt');
+    await fse.outputFile(file, 'hello');
+
+    await assertRejects(() => writeWindowsZoneIdentifier(file));
+  });
+});