base_config: Don't throw if loaded config file is empty

ts/test-node/app/base_config_test.ts

@@ -0,0 +1,71 @@
+// Copyright 2021 Signal Messenger, LLC
+// SPDX-License-Identifier: AGPL-3.0-only
+
+import { tmpdir } from 'os';
+import { writeFileSync, unlinkSync } from 'fs';
+
+import { v4 as generateGuid } from 'uuid';
+import { assert } from 'chai';
+
+import { start } from '../../../app/base_config';
+
+describe('base_config', () => {
+  let targetFile: string | undefined;
+
+  function getNewPath() {
+    return `${tmpdir()}/${generateGuid()}.txt`;
+  }
+
+  afterEach(() => {
+    if (targetFile) {
+      unlinkSync(targetFile);
+    }
+  });
+
+  it('does not throw if file is missing', () => {
+    const missingFile = getNewPath();
+    const { _getCachedValue } = start('test', missingFile);
+
+    assert.deepEqual(_getCachedValue(), Object.create(null));
+  });
+
+  it('successfully loads config file', () => {
+    targetFile = getNewPath();
+
+    const config = { a: 1, b: 2 };
+    writeFileSync(targetFile, JSON.stringify(config));
+    const { _getCachedValue } = start('test', targetFile);
+
+    assert.deepEqual(_getCachedValue(), config);
+  });
+
+  it('throws if file is malformed', () => {
+    targetFile = getNewPath();
+
+    writeFileSync(targetFile, '{{ malformed JSON');
+
+    const fileForClosure = targetFile;
+    assert.throws(() => start('test', fileForClosure));
+  });
+
+  it('does not throw if file is empty', () => {
+    targetFile = getNewPath();
+
+    writeFileSync(targetFile, '');
+
+    const { _getCachedValue } = start('test', targetFile);
+
+    assert.deepEqual(_getCachedValue(), Object.create(null));
+  });
+
+  it('does not throw if file is malformed, with allowMalformedOnStartup', () => {
+    targetFile = getNewPath();
+
+    writeFileSync(targetFile, '{{ malformed JSON');
+    const { _getCachedValue } = start('test', targetFile, {
+      allowMalformedOnStartup: true,
+    });
+
+    assert.deepEqual(_getCachedValue(), Object.create(null));
+  });
+});