Timeline: repair oldest/newest metrics if we fetch nothing

ts/test-node/util/getTextWithMentions_test.ts

@@ -0,0 +1,45 @@
+// Copyright 2020 Signal Messenger, LLC
+// SPDX-License-Identifier: AGPL-3.0-only
+
+import { expect } from 'chai';
+import { getTextWithMentions } from '../../util/getTextWithMentions';
+
+describe('getTextWithMentions', () => {
+  describe('given mention replacements', () => {
+    it('replaces them', () => {
+      const bodyRanges = [
+        {
+          length: 1,
+          mentionUuid: 'abcdef',
+          replacementText: 'fred',
+          start: 4,
+        },
+      ];
+      const text = "Hey \uFFFC, I'm here";
+      expect(getTextWithMentions(bodyRanges, text)).to.eql(
+        "Hey @fred, I'm here"
+      );
+    });
+
+    it('sorts them to go from back to front', () => {
+      const bodyRanges = [
+        {
+          length: 1,
+          mentionUuid: 'blarg',
+          replacementText: 'jerry',
+          start: 0,
+        },
+        {
+          length: 1,
+          mentionUuid: 'abcdef',
+          replacementText: 'fred',
+          start: 7,
+        },
+      ];
+      const text = "\uFFFC says \uFFFC, I'm here";
+      expect(getTextWithMentions(bodyRanges, text)).to.eql(
+        "@jerry says @fred, I'm here"
+      );
+    });
+  });
+});