Migrate gr-diff-highlight_test from js to ts

Compare against patchset 1 for a proper js<->ts diff.

Release-Notes: skip
Google-Bug-Id: n/a
Change-Id: Ia8f1ca4739edced49e3a7e5c9f7e4b6c214b2db0
diff --git a/polygerrit-ui/app/test/test-data-generators.ts b/polygerrit-ui/app/test/test-data-generators.ts
index cc292e6..2fffc9a 100644
--- a/polygerrit-ui/app/test/test-data-generators.ts
+++ b/polygerrit-ui/app/test/test-data-generators.ts
@@ -33,6 +33,7 @@
   CommentInfo,
   CommentLinkInfo,
   CommentLinks,
+  CommentRange,
   CommitId,
   CommitInfo,
   ConfigInfo,
@@ -652,6 +653,15 @@
   };
 }
 
+export function createRange(): CommentRange {
+  return {
+    start_line: 1,
+    start_character: 0,
+    end_line: 1,
+    end_character: 1,
+  };
+}
+
 export function createComment(
   extra: Partial<CommentInfo | DraftInfo> = {}
 ): CommentInfo {