diff --git a/src/harness/harnessIO.ts b/src/harness/harnessIO.ts
index 584c5cc9a97..a1ab70a4f95 100644
--- a/src/harness/harnessIO.ts
+++ b/src/harness/harnessIO.ts
@@ -286,7 +286,7 @@ namespace Harness {
             return fileName;
         }
 
-        interface HarnessOptions {
+        export interface HarnessOptions {
             useCaseSensitiveFileNames?: boolean;
             includeBuiltFile?: string;
             baselineFile?: string;