diff --git a/packages/server/src/integrations/tests/rest.spec.ts b/packages/server/src/integrations/tests/rest.spec.ts
index 144aefa576..ac5fa33148 100644
--- a/packages/server/src/integrations/tests/rest.spec.ts
+++ b/packages/server/src/integrations/tests/rest.spec.ts
@@ -655,6 +655,7 @@ describe("REST Integration", () => {
             }),
             get: (header: any) => {
               if (header === "content-type") return contentType
+              if (header === "content-length") return responseData.byteLength
               if (header === "content-disposition")
                 return `attachment; filename="${filename}"`
             },
@@ -700,6 +701,7 @@ describe("REST Integration", () => {
             }),
             get: (header: any) => {
               if (header === "content-type") return contentType
+              if (header === "content-length") return responseData.byteLength
               if (header === "content-disposition")
                 // eslint-disable-next-line no-useless-escape
                 return `attachment; filename="£ and ? rates.pdf"; filename*=UTF-8'\'%C2%A3%20and%20%E2%82%AC%20rates.pdf`