diff --git a/cpp/core/internal/offline_frames_validator_test.cc b/cpp/core/internal/offline_frames_validator_test.cc
index e659e86f..339964f4 100644
--- a/cpp/core/internal/offline_frames_validator_test.cc
+++ b/cpp/core/internal/offline_frames_validator_test.cc
@@ -192,7 +192,9 @@ TEST(OfflineFramesValidatorTest, ValidatesAsOkWithValidPayloadTransferFrame) {
   PayloadTransferFrame::PayloadChunk chunk;
   header.set_id(12345);
   header.set_type(PayloadTransferFrame::PayloadHeader::BYTES);
-  header.set_total_size(1024);
+  // Sending files larger than 2gb was previously broken (see cl/372382338).
+  // This tests a file larger than int max.
+  header.set_total_size(3e10);
   chunk.set_body("payload data");
   chunk.set_offset(150);
   chunk.set_flags(1);