diff --git a/tests/test.cpp b/tests/test.cpp
index 118ecb6cb..3d11410ed 100644
--- a/tests/test.cpp
+++ b/tests/test.cpp
@@ -505,7 +505,8 @@ void ScientificTest() {
   auto root = flatbuffers::GetRoot<float>(parser.builder_.GetBufferPointer());
   // root will point to the table, which is a 32bit vtable offset followed
   // by a float:
-  TEST_EQ(fabs(root[1] - 3.14159) < 0.001, true);
+  TEST_EQ(sizeof(flatbuffers::soffset_t) == 4 &&  // Test assumes 32bit offsets
+          fabs(root[1] - 3.14159) < 0.001, true);
 }
 
 void EnumStringsTest() {