diff --git a/src/azure_devtools/scenario_tests/base.py b/src/azure_devtools/scenario_tests/base.py
index 81d90f9..29c7d29 100644
--- a/src/azure_devtools/scenario_tests/base.py
+++ b/src/azure_devtools/scenario_tests/base.py
@@ -37,7 +37,10 @@ def create_temp_file(self, size_kb, full_random=False):
 
         with open(path, mode='r+b') as f:
             if full_random:
-                chunk = os.urandom(1024)
+                chunk = bytearray("".join(chr(int((126 - 32) \
+                                        * (ord(_) if isinstance(_, str) else _) \
+                                        / 255 + 32)) for _ in os.urandom(1024)),
+                                  'utf-8')
             else:
                 chunk = bytearray([0] * 1024)
             for _ in range(size_kb):