diff --git a/src/Tests/TestUtils.cs b/src/Tests/TestUtils.cs
index 618a0abb..d66c879d 100644
--- a/src/Tests/TestUtils.cs
+++ b/src/Tests/TestUtils.cs
@@ -85,7 +85,7 @@ public static Stream CreateOutputStream(string expectedPath)
 
                     return new FileStream(
                         outputPath,
-                        FileMode.Create,
+                        FileMode.CreateNew,
                         FileAccess.ReadWrite,
                         FileShare.Read,
                         4096,