diff --git a/t/t5100/.gitattributes b/t/t5100/.gitattributes
new file mode 100644
index 000000000..c93f5142f
--- /dev/null
+++ b/t/t5100/.gitattributes
@@ -0,0 +1,4 @@
+msg*	encoding=UTF-8
+info*	encoding=UTF-8
+rfc2047-info-*	encoding=UTF-8
+sample.mbox	encoding=UTF-8