diff --git a/gitindex/tree_test.go b/gitindex/tree_test.go
index 3b1ed14..eff31b3 100644
--- a/gitindex/tree_test.go
+++ b/gitindex/tree_test.go
@@ -39,7 +39,7 @@
 	}
 	script := `mkdir adir bdir
 cd adir
-git init
+git init -b master
 mkdir subdir
 echo acont > afile
 echo sub-cont > subdir/sub-file
@@ -50,7 +50,7 @@
 
 cd ..
 cd bdir
-git init
+git init -b master
 echo bcont > bfile
 git add bfile
 git config user.email "you@example.com"
@@ -300,7 +300,7 @@
 	}
 	script := `mkdir repo
 cd repo
-git init
+git init -b master
 mkdir subdir
 echo acont > afile
 echo sub-cont > subdir/sub-file