diff --git a/test/edit.t b/test/edit.t
index 25d0694f3..9af04cee4 100755
--- a/test/edit.t
+++ b/test/edit.t
@@ -41,7 +41,7 @@ class TestTaskEdit(TestCase):
         self.t = Task()
 
         # Workaround to always assume changes were introduced via "task edit"
-        self.editor = mkstemp_exec("echo '' >> $1\n")
+        self.editor = mkstemp_exec(b"echo '' >> $1\n")
 
         self.t.env["VISUAL"] = self.editor
 
diff --git a/test/tw-20.t b/test/tw-20.t
index e6d956ca5..217184d47 100755
--- a/test/tw-20.t
+++ b/test/tw-20.t
@@ -44,7 +44,7 @@ class TestBug20(TestCase):
         self.t = Task()
 
         # Workaround to always assume changes were introduced via "task edit"
-        self.editor = mkstemp_exec("echo '' >> $1\n")
+        self.editor = mkstemp_exec(b"echo '' >> $1\n")
 
         self.t.env["VISUAL"] = self.editor