new file mode 100755
--- /dev/null
+++ b/tests/test-notfound
@@ -0,0 +1,9 @@
+#!/bin/sh
+
+hg init
+
+echo "Is there an error message when trying to diff non-existing files?"
+hg diff not found
+
+echo "Is there an error message when trying to add non-existing files?"
+hg add not found

new file mode 100644
--- /dev/null
+++ b/tests/test-notfound.out
@@ -0,0 +1,9 @@
++ hg init
+Is there an error message when trying to diff non-existing files?
++ hg diff not found
+not: No such file or directory
+found: No such file or directory
+Is there an error message when trying to add non-existing files?
++ hg add not found
+not: No such file or directory
+found: No such file or directory