selftests/efivarfs: add empty file creation test

Signed-off-by: NJeremy Kerr <jk@ozlabs.org>
Cc: Matt Fleming <matt.fleming@intel.com>
Cc: Lingzhu Xiang <lxiang@redhat.com>
Cc: Dave Young <dyoung@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

tools/testing/selftests/efivarfs/efivarfs.sh

@@ -58,6 +58,18 @@ test_create()
 	fi
 }
 
+test_create_empty()
+{
+	local file=$efivarfs_mount/$FUNCNAME-$test_guid
+
+	: > $file
+
+	if [ ! -e $file ]; then
+		echo "$file can not be created without writing" >&2
+		exit 1
+	fi
+}
+
 test_delete()
 {
 	local attrs='\x07\x00\x00\x00'
@@ -112,6 +124,7 @@ check_prereqs
 rc=0
 
 run_test test_create
+run_test test_create_empty
 run_test test_delete
 run_test test_zero_size_delete
 run_test test_open_unlink