selftests/damon: add 'schemes' debugfs tests

This adds simple selftets for 'schemes' debugfs file of DAMON.

Link: https://lkml.kernel.org/r/20211001125604.29660-7-sj@kernel.orgSigned-off-by: SeongJae Park <sj@kernel.org>
Cc: Amit Shah <amit@kernel.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Rienjes <rientjes@google.com>
Cc: David Woodhouse <dwmw@amazon.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Leonard Foerster <foersleo@amazon.de>
Cc: Marco Elver <elver@google.com>
Cc: Markus Boehme <markubo@amazon.de>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

tools/testing/selftests/damon/debugfs_attrs.sh

@@ -57,6 +57,19 @@ test_write_fail "$file" "1 2 3 5 4" "$orig_content" \
 test_content "$file" "$orig_content" "1 2 3 4 5" "successfully written"
 echo "$orig_content" > "$file"
 
+# Test schemes file
+# =================
+
+file="$DBGFS/schemes"
+orig_content=$(cat "$file")
+
+test_write_succ "$file" "1 2 3 4 5 6 4" \
+	"$orig_content" "valid input"
+test_write_fail "$file" "1 2
+3 4 5 6 3" "$orig_content" "multi lines"
+test_write_succ "$file" "" "$orig_content" "disabling"
+echo "$orig_content" > "$file"
+
 # Test target_ids file
 # ====================