test: fs: Add filesystem integrity checks

We need to make sure that file writes,file creation, etc. are properly
performed and do not corrupt the filesystem.
To help with this, introduce the assert_fs_integrity() function that
executes the appropriate fsck tool. It should be called at the end of any
test that modify the content/organization of the filesystem.
Currently only supports FATs and EXT4.

Signed-off-by: Jean-Jacques Hiblot <jjhiblot@ti.com>
Reviewed-by: Tom Rini <trini@konsulko.com>

test/py/tests/test_fs/fstest_helpers.py

@@ -0,0 +1,15 @@
+# SPDX-License-Identifier:      GPL-2.0+
+# Copyright (c) 2019, Texas Instrument
+# Author: JJ Hiblot <jjhiblot@ti.com>
+#
+
+from subprocess import check_call, CalledProcessError
+
+def assert_fs_integrity(fs_type, fs_img):
+    try:
+        if fs_type == 'ext4':
+            check_call('fsck.ext4 -n -f %s' % fs_img, shell=True)
+        if fs_type == 'fat':
+            check_call('fsck.fat -n %s' % fs_img, shell=True)
+    except CalledProcessError:
+        raise