[nrf fromtree] tests/fs: Replace flash_area_erase with flash_area_flatten

Test of file systems use flash_area_erase to erase device
to have a clear start for tests; switching to flash_area_flatten
allows them to do the same with devices that do not explicit
call to erase procedure before write.

Signed-off-by: Dominik Ermel <[email protected]>
(cherry picked from commit 1ae352a)

Author: de-nordic

tests/subsys/fs/fat_fs_api/src/test_fat_mkfs.c

@@ -45,7 +45,7 @@ static int wipe_partition(void)
 	}
 
 	TC_PRINT("Erasing %zu (0x%zx) bytes\n", pfa->fa_size, pfa->fa_size);
-	rc = flash_area_erase(pfa, 0, pfa->fa_size);
+	rc = flash_area_flatten(pfa, 0, pfa->fa_size);
 	(void)flash_area_close(pfa);
 
 	if (rc < 0) {

tests/subsys/fs/fcb/src/main.c

@@ -58,7 +58,7 @@ void test_fcb_wipe(void)
 	zassert_true(rc == 0, "flash area open call failure");
 
 	for (i = 0; i < ARRAY_SIZE(test_fcb_sector); i++) {
-		rc = flash_area_erase(fap, test_fcb_sector[i].fs_off,
+		rc = flash_area_flatten(fap, test_fcb_sector[i].fs_off,
 				      test_fcb_sector[i].fs_size);
 		zassert_true(rc == 0, "erase call failure");
 	}

tests/subsys/fs/littlefs/src/testfs_lfs.c

@@ -73,7 +73,7 @@ int testfs_lfs_wipe_partition(const struct fs_mount_t *mp)
 	}
 
 	TC_PRINT("Erasing %zu (0x%zx) bytes\n", pfa->fa_size, pfa->fa_size);
-	rc = flash_area_erase(pfa, 0, pfa->fa_size);
+	rc = flash_area_flatten(pfa, 0, pfa->fa_size);
 	(void)flash_area_close(pfa);
 
 	if (rc < 0) {

tests/subsys/fs/multi-fs/src/test_utils.c

@@ -31,6 +31,6 @@ void test_clear_flash(void)
 	rc = flash_area_open(TEST_PARTITION_ID, &fap);
 	zassert_equal(rc, 0, "Opening flash area for erase [%d]\n", rc);
 
-	rc = flash_area_erase(fap, 0, fap->fa_size);
+	rc = flash_area_flatten(fap, 0, fap->fa_size);
 	zassert_equal(rc, 0, "Erasing flash area [%d]\n", rc);
 }