Switch to tty1 multi-times in ro snapshot

This may fix some sporadic failures during booting
read-only snapshot at snapper rollback stage.

See: https://progress.opensuse.org/issues/40154

lib/migration.pm

@@ -35,6 +35,7 @@ our @EXPORT = qw(
   record_disk_info
   check_rollback_system
   reset_consoles_tty
+  boot_into_ro_snapshot
 );
 
 sub setup_sle {
@@ -157,4 +158,26 @@ sub reset_consoles_tty {
     reset_consoles;
 }
 
+# Assert read-only snapshot before migrated
+# Assert screen 'linux-login' with 200s
+# Workaround known issue: bsc#980337
+# In this case try to select tty1 with multi-times then select root console
+sub boot_into_ro_snapshot {
+    if (!check_screen('linux-login', 200)) {
+        record_soft_failure 'bsc#980337';
+        my $retries = 10;
+        for my $i (0 .. $retries) {
+            send_key "ctrl-alt-f1";
+            if (check_screen('tty1-selected', 5)) {
+                last;
+            }
+            else {
+                record_info('not in tty1', 'switch to tty1 failed', result => 'softfail');
+            }
+            die "Boot into read-only snapshot failed over 5 minutes, considering a product issue" if $i == $retries;
+            sleep 10;
+        }
+    }
+}
+
 1;

tests/boot/snapper_rollback.pm

@@ -14,19 +14,12 @@ use base "consoletest";
 use testapi;
 use utils;
 use strict;
-use migration 'check_rollback_system';
+use migration qw(check_rollback_system boot_into_ro_snapshot);
 
 sub run {
     my ($self) = @_;
 
-    # assert the we are on a ro snapshot.
-    # assert_screen 'linux-login', 200;
-    # workaround known issue: bsc#980337
-    if (!check_screen('linux-login', 200)) {
-        record_soft_failure 'bsc#980337';
-        send_key "ctrl-alt-f1";
-        assert_screen 'tty1-selected';
-    }
+    boot_into_ro_snapshot;
     select_console 'root-console';
     # 1)
     script_run('touch NOWRITE;test ! -f NOWRITE', 0);

tests/migration/sle12_online_migration/snapper_rollback.pm

@@ -15,21 +15,12 @@ use strict;
 use testapi;
 use power_action_utils 'power_action';
 use version_utils 'is_desktop_installed';
-use migration 'check_rollback_system';
+use migration qw(check_rollback_system boot_into_ro_snapshot);
 
 sub run {
     my ($self) = @_;
 
-    # login to before online migration snapshot
-    # tty would not appear quite often after booting snapshot
-    # it is a known bug bsc#980337
-    # in this case select tty1 first then select root console
-    if (!check_screen('linux-login', 200)) {
-        record_soft_failure 'bsc#980337';
-        send_key "ctrl-alt-f1";
-        assert_screen 'tty1-selected';
-    }
-
+    boot_into_ro_snapshot;
     select_console 'root-console';
     script_run "snapper rollback";