[PATCH] Fix mountpoint test failure in build chroots.

[Chris Hofstaedtler <zeha@debian.org>]

From: Mark Hindley <mark@hindley.org.uk>

The test assumed that / was a mountpoint. This is not always the case, for
example in pbuilder/cowbuilder chroots. So use / if findmnt verifies it is a
mountpoint, otherwise use the first mountpoint found. Skip the test if no
mountpoints are found.

Signed-off-by: Mark Hindley <mark@hindley.org.uk>
---
 tests/expected/misc/mountpoint-default  |  2 +-
 tests/expected/misc/mountpoint-nofollow |  2 +-
 tests/ts/misc/mountpoint                | 15 +++++++++++----
 3 files changed, 13 insertions(+), 6 deletions(-)

diff --git a/tests/expected/misc/mountpoint-default b/tests/expected/misc/mountpoint-default
index 9a7ac6ab3..ca7505538 100644
--- a/tests/expected/misc/mountpoint-default
+++ b/tests/expected/misc/mountpoint-default
@@ -1,2 +1,2 @@
-./symlink-to-root is a mountpoint
+./symlink-to-mountpoint is a mountpoint
 0
diff --git a/tests/expected/misc/mountpoint-nofollow b/tests/expected/misc/mountpoint-nofollow
index 1ba174959..03d2b5da8 100644
--- a/tests/expected/misc/mountpoint-nofollow
+++ b/tests/expected/misc/mountpoint-nofollow
@@ -1,2 +1,2 @@
-./symlink-to-root is not a mountpoint
+./symlink-to-mountpoint is not a mountpoint
 1
diff --git a/tests/ts/misc/mountpoint b/tests/ts/misc/mountpoint
index 1b391c3bf..e52ccb28f 100755
--- a/tests/ts/misc/mountpoint
+++ b/tests/ts/misc/mountpoint
@@ -7,16 +7,23 @@ TS_DESC="mountpoint"
 ts_init "$*"
 
 ts_check_test_command "$TS_CMD_MOUNTPOINT"
+ts_check_test_command "$TS_CMD_FINDMNT"
 
-ln -s / ./symlink-to-root
+# / is not always a mountpoint (chroots etc.), so check if it is and otherwise
+# fallback to the first available mountpoint.
+FIRST_MOUNTPOINT=$($TS_CMD_FINDMNT -no TARGET / || $TS_CMD_FINDMNT -fno TARGET)
+
+[ -z "$FIRST_MOUNTPOINT" ] && ts_skip "no mountpoint found for symlink tests"
+
+ln -s $FIRST_MOUNTPOINT ./symlink-to-mountpoint
 
 ts_init_subtest "default"
-$TS_CMD_MOUNTPOINT ./symlink-to-root >> $TS_OUTPUT 2>> $TS_ERRLOG
+$TS_CMD_MOUNTPOINT ./symlink-to-mountpoint >> $TS_OUTPUT 2>> $TS_ERRLOG
 echo $? >> $TS_OUTPUT 2>> $TS_ERRLOG
 ts_finalize_subtest
 
 ts_init_subtest "nofollow"
-$TS_CMD_MOUNTPOINT --nofollow ./symlink-to-root >> $TS_OUTPUT 2>> $TS_ERRLOG
+$TS_CMD_MOUNTPOINT --nofollow ./symlink-to-mountpoint >> $TS_OUTPUT 2>> $TS_ERRLOG
 echo $? >> $TS_OUTPUT 2>> $TS_ERRLOG
 ts_finalize_subtest
 
@@ -25,5 +32,5 @@ $TS_CMD_MOUNTPOINT --devno --nofollow / >> $TS_OUTPUT 2>> $TS_ERRLOG
 echo $? >> $TS_OUTPUT 2>> $TS_ERRLOG
 ts_finalize_subtest
 
-rm -f ./symlink-to-root
+rm -f ./symlink-to-mountpoint
 ts_finalize
-- 
2.27.0