check: run auto test group by default

Everyone who starts using fstests runs "check" without parameters,
and then has problems with it running dangerous tests. most people
just want fstests to act as a regression test suite, not a fuzzer or
exercise known crash conditions. Hence make the default behaviour to
be "run the auto group" rather than "run every test".

To enable people to run all tests easily (if they really want to)
add a special group keyword named "all". This wildcard will trigger
selecting all the tests in fstests as per the original "check
without parameters" behaviour.

Signed-Off-By: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Eric Sandeen <sandeen@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Eryu Guan <guaneryu@gmail.com>

check

@@ -102,6 +102,8 @@ a test file name match pattern (e.g. xfs/*).
 group argument is either a name of a tests group to collect from all
 the test dirs (e.g. quick) or a name of a tests group to collect from
 a specific tests dir in the form of <test dir>/<group name> (e.g. xfs/quick).
+If you want to run all the tests in the test suite, use "-g all" to specify all
+groups.
 
 exclude_file argument refers to a name of a file inside each test directory.
 for every test dir where this file is found, the listed test names are
@@ -220,6 +222,12 @@ _prepare_test_list()
 	fi
 
 	# Specified groups to include
+	# Note that the CLI processing adds a leading space to the first group
+	# parameter, so we have to catch that here checking for "all"
+	if ! $have_test_arg && [ "$GROUP_LIST" == " all" ]; then
+		# no test numbers, do everything
+		get_all_tests
+	else
 		for group in $GROUP_LIST; do
 			list=$(get_group_list $group)
 			if [ -z "$list" ]; then
@@ -232,10 +240,6 @@ _prepare_test_list()
 							echo "$t" >>$tmp.list
 			done
 		done
-
-	if ! $have_test_arg && [ -z "$GROUP_LIST" ]; then
-		# no test numbers, do everything
-		get_all_tests
 	fi
 
 	# Specified groups to exclude
@@ -364,6 +368,10 @@ if $have_test_arg; then
 
 		shift
 	done
+elif [ -z "$GROUP_LIST" ]; then
+	# default group list is the auto group. If any other group or test is
+	# specified, we use that instead.
+	GROUP_LIST="auto"
 fi
 
 # we need common/rc