Testsuite - Improve testsuite_user assuming it's NOT in Slurm DB

Improve testsuite_user docs.
Add a log_warn on check_run_as_user in case user is on DB.

Bug 9313

Signed-off-by: Chad Vizino <chad@schedmd.com>

testsuite/expect/README

@@ -42,8 +42,9 @@ testsuite_subtest_details:    add details of subtest in the summary [fail]
                               possible values: all, fail, fail_skip or none
 testsuite_testproc_details:   add details of testprocs in the summary [fail]
                               possible values: all, fail, fail_skip or none
-testsuite_user:               username that may be used when an admin user
-                              such as slurm or root is not desired
+testsuite_user:               a system username that is NOT on the Slurm DB
+                              that may be used to sudo commands as him
+                              instead of current user (see check_run_as_user)
 
 The testsuite needs at least one cluster-wide shared file system.
 By default, we assume that it's the testsuite/expect directory (i.e. ".").

testsuite/expect/globals

@@ -808,6 +808,10 @@ proc tolerance { expected observed tolerance_expression } {
 #	check. Calling user should be permitted to run_commands as the
 #	supplied user using sudo without password.
 #	See the -user option of run_command.
+#	This proc also log_warn a message if user already exists in the DB
+#	because most probably this user is testsuite_user and that user is
+#	expected NOT to be in the DB and could potentially be removed from it by
+#	the test.
 #
 # RETURN VALUE
 #	Returns a boolean value indicating whether the calling user may
@@ -824,6 +828,11 @@ proc check_run_as_user user {
 	if {[run_command_status -none -user $user "$bin_id -un"]} {
 		return false
 	}
+
+	if {[get_admin_level $user] != ""} {
+		log_warn "User $user already exists in DB, but it's probable that it's going to be removed by the test cleanup"
+	}
+
 	return true
 }
 
@@ -872,6 +881,7 @@ proc check_run_as_user user {
 #	-user <user>
 #		Attempt to execute command as <user>. Note that sudo must be
 #		properly configured to permit the caller to execute as <user>.
+#		See check_run_as_user.
 #
 # ARGUMENTS
 #	command