Add TAP tests for client programs

Reviewed-by: Pavel Stěhule <pavel.stehule@gmail.com>
Reviewed-by: Erik Rijkers <er@xs4all.nl>

src/bin/scripts/t/070_dropuser.pl

@@ -0,0 +1,16 @@
+use strict;
+use warnings;
+use TestLib;
+use Test::More tests => 5;
+
+program_help_ok('dropuser');
+program_version_ok('dropuser');
+program_options_handling_ok('dropuser');
+
+my $tempdir = tempdir;
+start_test_server $tempdir;
+
+psql 'postgres', 'CREATE ROLE foobar1';
+issues_sql_like(['dropuser', 'foobar1'], qr/statement: DROP ROLE foobar1/, 'SQL DROP ROLE run');
+
+command_fails(['dropuser', 'nonexistent'], 'fails with nonexistent user');