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/080_pg_isready.pl

@@ -0,0 +1,15 @@
+use strict;
+use warnings;
+use TestLib;
+use Test::More tests => 5;
+
+program_help_ok('pg_isready');
+program_version_ok('pg_isready');
+program_options_handling_ok('pg_isready');
+
+command_fails(['pg_isready'], 'fails with no server running');
+
+my $tempdir = tempdir;
+start_test_server $tempdir;
+
+command_ok(['pg_isready'], 'succeeds with server running');