diff --git a/t/qpsmtpd.t b/t/qpsmtpd.t
index f02ce6c..ed854e3 100644
--- a/t/qpsmtpd.t
+++ b/t/qpsmtpd.t
@@ -6,8 +6,13 @@ use Data::Dumper;
 use Test::More;
 
 use lib 'lib';      # test lib/Qpsmtpd (vs site_perl)
-BEGIN { use_ok('Qpsmtpd'); }
-BEGIN { use_ok('Qpsmtpd::Constants'); }
+BEGIN {
+    use_ok('Qpsmtpd');
+    use_ok('Qpsmtpd::Constants');
+}
+
+use lib 't';
+use_ok('Test::Qpsmtpd');
 
 my $qp = bless {}, 'Qpsmtpd';
 
@@ -23,11 +28,6 @@ __load_logging();
 
 done_testing();
 
-sub __config {
-    my @r = $qp->config('badhelo');
-    ok( $r[0], "config, badhelo, @r");
-};
-
 sub __get_qmail_config {
     ok( !$qp->get_qmail_config('me'), "get_qmail_config, me");
 
@@ -83,3 +83,103 @@ sub __authenticated {
     $qp->{_auth} = 0;
     ok( !$qp->authenticated(), "authenticated, false");
 };
+
+sub __config {
+    my @r = $qp->config('badhelo');
+    ok( $r[0], "config, badhelo, @r");
+    my $a = FakeAddress->new( test => 'test value' );
+    ok( my ($qp,$cxn) = Test::Qpsmtpd->new_conn(), "get new connection" );
+    my @test_data = (
+        {
+            pref     => 'size_threshold',
+            hooks    => {
+                user_config => [],
+                config      => [],
+            },
+            expected => {
+                user   => 10000,
+                global => 10000,
+            },
+            descr    => 'no user or global config hooks, fall back to config file',
+        },
+        {
+            pref     => 'timeout',
+            hooks    => {
+                user_config => [],
+                config      => [],
+            },
+            expected => {
+                user   => 1200,
+                global => 1200,
+            },
+            descr    => 'no user or global config hooks, fall back to defaults',
+        },
+        {
+            pref     => 'timeout',
+            hooks    => {
+                user_config => [DECLINED],
+                config      => [DECLINED],
+            },
+            expected => {
+                user   => 1200,
+                global => 1200,
+            },
+            descr    => 'user and global config hooks decline, fall back to defaults',
+        },
+        {
+            pref     => 'timeout',
+            hooks    => {
+                user_config => [DECLINED],
+                config      => [OK,1000],
+            },
+            expected => {
+                user   => 1000,
+                global => 1000,
+            },
+            descr    => 'user hook declines, global hook returns',
+        },
+        {
+            pref     => 'timeout',
+            hooks    => {
+                user_config => [OK,500],
+                config      => [OK,undef],
+            },
+            expected => {
+                user   => 500,
+                global => undef,
+            },
+            descr    => 'user hook returns int, global hook returns undef',
+        },
+        {
+            pref     => 'timeout',
+            hooks    => {
+                user_config => [OK,undef],
+                config      => [OK,1000],
+            },
+            expected => {
+                user   => undef,
+                global => 1000,
+            },
+            descr    => 'user hook returns undef, global hook returns int',
+        },
+    );
+    for my $t (@test_data) {
+        for my $hook (qw( config user_config )) {
+             $qp->hooks->{$hook}
+                = @{ $t->{hooks}{$hook} }
+                    ? [{ name => 'test hook', code => sub { return @{ $t->{hooks}{$hook} }} }]
+                    : undef;
+        }
+        is( $qp->config($t->{pref},$a), $t->{expected}{user},   "User config: $t->{descr}");
+        is( $qp->config($t->{pref}),    $t->{expected}{global}, "Global config: $t->{descr}");
+    }
+}
+
+package FakeAddress;
+
+sub new {
+   shift;
+   return bless {@_};
+}
+
+sub address { } # pass the can('address') conditional