Plack::Util::load_psgi("MyApp::PSGIRunner") would now DWIM.

Also it uses require() instead of do().

lib/Plack/Util.pm

@@ -93,12 +93,19 @@ sub foreach {
     }
 }
 
+sub class_to_file {
+    my $class = shift;
+    $class =~ s!::!/!g;
+    $class . ".pm";
+}
+
 sub load_psgi {
-    my $file = shift;
+    my $stuff = shift;
 
-    my $app = do $file;
+    my $file = $stuff =~ /^[a-zA-Z0-9\_\:]+$/ ? class_to_file($stuff) : $stuff;
+    my $app = require $file;
     return $app->to_app if $app and Scalar::Util::blessed($app) and $app->can('to_app');
-    return $app if $app and ref $app eq 'CODE' or overload::Method($app, '&{}');
+    return $app if $app and (ref $app eq 'CODE' or overload::Method($app, '&{}'));
 
     if (my $e = $@ || $!) {
         die "Can't load $file: $e";

t/Plack-Util/Hello.pm

@@ -0,0 +1,11 @@
+package Hello;
+
+sub to_app {
+    return sub {
+        return [200, ['Content-Type', 'text/plain'], ['Hello']];
+    };
+}
+
+__PACKAGE__->to_app;
+
+

t/Plack-Util/hello.psgi

@@ -0,0 +1 @@
+sub { return [200, ['Content-Type', 'text/plain'], ['Hello']] };

t/Plack-Util/load.t

@@ -0,0 +1,28 @@
+use strict;
+use Plack::Util;
+use Plack::Test;
+use HTTP::Request::Common;
+use Test::More;
+
+{
+    my $app = Plack::Util::load_psgi("t/Plack-Util/hello.psgi");
+    ok $app;
+
+    test_psgi $app, sub {
+        is $_[0]->(GET "/")->content, "Hello";
+    };
+}
+
+{
+    use lib "t/Plack-Util";
+    my $app = Plack::Util::load_psgi("Hello");
+    ok $app;
+    test_psgi $app, sub {
+        is $_[0]->(GET "/")->content, "Hello";
+    };
+}
+
+
+
+
+done_testing;