diff -ur libtest-unit-perl-0.24.debian/lib/Test/Unit/Assert.pm libtest-unit-perl-0.24/lib/Test/Unit/Assert.pm
--- libtest-unit-perl-0.24.debian/lib/Test/Unit/Assert.pm	2004-05-18 14:35:41.000000000 -0400
+++ libtest-unit-perl-0.24/lib/Test/Unit/Assert.pm	2004-05-18 15:09:53.000000000 -0400
@@ -219,6 +219,7 @@
 }
 
 # Shamelessly pinched from Test::More and adapted to Test::Unit.
+our %Seen_Refs = ();
 our @Data_Stack;
 my $DNE = bless [], 'Does::Not::Exist';
 sub assert_deep_equals {
@@ -236,23 +237,36 @@
     }
 
     local @Data_Stack = ();
+    local %Seen_Refs = ();
     if (! $self->_deep_check($this, $that)) {
         Test::Unit::Failure->throw(
             -text => @_ ? join('', @_)
                         : $self->_format_stack(@Data_Stack)
         );
     }
-}    
+}
 
 sub _deep_check {
     my $self = shift;
     my ($e1, $e2) = @_;
 
-    # Quiet uninitialized value warnings when comparing undefs.
-    local $^W = 0; 
+    if ( ! defined $e1 || ! defined $e2 ) {
+        return 1 if !defined $e1 && !defined $e2;
+        push @Data_Stack, { vals => [$e1, $e2] };
+        return 0;
+    }
+
+    return 0 if ( (defined $e1 && $e1 eq $DNE)
+                  || (defined $e2 && $e2 eq $DNE ));
 
     return 1 if $e1 eq $e2;
 
+    if ( ref $e1 && ref $e2 ) {
+        my $e2_ref = "$e2";
+        return 1 if defined $Seen_Refs{$e1} && $Seen_Refs{$e1} eq $e2_ref;
+        $Seen_Refs{$e1} = $e2_ref;
+    }
+
     if (UNIVERSAL::isa($e1, 'ARRAY') and UNIVERSAL::isa($e2, 'ARRAY')) {
         return $self->_eq_array($e1, $e2);
     }
Only in libtest-unit-perl-0.24/lib/Test/Unit: Assert.pm~
diff -ur libtest-unit-perl-0.24.debian/t/tlib/AssertTest.pm libtest-unit-perl-0.24/t/tlib/AssertTest.pm
--- libtest-unit-perl-0.24.debian/t/tlib/AssertTest.pm	2004-05-18 14:35:41.000000000 -0400
+++ libtest-unit-perl-0.24/t/tlib/AssertTest.pm	2004-05-18 15:07:56.000000000 -0400
@@ -11,6 +11,8 @@
 use Error qw/:try/;
 use Class::Inner;
 
+use Data::Dumper;
+
 use vars qw/@ISA/;
 @ISA = qw(Test::Unit::TestCase ExceptionChecker);
 
@@ -328,6 +330,19 @@
     $self->assert_not_null(10);
 }
 
+sub deep_clone {
+    my $x = $_[0];
+
+    no strict;
+
+    $Data::Dumper::Purity = 1;
+
+    eval Dumper( $x );
+
+    # Data::Dumper assigns to VAR1.
+    return $VAR1;
+}
+
 sub test_assert_deep_equals {
     my $self = shift;
 
@@ -366,6 +381,30 @@
         },
     );
 
+    my %family = ( john => { name => 'John Doe',
+                              spouse => undef,
+                              children => [],
+                           },
+                   jane => { name   => 'Jane Doe',
+                             spouse => undef,
+                             children => [],
+                           },
+                   baby => { name => 'Baby Doll',
+                             spouse => undef,
+                             children => [],
+                           },
+                 );
+    $family{john}{spouse} = $family{jane};
+    $family{jane}{spouse} = $family{john};
+    push @{$family{john}{children}}, $family{baby};
+    push @{$family{jane}{children}}, $family{baby};
+
+    my $copy = deep_clone( \%family );
+    $self->assert_deep_equals( \%family, $copy );
+
+    my $bad_copy = deep_clone( \%family );
+    $bad_copy->{jane}{spouse} = $bad_copy->{baby};
+
     my $differ = sub {
         my ($a, $b) = @_;
         qr/^Structures\ begin\ differing\ at: $ \n
@@ -381,6 +420,12 @@
         'Both arguments were not references' => [ '', 0    ],
          $differ->(qw/ARRAY HASH/)     => [ [],      {}      ],
          $differ->(qw/ARRAY HASH/)     => [ [1,2],   {1,2}   ],
+         $differ->( 'ARRAY', 'undef' ) => [ { 'test' => []}, 
+                                            { 'test' => undef } ],
+         $differ->( 'ARRAY', 'not\ exist' ) => [ { 'test' => []}, {} ],
+         $differ->( 'undef', 'ARRAY' ) => [ { 'test' => undef },
+                                            { 'test' => []} ],
+         $differ->( '', 'undef' ) => [ [ '' ], [ undef ] ],
          $differ->('not\ exist', "'3'") => [ [1,2],   [1,2,3] ],
          $differ->("'3'", 'not\ exist') => [ [1,2,3], [1,2]   ],
          $differ->("'wahhhhh'", "'wahhhh'") => [
@@ -398,6 +443,7 @@
                  },
              }
          ],
+         $differ->( 'HASH', 'undef') => [ \%family, $bad_copy ],
     );
 
     my @tests = ();
Only in libtest-unit-perl-0.24/t/tlib: AssertTest.pm~