TTO-153 Logged-in user doesn't see collections despite matching username

- `Utils::Get_Remote_User_Names` modified to include case-preserved `REMOTE_USER` and `eppn` components.

Utils.pm

@@ -103,10 +103,18 @@ sub Get_Legacy_Remote_User {
     return $remote_user;
 }
 
+# Returns an array of unique (Get_Remote_User, case-preserving REMOTE_USER if it exists,
+# EPPN components in case-preserving and lowercase-only forms)
 sub Get_Remote_User_Names {
     my @usernames = ( Get_Remote_User() );
+    if ( exists $ENV{REMOTE_USER} && defined $ENV{REMOTE_USER} && $ENV{REMOTE_USER} ) {
+        $value = $ENV{REMOTE_USER};
+        push @usernames, $value unless grep(/^$value$/, @usernames);
+    }
     if ( defined $ENV{eppn} && $ENV{eppn} ) {
-        foreach my $value ( split(/;/, lc $ENV{eppn} ) ) {
+        foreach my $value ( split(/;/, $ENV{eppn} ) ) {
+            push @usernames, $value unless ( grep(/^$value$/, @usernames) );
+            $value = lc $value;
             push @usernames, $value unless ( grep(/^$value$/, @usernames) );
         }
     }

t/Utils.t

@@ -0,0 +1,32 @@
+#!/usr/bin/perl
+
+use strict;
+use warnings;
+use Test::More;
+
+use Utils;
+
+local %ENV = %ENV;
+
+subtest "Get_Remote_User_Names" => sub {
+  my $save_remote_user = $ENV{REMOTE_USER};
+  my $save_eppn = $ENV{eppn};
+  $ENV{eppn} = 'EPPN@default.invalid';
+  $ENV{REMOTE_USER} = 'REMOTE_USER@default.invalid';
+  subtest "contains lowercase REMOTE_USER" => sub {
+    ok(1 <= scalar grep(/remote_user/, Utils::Get_Remote_User_Names()));
+  };
+  subtest "contains case-preserved REMOTE_USER" => sub {
+    ok(1 <= scalar grep(/REMOTE_USER/, Utils::Get_Remote_User_Names()));
+  };
+  subtest "contains lowercase EPPN" => sub {
+    ok(1 <= scalar grep(/eppn/, Utils::Get_Remote_User_Names()));
+  };
+  subtest "contains case-preserved EPPN" => sub {
+    ok(1 <= scalar grep(/EPPN/, Utils::Get_Remote_User_Names()));
+  };
+  $ENV{REMOTE_USER} = $save_remote_user;
+  $ENV{eppn} = $save_eppn;
+};
+
+done_testing();