diff --git a/lib/MasterSlave.pm b/lib/MasterSlave.pm
index 47dab9ae..9c1083be 100644
--- a/lib/MasterSlave.pm
+++ b/lib/MasterSlave.pm
@@ -32,8 +32,18 @@ use constant PTDEBUG => $ENV{PTDEBUG} || 0;
 sub check_recursion_method {
    my ($methods) = @_;
 
-   if ( @$methods != 1 ) {
-      if ( grep({ !m/processlist|hosts/i } @$methods)
+   # Check that each method is valid.
+   foreach my $method ( @$methods ) {
+      die "Invalid recursion method: " . ($method || 'undef') . "\n"
+         unless $method && $method =~ m/^(?:processlist$|hosts$|none$|cluster|dsn=)/i;
+   }
+
+   # Check for invalid combination of methods.
+   if ( @$methods > 1 ) {
+      if ( grep( { m/none/ } @$methods) && grep( {! m/none/ } @$methods) ) {
+            die "--recursion-method=none cannot be combined with other methods\n";
+      }
+      elsif ( grep({ !m/processlist|hosts/i } @$methods)
             && $methods->[0] !~ /^dsn=/i )
       {
          die  "Invalid combination of recursion methods: "
@@ -41,11 +51,8 @@ sub check_recursion_method {
             . "Only hosts and processlist may be combined.\n"
       }
    }
-   else {
-      my ($method) = @$methods;
-      die "Invalid recursion method: " . ( $method || 'undef' )
-         unless $method && $method =~ m/^(?:processlist$|hosts$|none$|dsn=)/i;
-   }
+
+   return;
 }
 
 sub new {
diff --git a/t/lib/MasterSlave.t b/t/lib/MasterSlave.t
index ad14fa6a..68c2647b 100644
--- a/t/lib/MasterSlave.t
+++ b/t/lib/MasterSlave.t
@@ -11,10 +11,6 @@ use warnings FATAL => 'all';
 use English qw(-no_match_vars);
 use Test::More;
 
-if ( !$ENV{SLOW_TESTS} ) {
-   plan skip_all => "lib/MasterSlave.t is a top 5 slowest file; set SLOW_TESTS=1 to enable it.";
-}
-
 use MasterSlave;
 use DSNParser;
 use VersionParser;
@@ -709,28 +705,51 @@ is(
 # ############################################################################
 # Invalid recursion methods are caught
 # ############################################################################
-local $EVAL_ERROR;
 eval {
    MasterSlave::check_recursion_method([qw(stuff)])
 };
-
 like(
    $EVAL_ERROR,
    qr/Invalid recursion method: stuff/,
    "--recursion-method stuff causes error"
 );
 
-local $EVAL_ERROR;
 eval {
    MasterSlave::check_recursion_method([qw(processlist stuff)])
 };
-
 like(
    $EVAL_ERROR,
-   qr/Invalid combination of recursion methods: processlist, stuff/,
+   qr/Invalid recursion method: stuff/,
    "--recursion-method processlist,stuff causes error",
 );
 
+eval {
+   MasterSlave::check_recursion_method([qw(none hosts)])
+};
+like(
+   $EVAL_ERROR,
+   qr/none cannot be combined with other methods/,
+   "--recursion-method none,hosts"
+);
+
+eval {
+   MasterSlave::check_recursion_method([qw(cluster none)])
+};
+like(
+   $EVAL_ERROR,
+   qr/none cannot be combined with other methods/,
+   "--recursion-method cluster,none"
+);
+
+eval {
+   MasterSlave::check_recursion_method([qw(none none)])
+};
+like(
+   $EVAL_ERROR,
+   qr/Invalid combination of recursion methods: none, none/,
+   "--recursion-method none,none"
+);
+
 # #############################################################################
 # Done.
 # #############################################################################