Use consistent return values and provide default initalizations

Add inital versions of Layer 2 test classes

lib/SNMP/Info/Layer2/C1900.pm

@@ -200,6 +200,8 @@ sub set_i_duplex_admin {
 
     my $iid = $c1900->c1900_p_ifindex($port);
 
+    return 0 unless $iid->{$port};
+
     $duplex = lc($duplex);
 
     return 0 unless defined $duplexes{$duplex};
@@ -212,17 +214,17 @@ sub i_vlan {
     my $partial = shift;
 
     # Overlap allows more than one VLAN per port.  Unable to determine default
-    my $overlap 
+    my $overlap
         = $c1900->bridgeGroupAllowMembershipOverlap()
         || $c1900->vlanAllowMembershipOverlap()
         || 'disabled';
 
     if ( $overlap eq 'enabled' ) {
-        return;
+        return {};
     }
 
     my $member_of = $c1900->bridgeGroupMemberPortOfBridgeGroup()
-        || $c1900->vlanMemberPortOfVlan();
+        || $c1900->vlanMemberPortOfVlan() || {};
 
     my $i_pvid = {};
     foreach my $idx ( keys %$member_of ) {
@@ -244,7 +246,7 @@ sub i_vlan_membership {
     my $partial = shift;
 
     my $member_of = $c1900->bridgeGroupMemberPortOfBridgeGroup()
-        || $c1900->vlanMemberPortOfVlan();
+        || $c1900->vlanMemberPortOfVlan() || {};
 
     my $i_vlan_membership = {};
     foreach my $idx ( keys %$member_of ) {
@@ -261,7 +263,7 @@ sub i_vlan_membership {
     return $i_vlan_membership;
 }
 
-sub i_vlan_membership_untagged { return; }
+sub i_vlan_membership_untagged { return {}; }
 
 sub bp_index {
     my $c1900   = shift;

lib/SNMP/Info/Layer2/C2900.pm

@@ -190,7 +190,7 @@ sub set_i_duplex_admin {
     return $c2900->set_c2900_p_duplex_admin( $duplexes{$duplex}, $iid );
 }
 
-# Use i_descritption for port key, cuz i_name can be manually entered.
+# Use i_description for port key, cuz i_name can be manually entered.
 sub interfaces {
     my $c2900   = shift;
     my $partial = shift;

lib/SNMP/Info/Layer2/Catalyst.pm

@@ -70,7 +70,7 @@ $VERSION = '3.54';
 sub i_physical {
     my $cat = shift;
 
-    my $p_port = $cat->p_port();
+    my $p_port = $cat->p_port() || {};
 
     my %i_physical;
     foreach my $port ( keys %$p_port ) {
@@ -104,8 +104,8 @@ sub os_ver {
 # Workaround for incomplete bp_index
 sub bp_index {
     my $cat     = shift;
-    my $p_index = $cat->p_port();
-    my $b_index = $cat->p_oidx();
+    my $p_index = $cat->p_port() || {};
+    my $b_index = $cat->p_oidx() || {};
 
     my %bp_index;
     foreach my $iid ( keys %$p_index ) {

lib/SNMP/Info/Layer2/Kentrox.pm

@@ -66,6 +66,7 @@ sub os_ver {
     if ( $descr =~ /^\S+\s\S+\s\S+\s(\S+)/){
         return $1;
     }
+    return;
 }
 
 sub serial {
@@ -75,7 +76,7 @@ sub serial {
         my $str = substr($1,8,10);
         return $str;
     }
-
+    return;
 }
 sub vendor {
     return 'Kentrox';
@@ -87,6 +88,7 @@ sub model {
     if ( $descr =~ /^(\S+\s\S+)/){
         return $1;
     }
+    return;
 }
 
 1;