add unit test

lib/msf/core/opt_address_local.rb

@@ -12,7 +12,7 @@ class OptAddressLocal < OptAddress
   def interfaces
     begin
       NetworkInterface.interfaces || []
-    rescue
+    rescue NetworkInterface::Error => e
       elog(e)
       []
     end

spec/lib/msf/core/opt_address_local_spec.rb

@@ -94,4 +94,17 @@
       end
     end
   end
+  describe '#interfaces' do
+    context 'getting errors' do
+      before(:each) do
+        allow(NetworkInterface).to receive(:interfaces).and_raise(NetworkInterface::Error)
+      end
+
+      it 'rescues and returns an empty array' do
+        expect(required_opt).to receive(:elog).with(an_instance_of(NetworkInterface::Error))
+        result = required_opt.interfaces()
+        expect(result).to eq([])
+      end
+    end
+  end
 end