diff --git a/spec/lib/msf/core/module_set_spec.rb b/spec/lib/msf/core/module_set_spec.rb
new file mode 100644
index 0000000000..ec9d078924
--- /dev/null
+++ b/spec/lib/msf/core/module_set_spec.rb
@@ -0,0 +1,59 @@
+require 'spec_helper'
+
+RSpec.describe Msf::ModuleSet do
+  subject(:module_set) {
+    described_class.new(module_type)
+  }
+
+  let(:module_type) {
+    FactoryGirl.generate :mdm_module_detail_mtype
+  }
+
+  context '#rank_modules' do
+    subject(:rank_modules) {
+      module_set.send(:rank_modules)
+    }
+
+    context 'with Msf::SymbolicModule' do
+      before(:each) do
+        module_set['a'] = Msf::SymbolicModule
+        module_set['b'] = Msf::SymbolicModule
+        module_set['c'] = Msf::SymbolicModule
+      end
+
+      context 'create' do
+        context 'returns nil' do
+          before(:each) do
+            allow(module_set).to receive(:create).and_return(nil)
+          end
+
+          specify {
+            expect {
+              rank_modules
+            }.not_to raise_error
+          }
+        end
+
+        context 'does not return nil' do
+          context 'with Rank' do
+            it 'is ranked using Rank'
+          end
+
+          context 'without Rank' do
+            it 'is ranked as Normal'
+          end
+        end
+      end
+    end
+
+    context 'without Msf::SymbolicModule' do
+      context 'with Rank' do
+        it 'is ranked using Rank'
+      end
+
+      context 'without Rank' do
+        it 'is ranked as Normal'
+      end
+    end
+  end
+end
\ No newline at end of file