diff --git a/spec/lib/msf/core/option_group_spec.rb b/spec/lib/msf/core/option_group_spec.rb
index cc00cc3186..152370887e 100644
--- a/spec/lib/msf/core/option_group_spec.rb
+++ b/spec/lib/msf/core/option_group_spec.rb
@@ -47,4 +47,92 @@ RSpec.describe Msf::OptionGroup do
       end
     end
   end
+
+  describe '#validate' do
+    let(:required_option_name) { 'required_name' }
+    let(:option_names) { ['not_required_name', required_option_name] }
+    let(:required_names) { [required_option_name] }
+    let(:options) { instance_double(Msf::OptionContainer) }
+    let(:datastore) { instance_double(Msf::DataStoreWithFallbacks) }
+
+    context 'when there are no required options' do
+      subject { described_class.new(name: 'name', description: 'description', option_names: option_names) }
+
+      context 'when no values are set for the options' do
+
+        before(:each) do
+          allow(options).to receive(:[]).and_return(instance_double(Msf::OptBase))
+          allow(datastore).to receive(:[]).and_return(nil)
+        end
+
+        it 'validates the options in the group' do
+          expect { subject.validate(options, datastore) }.not_to raise_error(Msf::OptionValidateError)
+        end
+      end
+
+      context 'when values are set for the options' do
+
+        before(:each) do
+          allow(options).to receive(:[]).and_return(instance_double(Msf::OptBase))
+          allow(datastore).to receive(:[]).and_return('OptionValue')
+        end
+
+        it 'validates the options in the group' do
+          expect { subject.validate(options, datastore) }.not_to raise_error(Msf::OptionValidateError)
+        end
+      end
+
+      context 'when the options have not been registered' do
+
+        before(:each) do
+          allow(options).to receive(:[]).and_return(nil)
+        end
+
+        it 'does not attempt to validate the options' do
+          expect { subject.validate(options, datastore) }.not_to raise_error(Msf::OptionValidateError)
+        end
+      end
+    end
+
+    context 'when there is a required option' do
+      subject { described_class.new(name: 'name', description: 'description', option_names: option_names, required_options: required_names) }
+      let(:error_message) { "The following options failed to validate: #{required_option_name}." }
+
+      context 'when no values are set for the options' do
+
+        before(:each) do
+          allow(options).to receive(:[]).and_return(instance_double(Msf::OptBase))
+          allow(datastore).to receive(:[]).and_return(nil)
+        end
+
+        it 'raises an error only for the required option' do
+          expect { subject.validate(options, datastore) }.to raise_error(Msf::OptionValidateError).with_message(error_message)
+        end
+      end
+
+      context 'when values are set for the options' do
+
+        before(:each) do
+          allow(options).to receive(:[]).and_return(instance_double(Msf::OptBase))
+          allow(datastore).to receive(:[]).and_return('OptionValue')
+        end
+
+        it 'validates the options in the group' do
+          expect { subject.validate(options, datastore) }.not_to raise_error(Msf::OptionValidateError)
+        end
+      end
+
+      context 'when the options have not been registered' do
+
+        before(:each) do
+          allow(options).to receive(:[]).and_return(nil)
+        end
+
+        it 'does not attempt to validate the options' do
+          expect { subject.validate(options, datastore) }.not_to raise_error(Msf::OptionValidateError)
+        end
+      end
+    end
+
+  end
 end
diff --git a/spec/lib/msf/core/optional_session/mssql_spec.rb b/spec/lib/msf/core/optional_session/mssql_spec.rb
new file mode 100644
index 0000000000..6b098c09d7
--- /dev/null
+++ b/spec/lib/msf/core/optional_session/mssql_spec.rb
@@ -0,0 +1,14 @@
+# -*- coding:binary -*-
+# frozen_string_literal: true
+
+require 'spec_helper'
+
+RSpec.describe Msf::OptionalSession::MSSQL do
+  subject(:mod) do
+    mod = ::Msf::Module.new
+    mod.extend described_class
+    mod
+  end
+
+  it_behaves_like Msf::OptionalSession
+end
diff --git a/spec/lib/msf/core/optional_session/mysql_spec.rb b/spec/lib/msf/core/optional_session/mysql_spec.rb
new file mode 100644
index 0000000000..87bc908cca
--- /dev/null
+++ b/spec/lib/msf/core/optional_session/mysql_spec.rb
@@ -0,0 +1,14 @@
+# -*- coding:binary -*-
+# frozen_string_literal: true
+
+require 'spec_helper'
+
+RSpec.describe Msf::OptionalSession::MySQL do
+  subject(:mod) do
+    mod = ::Msf::Module.new
+    mod.extend described_class
+    mod
+  end
+
+  it_behaves_like Msf::OptionalSession
+end
diff --git a/spec/lib/msf/core/optional_session/postgresql_spec.rb b/spec/lib/msf/core/optional_session/postgresql_spec.rb
new file mode 100644
index 0000000000..b48b11add5
--- /dev/null
+++ b/spec/lib/msf/core/optional_session/postgresql_spec.rb
@@ -0,0 +1,14 @@
+# -*- coding:binary -*-
+# frozen_string_literal: true
+
+require 'spec_helper'
+
+RSpec.describe Msf::OptionalSession::PostgreSQL do
+  subject(:mod) do
+    mod = ::Msf::Module.new
+    mod.extend described_class
+    mod
+  end
+
+  it_behaves_like Msf::OptionalSession
+end
diff --git a/spec/lib/msf/core/optional_session/smb_spec.rb b/spec/lib/msf/core/optional_session/smb_spec.rb
new file mode 100644
index 0000000000..7726bb863c
--- /dev/null
+++ b/spec/lib/msf/core/optional_session/smb_spec.rb
@@ -0,0 +1,14 @@
+# -*- coding:binary -*-
+# frozen_string_literal: true
+
+require 'spec_helper'
+
+RSpec.describe Msf::OptionalSession::SMB do
+  subject(:mod) do
+    mod = ::Msf::Module.new
+    mod.extend described_class
+    mod
+  end
+
+  it_behaves_like Msf::OptionalSession
+end
diff --git a/spec/support/shared/examples/msf/core/optional_session.rb b/spec/support/shared/examples/msf/core/optional_session.rb
new file mode 100644
index 0000000000..c1a1080f21
--- /dev/null
+++ b/spec/support/shared/examples/msf/core/optional_session.rb
@@ -0,0 +1,110 @@
+# -*- coding:binary -*-
+# frozen_string_literal: true
+
+require 'spec_helper'
+
+RSpec.shared_examples_for Msf::OptionalSession do
+  include_context 'Msf::Simple::Framework'
+
+  let(:options) { instance_double(Msf::OptionContainer) }
+  let(:datastore) { instance_double(Msf::DataStoreWithFallbacks) }
+  let(:session) { instance_double(Msf::Sessions::SMB) }
+  let(:session_group) { instance_double(Msf::OptionGroup) }
+  let(:rhost_group) { instance_double(Msf::OptionGroup) }
+  let(:groups) do
+    {
+      'SESSION' => session_group,
+      'RHOST' => rhost_group
+    }
+  end
+  describe '#validate' do
+    before(:each) do
+      allow(options).to receive(:validate)
+      allow(options).to receive(:[]).and_return(instance_double(Msf::OptBase))
+      allow(options).to receive(:groups).and_return(groups)
+      allow(mod).to receive(:options).and_return(options)
+      allow(mod).to receive(:datastore).and_return(datastore)
+      allow(mod).to receive(:framework).and_return(framework)
+      allow(session_group).to receive(:validate)
+      allow(rhost_group).to receive(:validate)
+    end
+
+    context 'when neither SESSION or RHOST are set' do
+      before(:each) do
+        allow(mod).to receive(:rhost).and_return(nil)
+        allow(mod).to receive(:session).and_return(nil)
+      end
+
+      it 'raises an error' do
+        expect { mod.validate }.to raise_error(Msf::OptionValidateError).with_message('A SESSION or RHOST must be provided')
+      end
+    end
+
+    context 'when both SESSION and RHOST are set' do
+      before(:each) do
+        allow(datastore).to receive(:[]).with('SESSION').and_return('SESSION_ID')
+        allow(datastore).to receive(:[]).with('RHOST').and_return('RHOST_VALUE')
+        allow(mod).to receive(:session).and_return(session)
+        allow(mod).to receive(:rhost).and_return('RHOST_VALUE')
+      end
+
+      it 'validates the SESSION only' do
+        mod.validate
+        expect(session_group).to have_received(:validate).once
+        expect(rhost_group).not_to have_received(:validate)
+      end
+    end
+
+    context 'when only RHOST is set' do
+      before(:each) do
+        allow(datastore).to receive(:[]).with('RHOST').and_return('RHOST_VALUE')
+        allow(datastore).to receive(:[]).with('SESSION').and_return(nil)
+        allow(mod).to receive(:rhost).and_return('RHOST_VALUE')
+        allow(mod).to receive(:session).and_return(nil)
+      end
+
+      it 'only validates the RHOST group' do
+        mod.validate
+        expect(rhost_group).to have_received(:validate).once
+        expect(session_group).not_to have_received(:validate)
+      end
+    end
+
+    context 'when only SESSION is set' do
+      before(:each) do
+        allow(datastore).to receive(:[]).with('SESSION').and_return('SESSION_ID')
+        allow(datastore).to receive(:[]).with('RHOST').and_return(nil)
+        allow(mod).to receive(:session).and_return(session)
+        allow(mod).to receive(:rhost).and_return(nil)
+      end
+
+      it 'validates the SESSION only' do
+        mod.validate
+        expect(session_group).to have_received(:validate).once
+        expect(rhost_group).not_to have_received(:validate)
+      end
+
+      context 'when the session is not the correct type' do
+        before(:each) do
+          allow(mod).to receive(:session_types).and_return(['correct_session_type'])
+          allow(session).to receive(:type).and_return('wrong_session_type')
+        end
+
+        it 'should raise an error about the wrong session type' do
+          expect { mod.validate }.to raise_error(Msf::OptionValidateError) { |error| expect(error.options).to eq ['SESSION'] }
+        end
+      end
+
+      context 'when the session is the correct type' do
+        before(:each) do
+          allow(mod).to receive(:session_types).and_return(['correct_session_type'])
+          allow(session).to receive(:type).and_return('correct_session_type')
+        end
+
+        it 'should raise an error about the wrong session type' do
+          expect { mod.validate }.not_to raise_error
+        end
+      end
+    end
+  end
+end