diff --git a/lib/msf/util/java_deserialization.rb b/lib/msf/util/java_deserialization.rb
index df3316dfd2..4c214f7ff5 100644
--- a/lib/msf/util/java_deserialization.rb
+++ b/lib/msf/util/java_deserialization.rb
@@ -4,12 +4,12 @@ module Util
 require 'json'
 require 'base64'
 
-PAYLOAD_FILENAME="ysoserial_payloads.json"
-
 #TODO: Support ysoserial alongside ysoserial-modified payloads (including cmd, bash, powershell, none)
 
 class JavaDeserialization
 
+  PAYLOAD_FILENAME = "ysoserial_payloads.json"
+
   def self.ysoserial_payload(payloadName, command=nil)
     # Open the JSON file and parse it
     begin
diff --git a/spec/lib/msf/util/java_deserialization_spec.rb b/spec/lib/msf/util/java_deserialization_spec.rb
new file mode 100644
index 0000000000..409947d87e
--- /dev/null
+++ b/spec/lib/msf/util/java_deserialization_spec.rb
@@ -0,0 +1,80 @@
+require 'rex'
+require 'msf/util/java_deserialization'
+
+RSpec.describe Msf::Util::JavaDeserialization do
+  let(:payload_name) do
+    'PAYLOAD_NAME'
+  end
+
+  let(:default_command) do
+    nil
+  end
+
+  describe '#ysoserial_payload' do
+    context 'when default payload name is changed' do
+      it 'raises a RuntimeError' do
+        payload_filename_constant = Msf::Util::JavaDeserialization.const_get(:PAYLOAD_FILENAME)
+        Msf::Util::JavaDeserialization.const_set(:PAYLOAD_FILENAME, 'INVALID')
+        expect{Msf::Util::JavaDeserialization::ysoserial_payload(payload_name, default_command)}.to raise_error(RuntimeError)
+        Msf::Util::JavaDeserialization.const_set(:PAYLOAD_FILENAME, payload_filename_constant)
+      end
+    end
+
+    context 'when default payload is not found' do
+      it 'raises a RuntimeError' do
+        allow(File).to receive(:join).and_return('INVALID')
+        expect{Msf::Util::JavaDeserialization::ysoserial_payload(payload_name, default_command)}.to raise_error(RuntimeError)
+      end
+    end
+
+    context 'when default payload is not JSON format' do
+      it 'raises a JSON::ParserError error' do
+        allow(File).to receive(:read).and_return('BAD DATA')
+        expect{Msf::Util::JavaDeserialization::ysoserial_payload(payload_name, default_command)}.to raise_error(JSON::ParserError)
+      end
+    end
+
+    context 'when payload status is unsupported' do
+      it 'raises a unsupported error' do
+        json_data = %Q|{"BeanShell1":{"status":"unsupported","bytes":"AAAA"}}|
+        allow(File).to receive(:read).and_return(json_data)
+        expect{Msf::Util::JavaDeserialization::ysoserial_payload(payload_name, default_command)}.to raise_error(ArgumentError)
+      end
+    end
+
+    context 'when payload status is static' do
+      let(:payload_name) do
+        'BeanShell1'
+      end
+
+      it 'returns a Base64 string' do
+        original_bytes = 'AAAA'
+        b64 = Rex::Text.encode_base64(original_bytes)
+        json_data = %Q|{"BeanShell1":{"status":"static","bytes":"#{b64}"}}|
+        allow(File).to receive(:read).and_return(json_data)
+        p = Msf::Util::JavaDeserialization::ysoserial_payload(payload_name, default_command)
+        expect(p).to eq(original_bytes)
+      end
+    end
+
+    context 'when payload status is dynamic' do
+      let(:payload_name) do
+        'BeanShell1'
+      end
+
+      context 'when missing a command' do
+        it 'raises an argument error' do
+          expect{Msf::Util::JavaDeserialization::ysoserial_payload(payload_name, default_command)}.to raise_error(ArgumentError)
+        end
+      end
+
+      context 'when a command is provided' do
+        it 'returns serialized data' do
+          default_command = 'id'
+          p = Msf::Util::JavaDeserialization::ysoserial_payload(payload_name, default_command)
+          expect(p).to include('java.awt.event')
+        end
+      end
+    end
+  end
+end