diff --git a/Gemfile b/Gemfile
index 6ebb7fc..d7d0f34 100644
--- a/Gemfile
+++ b/Gemfile
@@ -32,6 +32,9 @@ gem 'jquery-rails'
 # Use ActiveModel has_secure_password
 # gem 'bcrypt', '~> 3.1.7'
 
+# a library for generating fake data.
+gem 'faker'
+
 # Use Capistrano for deployment
 # gem 'capistrano-rails', group: :development
 
@@ -44,18 +47,20 @@ group :development, :test do
 
   # rspec
   gem 'rspec-rails', '~> 3.5'
-  gem 'shoulda-matchers'
 
   # RSpec::JsonExpectations
   gem 'rspec-json_expectations'
 end
 
 group :test do
-  # for build strategies
-  gem 'factory_girl_rails'
-
-  # database cleaner
-  gem 'database_rewinder'
+  # a library for setting up Ruby objects as test data.
+  gem 'factory_girl_rails', '~> 4.0'
+  # shoulda-matcher provides Rspec and Minitest compatible one liners that test common Rails functionality.
+  gem 'shoulda-matchers', '~> 3.1'
+  # strategies for cleaning database in Ruby.
+  gem 'database_cleaner'
+  # an IRB alternative and runtime developer console.
+  gem 'pry'
 end
 
 group :development do
@@ -70,7 +75,7 @@ end
 # Windows does not include zoneinfo files, so bundle the tzinfo-data gem
 gem 'tzinfo-data', platforms: [:mingw, :mswin, :x64_mingw, :jruby]
 
-# json genarator
-gem 'active_model_serializers'
+# ActiveModel::Serializer implementation and Rails hooks.
+gem 'active_model_serializers', '~> 0.10.0'
 
 gem 'foreman'
diff --git a/Gemfile.lock b/Gemfile.lock
index f87d02e..1d81c95 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -48,8 +48,9 @@ GEM
     byebug (9.0.6)
     case_transform (0.2)
       activesupport
+    coderay (1.1.1)
     concurrent-ruby (1.0.4)
-    database_rewinder (0.8.0)
+    database_cleaner (1.5.3)
     debug_inspector (0.0.2)
     diff-lcs (1.3)
     erubis (2.7.0)
@@ -59,6 +60,8 @@ GEM
     factory_girl_rails (4.8.0)
       factory_girl (~> 4.8.0)
       railties (>= 3.0.0)
+    faker (1.7.3)
+      i18n (~> 0.5)
     ffi (1.9.17)
     foreman (0.83.0)
       thor (~> 0.19.1)
@@ -90,6 +93,10 @@ GEM
     nio4r (1.2.1)
     nokogiri (1.7.0.1)
       mini_portile2 (~> 2.1.0)
+    pry (0.10.4)
+      coderay (~> 1.1.0)
+      method_source (~> 0.8.1)
+      slop (~> 3.4)
     puma (3.7.0)
     rack (2.0.1)
     rack-cors (0.4.1)
@@ -149,6 +156,7 @@ GEM
       tilt (>= 1.1, < 3)
     shoulda-matchers (3.1.1)
       activesupport (>= 4.0.0)
+    slop (3.6.0)
     spring (2.0.1)
       activesupport (>= 4.2)
     spring-watcher-listen (2.0.1)
@@ -182,20 +190,22 @@ PLATFORMS
   ruby
 
 DEPENDENCIES
-  active_model_serializers
+  active_model_serializers (~> 0.10.0)
   byebug
-  database_rewinder
-  factory_girl_rails
+  database_cleaner
+  factory_girl_rails (~> 4.0)
+  faker
   foreman
   jquery-rails
   listen (~> 3.0.5)
+  pry
   puma (~> 3.0)
   rack-cors
   rails (~> 5.0.1)
   rspec-json_expectations
   rspec-rails (~> 3.5)
   sass-rails (~> 5.0)
-  shoulda-matchers
+  shoulda-matchers (~> 3.1)
   spring
   spring-watcher-listen (~> 2.0.0)
   sqlite3
@@ -204,4 +214,4 @@ DEPENDENCIES
   web-console (>= 3.3.0)
 
 BUNDLED WITH
-   1.14.3
+   1.14.6
diff --git a/app/controllers/api/api_controller.rb b/app/controllers/api/api_controller.rb
index e930bf9..d725680 100644
--- a/app/controllers/api/api_controller.rb
+++ b/app/controllers/api/api_controller.rb
@@ -1,4 +1,6 @@
 module Api
   class ApiController < ActionController::API
+    include Response
+    include ExceptionHandler
   end
 end
diff --git a/app/controllers/api/messages_controller.rb b/app/controllers/api/messages_controller.rb
index 50e6208..adbd579 100644
--- a/app/controllers/api/messages_controller.rb
+++ b/app/controllers/api/messages_controller.rb
@@ -2,41 +2,33 @@ module Api
   class MessagesController < ApiController
     before_action :set_message, only: [:show, :update, :destroy]
 
-    # GET /messages
+    # GET / messages
     def index
       @messages = Message.order(created_at: :asc).all
-
-      render json: @messages
+      json_response(@messages)
     end
 
-    # GET /messages/1
+    # GET / messages / :id
     def show
-      render json: @message
+      json_response(@message)
     end
 
-    # POST /messages
+    # POST / messages
     def create
-      @message = Message.new(message_params)
-
-      if @message.save
-        render json: @message, status: :created, location: [:admin, @message]
-      else
-        render json: @message.errors, status: :unprocessable_entity
-      end
+      @message = Message.create!(message_params)
+      json_response(@message, :created)
     end
 
-    # PATCH/PUT /messages/1
+    # PUT / messages / :id
     def update
-      if @message.update(message_params)
-        render json: @message
-      else
-        render json: @message.errors, status: :unprocessable_entity
-      end
+      @message.update(message_params)
+      head :no_content
     end
 
-    # DELETE /messages/1
+    # DELETE / messages / :id
     def destroy
       @message.destroy
+      head :no_content
     end
 
     private
@@ -47,7 +39,7 @@ def set_message
 
       # Only allow a trusted parameter "white list" through.
       def message_params
-        params.require(:message).permit(:text)
+        params.permit(:text)
       end
   end
 end
diff --git a/app/controllers/concerns/exception_handler.rb b/app/controllers/concerns/exception_handler.rb
new file mode 100644
index 0000000..28d8dd9
--- /dev/null
+++ b/app/controllers/concerns/exception_handler.rb
@@ -0,0 +1,13 @@
+module ExceptionHandler
+  extend ActiveSupport::Concern
+
+  included do
+    rescue_from ActiveRecord::RecordNotFound do |e|
+      json_response({ message: e.message }, :not_found)
+    end
+
+    rescue_from ActiveRecord::RecordInvalid do |e|
+      json_response({ message: e.message }, :unprocessable_entity)
+    end
+  end
+end
diff --git a/app/controllers/concerns/response.rb b/app/controllers/concerns/response.rb
new file mode 100644
index 0000000..cfb0caa
--- /dev/null
+++ b/app/controllers/concerns/response.rb
@@ -0,0 +1,5 @@
+module Response
+  def json_response(object, status = :ok)
+    render json: object, status: status
+  end
+end
diff --git a/app/models/message.rb b/app/models/message.rb
index b2d5fe6..af8dcf5 100644
--- a/app/models/message.rb
+++ b/app/models/message.rb
@@ -1,3 +1,6 @@
 class Message < ApplicationRecord
+  # model association
   has_many :reactions, dependent: :destroy
+  # validation
+  validates_presence_of :text
 end
diff --git a/spec/factories/messages.rb b/spec/factories/messages.rb
new file mode 100644
index 0000000..ec3decd
--- /dev/null
+++ b/spec/factories/messages.rb
@@ -0,0 +1,5 @@
+FactoryGirl.define do
+  factory :message do
+    text { Faker::Lorem.sentences }
+  end
+end
diff --git a/spec/models/message_spec.rb b/spec/models/message_spec.rb
index 57eadc6..ea5439f 100644
--- a/spec/models/message_spec.rb
+++ b/spec/models/message_spec.rb
@@ -1,5 +1,10 @@
 require 'rails_helper'
 
 RSpec.describe Message, type: :model do
-  #pending "add some examples to (or delete) #{__FILE__}"
+  # association test
+  # ensure Message model has a 1:m relationship with the Reaction model
+  it { should have_many(:reactions).dependent(:destroy) }
+  # validation tests
+  # ensure columns text is present before saving
+  it { should validate_presence_of(:text) }
 end
diff --git a/spec/rails_helper.rb b/spec/rails_helper.rb
index 6f1ab14..4f24d6d 100644
--- a/spec/rails_helper.rb
+++ b/spec/rails_helper.rb
@@ -5,7 +5,16 @@
 abort("The Rails environment is running in production mode!") if Rails.env.production?
 require 'spec_helper'
 require 'rspec/rails'
-# Add additional requires below this line. Rails is not loaded until this point!
+# require database cleaner at the top level
+require 'database_cleaner'
+
+# configure shoulda matchers to use rspec as the test framework and full matcher libraries for rails
+Shoulda::Matchers.configure do |config|
+  config.integrate do |with|
+    with.test_framework :rspec
+    with.library :rails
+  end
+end
 
 # Requires supporting ruby files with custom matchers and macros, etc, in
 # spec/support/ and its subdirectories. Files matching `spec/**/*_spec.rb` are
@@ -20,7 +29,7 @@
 # directory. Alternatively, in the individual `*_spec.rb` files, manually
 # require only the support files necessary.
 #
-# Dir[Rails.root.join('spec/support/**/*.rb')].each { |f| require f }
+Dir[Rails.root.join('spec/support/**/*.rb')].each { |f| require f }
 
 # Checks for pending migration and applies them before tests are run.
 # If you are not using ActiveRecord, you can remove this line.
@@ -30,11 +39,28 @@
   # Remove this line if you're not using ActiveRecord or ActiveRecord fixtures
   config.fixture_path = "#{::Rails.root}/spec/fixtures"
 
+  config.include RequestSpecHelper, type: :request
   # If you're not using ActiveRecord, or you'd prefer not to run each of your
   # examples within a transaction, remove the following line or assign false
   # instead of true.
   config.use_transactional_fixtures = true
 
+  # add `FactoryGirl` methods
+  config.include FactoryGirl::Syntax::Methods
+
+  # start by truncating all the tables but then use the faster transaction strategy the rest of the time.
+  config.before(:suite) do
+    DatabaseCleaner.clean_with(:truncation)
+    DatabaseCleaner.strategy = :transaction
+  end
+
+  # start the transaction strategy as examples are run
+  config.around(:each) do |example|
+    DatabaseCleaner.cleaning do
+      example.run
+    end
+  end
+
   # RSpec Rails can automatically mix in different behaviours to your tests
   # based on their file location, for example enabling you to call `get` and
   # `post` in specs under `spec/controllers`.
diff --git a/spec/requests/messages_spec.rb b/spec/requests/messages_spec.rb
index b32d9ab..4b19c1b 100644
--- a/spec/requests/messages_spec.rb
+++ b/spec/requests/messages_spec.rb
@@ -1,10 +1,105 @@
 require 'rails_helper'
 
-RSpec.describe "Messages", type: :request do
-  describe "GET /messages" do
-    it "works! (now write some real specs)" do
-      get api_messages_path
+RSpec.describe "Messages API", type: :request do
+  # initialize tests data
+  let!(:messages) { create_list(:message, 10) }
+  let(:message_id) { messages.first.id }
+
+  # test suite for GET / messages
+  describe "GET / messages" do
+    before { get "/api/messages" }
+
+    it "returns status code 200" do
       expect(response).to have_http_status(200)
     end
+
+    it "returns messages" do
+      expect(json).not_to be_empty
+      expect(json.size).to eq(10)
+    end
+  end
+
+  # test suite for GET / messages / :id
+  describe "GET / messages / :id" do
+    before { get "/api/messages/#{message_id}" }
+
+    context "when the record exists" do
+      it "returns status code 200" do
+        expect(response).to have_http_status(200)
+      end
+
+      it "returns the message" do
+        expect(json).not_to be_empty
+        expect(json['id']).to eq(message_id)
+      end
+    end
+
+    context "when the record does not exist" do
+      let(:message_id) { 100 }
+
+      it "returns status code 404" do
+        expect(response).to have_http_status(404)
+      end
+
+      it "returns a not found message" do
+        expect(response.body).to match(/Couldn't find Message/)
+      end
+    end
+  end
+
+  # test suite for POST / messages
+  describe "POST / messages" do
+    let(:valid_attributes) { { text: "Text" } }
+    let(:invalid_attributes) { {} }
+
+    context "when the request is valid" do
+      before { post "/api/messages", params: valid_attributes }
+
+      it "returns status code 201" do
+        expect(response).to have_http_status(201)
+      end
+
+      it "creates a message" do
+        expect(json['text']).to eq("Text")
+      end
+    end
+
+    describe "when the request is invalid" do
+      before { post "/api/messages", params: invalid_attributes }
+
+      it "returns status code 422" do
+        expect(response).to have_http_status(422)
+      end
+
+      it "returns a validation failure message" do
+        expect(response.body).to match(/Validation failed: Text can't be blank/)
+      end
+    end
+  end
+
+  # test suite for PUT / messages / :id
+  describe "PUT / messages / :id" do
+    let(:valid_attributes) { { text: "Text" } }
+
+    context "when the record exists" do
+      before { put "/api/messages/#{message_id}", params: valid_attributes }
+
+      it "returns status code 204" do
+        expect(response).to have_http_status(204)
+      end
+
+      it "updates the record" do
+        expect(response.body).to be_empty
+      end
+    end
+  end
+
+  # test suite for DELETE / messages / :id
+  describe "DELETE / messages / :id" do
+    before { delete "/api/messages/#{message_id}" }
+
+    it "returns status code 204" do
+      expect(response).to have_http_status(204)
+    end
   end
 end
diff --git a/spec/support/request_spec_helper.rb b/spec/support/request_spec_helper.rb
new file mode 100644
index 0000000..6d493ba
--- /dev/null
+++ b/spec/support/request_spec_helper.rb
@@ -0,0 +1,5 @@
+module RequestSpecHelper
+  def json
+    JSON.parse(response.body)
+  end
+end