diff --git a/Gemfile b/Gemfile
index 342acdd559..6e302d8def 100644
--- a/Gemfile
+++ b/Gemfile
@@ -4,3 +4,4 @@ gem 'cane'
 gem 'reek'
 gem 'rake'
 gem 'rspec'
+gem 'simplecov', require: false, group: :test
diff --git a/Gemfile.lock b/Gemfile.lock
new file mode 100644
index 0000000000..1b921dde78
--- /dev/null
+++ b/Gemfile.lock
@@ -0,0 +1,50 @@
+GEM
+  remote: https://rubygems.org/
+  specs:
+    ast (2.4.2)
+    cane (3.0.0)
+      parallel
+    diff-lcs (1.5.0)
+    docile (1.4.0)
+    kwalify (0.7.2)
+    parallel (1.22.1)
+    parser (3.1.2.0)
+      ast (~> 2.4.1)
+    rainbow (3.1.1)
+    rake (13.0.6)
+    reek (6.1.1)
+      kwalify (~> 0.7.0)
+      parser (~> 3.1.0)
+      rainbow (>= 2.0, < 4.0)
+    rspec (3.11.0)
+      rspec-core (~> 3.11.0)
+      rspec-expectations (~> 3.11.0)
+      rspec-mocks (~> 3.11.0)
+    rspec-core (3.11.0)
+      rspec-support (~> 3.11.0)
+    rspec-expectations (3.11.0)
+      diff-lcs (>= 1.2.0, < 2.0)
+      rspec-support (~> 3.11.0)
+    rspec-mocks (3.11.1)
+      diff-lcs (>= 1.2.0, < 2.0)
+      rspec-support (~> 3.11.0)
+    rspec-support (3.11.0)
+    simplecov (0.21.2)
+      docile (~> 1.1)
+      simplecov-html (~> 0.11)
+      simplecov_json_formatter (~> 0.1)
+    simplecov-html (0.12.3)
+    simplecov_json_formatter (0.1.4)
+
+PLATFORMS
+  x86_64-darwin-21
+
+DEPENDENCIES
+  cane
+  rake
+  reek
+  rspec
+  simplecov
+
+BUNDLED WITH
+   2.3.13
diff --git a/lib/all_items_test_file.csv b/lib/all_items_test_file.csv
new file mode 100644
index 0000000000..a626a97a43
--- /dev/null
+++ b/lib/all_items_test_file.csv
@@ -0,0 +1,1367 @@
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+ 1800,
+ 1200,
+ 6999,
+ 4000,
+ 13000,
+ 2500,
+ 795,
+ 13000,
+ 3000,
+ 1200,
+ 25000,
+ 500,
+ 25000,
+ 1000,
+ 1199,
+ 2500,
+ 10000,
+ 1500,
+ 5000,
+ 4500,
+ 1000,
+ 9500,
+ 1200,
+ 999,
+ 7500,
+ 3000,
+ 2000,
+ 1000,
+ 2750,
+ 2999,
+ 6100,
+ 25000,
+ 3800
diff --git a/lib/customer.rb b/lib/customer.rb
new file mode 100644
index 0000000000..3f1566f244
--- /dev/null
+++ b/lib/customer.rb
@@ -0,0 +1,10 @@
+class Customer
+	attr_reader :id, :first_name, :last_name, :created_at, :updated_at
+	def initialize(data)
+		@id = data[:id]
+		@first_name = data[:first_name]
+		@last_name = data[:last_name]
+		@created_at = data[:created_at]
+		@updated_at = data[:updated_at]
+	end
+end
diff --git a/lib/invoice.rb b/lib/invoice.rb
new file mode 100644
index 0000000000..b4c6ddf034
--- /dev/null
+++ b/lib/invoice.rb
@@ -0,0 +1,19 @@
+class Invoice
+
+  attr_reader :id,
+              :customer_id,
+              :created_at,
+              :merchant_id
+
+  attr_accessor :status,
+                :updated_at
+
+  def initialize(data)
+    @id           = data[:id]
+    @customer_id  = data[:customer_id]
+    @status       = data[:status]
+    @created_at   = data[:created_at]
+    @updated_at   = data[:updated_at]
+    @merchant_id  = data[:merchant_id]
+  end
+end
diff --git a/lib/invoice_item.rb b/lib/invoice_item.rb
new file mode 100644
index 0000000000..f0979cba7b
--- /dev/null
+++ b/lib/invoice_item.rb
@@ -0,0 +1,24 @@
+class InvoiceItem
+attr_reader :id,
+            :item_id,
+            :invoice_id,
+            :created_at,
+            :unit_price_to_dollars
+
+attr_accessor :quantity,
+              :unit_price,
+              :updated_at
+
+  def initialize(data)
+    @id = data[:id]
+    @item_id = data[:item_id]
+    @invoice_id = data[:invoice_id]
+    @quantity = data[:quantity]
+    @unit_price = data[:unit_price]
+    @created_at = data[:created_at]
+    @updated_at = data[:updated_at]
+    @unit_price_to_dollars = @unit_price.to_f
+  end
+
+
+end
diff --git a/lib/invoice_item_repository.rb b/lib/invoice_item_repository.rb
new file mode 100644
index 0000000000..17ad9a5df0
--- /dev/null
+++ b/lib/invoice_item_repository.rb
@@ -0,0 +1,66 @@
+require 'CSV'
+require 'BigDecimal'
+require_relative './invoice_item.rb'
+
+class InvoiceItemRepository
+  attr_reader :all
+  def initialize(invoice_item_path)
+    @invoice_item_path = invoice_item_path
+    @all = []
+
+    CSV.foreach(@invoice_item_path, headers: true, header_converters: :symbol) do |row|
+    @all << InvoiceItem.new({
+      :id => row[:id],
+      :item_id => row[:item_id],
+      :invoice_id => row[:invoice_id],
+      :quantity => row[:quantity],
+      :unit_price => row[:unit_price],
+      :created_at => row[:created_at],
+      :updated_at => row[:updated_at],
+      :unit_price => row[:unit_price]
+      })
+		end
+
+  end
+
+  def find_by_id(id)
+		@all.find do |invoice_item|
+			invoice_item.id.to_i == id
+		end
+	end
+
+  def find_all_by_item_id(item_id)
+		@all.find_all do |invoice_item|
+			invoice_item.item_id == item_id
+		end
+	end
+
+  def find_all_by_invoice_id(invoice_id)
+		@all.find_all do |invoice_item|
+			invoice_item.invoice_id.to_i == invoice_id
+		end
+	end
+
+  def create(new_invoice_attributes)
+    new_id = @all.last.id.to_i + 1
+    new_attribute = new_invoice_attributes
+    @all << InvoiceItem.new(:id => new_id.to_s, :item_id => new_attribute[:item_id], :invoice_id =>
+    new_attribute[:invoice_id], :unit_price => new_attribute[:unit_price], :quantity => new_attribute[:quantity], :created_at => Time.now, :updated_at => Time.now)
+    return @all.last
+
+  end
+
+  def update(id, attributes)
+		updated_item = find_by_id(id)
+		updated_item.quantity = attributes[:quantity]
+		updated_item.unit_price = attributes[:unit_price]
+		updated_item.updated_at = Time.now
+	end
+
+  def delete(id)
+		removed_item = find_by_id(id)
+    @all.delete(removed_item)
+	end
+
+
+end
diff --git a/lib/invoice_repository.rb b/lib/invoice_repository.rb
new file mode 100644
index 0000000000..ff6deb3606
--- /dev/null
+++ b/lib/invoice_repository.rb
@@ -0,0 +1,64 @@
+require 'CSV'
+require "BigDecimal"
+require_relative'./invoice.rb'
+class InvoiceRepository
+  attr_reader :all
+
+  def initialize(invoice_path)
+    @invoice_path = invoice_path
+    @all = []
+
+    CSV.foreach(@invoice_path, headers: true, header_converters: :symbol) do |row|
+    @all << Invoice.new({
+      :id => row[:id],
+      :customer_id => row[:customer_id],
+      :status => row[:status],
+      :created_at => row[:created_at],
+      :updated_at => row[:updated_at],
+      :merchant_id => row[:merchant_id]})
+    end
+  end
+
+  def find_by_id(id)
+    @all.find do |invoice|
+      invoice.id.to_i == id
+    end
+  end
+
+  def find_all_by_customer_id(customer_id)
+    @all.find_all do |invoice|
+      customer_id.to_i == invoice.customer_id.to_i
+    end
+  end
+
+  def find_all_by_merchant_id(merchant_id)
+    @all.find_all do |invoice|
+      merchant_id.to_i == invoice.merchant_id.to_i
+    end
+  end
+
+  def find_all_by_status(status)
+    @all.find_all do |invoice|
+      status == invoice.status
+    end
+  end
+
+  def create(new_invoice_attributes)
+    new_id = @all.last.id.to_i + 1
+    new_attribute = new_invoice_attributes
+    @all << Invoice.new(:id => new_id.to_s, :customer_id => new_attribute[:customer_id], :merchant_id =>
+    new_attribute[:merchant_id], :status => "pending", :created_at => Time.now, :updated_at => Time.now)
+    return @all.last
+  end
+
+  def update(id, attributes)
+    updated_item = find_by_id(id)
+    updated_item.status = attributes[:status]
+    updated_item.updated_at = Time.now
+  end
+
+  def delete(id)
+    removed_item = find_by_id(id)
+    @all.delete(removed_item)
+  end
+end
diff --git a/lib/item.rb b/lib/item.rb
new file mode 100644
index 0000000000..3b3b8e535e
--- /dev/null
+++ b/lib/item.rb
@@ -0,0 +1,28 @@
+
+require 'CSV'
+
+class Item
+	attr_reader :id,
+							:created_at,
+							:merchant_id
+
+	attr_accessor :name,
+								:description,
+								:unit_price,
+								:updated_at
+
+	def initialize(data)
+		@id = data[:id]
+		@name = data[:name]
+		@description = data[:description]
+		@unit_price = data[:unit_price]
+		@created_at = data[:created_at]
+		@updated_at = data[:updated_at]
+		@merchant_id = data[:merchant_id]
+	end
+
+	def unit_price_to_dollars
+		@unit_price.to_f
+	end
+
+end
diff --git a/lib/item_repository.rb b/lib/item_repository.rb
new file mode 100644
index 0000000000..ce2cdd615a
--- /dev/null
+++ b/lib/item_repository.rb
@@ -0,0 +1,79 @@
+require 'CSV'
+require "BigDecimal"
+require_relative'./item.rb'
+
+class ItemRepository
+	attr_reader :all
+	def initialize(items_path)
+		@items_path = items_path
+		@all = []
+
+		CSV.foreach(@items_path, headers: true, header_converters: :symbol) do |row|
+    @all << Item.new({
+			:id => row[:id],
+			:name => row[:name],
+			:description => row[:description],
+			:unit_price => row[:unit_price],
+			:created_at => row[:created_at],
+			:updated_at => row[:updated_at],
+			:merchant_id => row[:merchant_id]})
+		end
+	end
+
+	def find_by_id(id)
+		@all.find do |item|
+			item.id.to_i == id
+		end
+	end
+
+	def find_by_name(name)
+		@all.find do |item|
+			item.name.downcase.include?(name.downcase)
+		end
+	end
+
+	def find_all_with_description(description)
+		@all.find_all do |item|
+			item.description.downcase.include?(description.downcase)
+		end
+	end
+
+	def find_all_by_price(unit_price)
+		@all.find_all do |item|
+			item.unit_price == unit_price
+		end
+	end
+
+	def find_all_by_price_in_range(range)
+		@all.find_all do |item|
+			(range.min..range.max).include?(item.unit_price.to_i)
+		end
+	end
+
+	def find_all_by_merchant_id(merchant_id)
+		@all.find_all do |item|
+			merchant_id.to_i == item.merchant_id.to_i
+		end
+	end
+
+	def create(attributes)
+		new_id = @all.last.id.to_i + 1
+		new_attribute = attributes
+		@all << Item.new(:id => new_id.to_s, :name => new_attribute[:name], :unit_price =>
+		new_attribute[:unit_price], :description => new_attribute[:description], :created_at => Time.now)
+		return @all.last
+	end
+
+	def update(id, attributes)
+		updated_item = find_by_id(id)
+		updated_item.name = attributes[:name]
+		updated_item.unit_price = attributes[:unit_price]
+		updated_item.description = attributes[:description]
+		updated_item.updated_at = Time.now
+	end
+
+	def delete(id)
+		removed_item = find_by_id(id)
+    @all.delete(removed_item)
+	end
+end
diff --git a/lib/merchant.rb b/lib/merchant.rb
new file mode 100644
index 0000000000..44f52caf76
--- /dev/null
+++ b/lib/merchant.rb
@@ -0,0 +1,10 @@
+class Merchant
+  attr_reader :id
+  attr_accessor :name
+
+  def initialize(data)
+    @id = data[:id]
+    @name = data[:name]
+  end
+
+end
diff --git a/lib/merchant_repository.rb b/lib/merchant_repository.rb
new file mode 100644
index 0000000000..8c2291cd5f
--- /dev/null
+++ b/lib/merchant_repository.rb
@@ -0,0 +1,51 @@
+require 'CSV'
+require_relative './merchant.rb'
+class MerchantRepository
+  attr_reader :all
+  def initialize(file_path)
+    @file_path = file_path
+    @all = []
+
+    CSV.foreach(@file_path, headers: true, header_converters: :symbol) do |row|
+    @all << Merchant.new({:id => row[:id], :name => row[:name]})
+
+    end
+    
+  end
+
+  def find_by_id(id)
+    @all.find do |merchant|
+      merchant.id.to_i == id
+    end
+  end
+
+  def find_by_name(name)
+    @all.find do |merchant|
+      merchant.name.downcase.include?(name.downcase)
+    end
+  end
+
+  def find_all_by_name(name_fragment)
+    @all.find_all do |merchant|
+      merchant.name.downcase.include?(name_fragment.downcase)
+    end
+  end
+
+  def create(attribute)
+    new_id = @all.last.id.to_i + 1
+    new_attribute = attribute
+    @all << Merchant.new(:id => new_id.to_s, :name => new_attribute)
+    return @all.last
+  end
+
+  def update(id, attributes)
+    renamed_merchant = find_by_id(id)
+    renamed_merchant.name = attributes
+  end
+
+  def delete(id)
+    removed_merchant = find_by_id(id)
+    @all.delete(removed_merchant)
+  end
+
+end
diff --git a/lib/sales_analyst.rb b/lib/sales_analyst.rb
new file mode 100644
index 0000000000..5994f0e091
--- /dev/null
+++ b/lib/sales_analyst.rb
@@ -0,0 +1,201 @@
+require_relative "./sales_engine"
+require_relative "./item_repository"
+require_relative "./merchant_repository"
+require "bigdecimal"
+require "bigdecimal/util"
+require "date"
+
+class SalesAnalyst
+	attr_reader :items, :merchants, :invoices
+	def initialize(items, merchants, invoices)
+		@items = items
+		@merchants = merchants
+		@invoices = invoices
+	end
+
+	def average_items_per_merchant
+		average_number = items.all.count.to_f / merchants.all.count.to_f
+		return average_number.round(2)
+	end
+
+	def items_by_merchant
+		items_per_merchant = Hash.new(0)
+		merchant_ids = items.all.map {|item| item.merchant_id}
+		merchant_ids.each do |id|
+			items_per_merchant[id] += 1
+		end
+		return items_per_merchant
+	end
+
+	def average_items_per_merchant_standard_deviation
+		set = items_by_merchant.values
+		mean = average_items_per_merchant
+    sums = set.sum { |num| (num - mean)**2 }
+    std_dev = Math.sqrt(sums / (set.length - 1).to_f)
+    std_dev.round(2)
+	end
+
+	def merchants_with_high_item_count
+		standard_deviation = average_items_per_merchant_standard_deviation
+		mean_and_standard_dev = standard_deviation + average_items_per_merchant
+		merchants_with_high_sales = []
+		items_by_merchant.each_pair do |merchant, items|
+			merchants_with_high_sales << merchant if items > mean_and_standard_dev
+		end
+		return merchants_with_high_sales
+	end
+
+	def average_item_price_for_merchant(merchant_id)
+		find_merchant = @items.find_all_by_merchant_id(merchant_id)
+		items_sum = find_merchant.sum do |item|
+			item.unit_price.to_f
+		end
+		(items_sum / find_merchant.count).to_d(3)
+	end
+
+	def average_average_price_per_merchant
+		merchant_price_sums = []
+		merchant_ids = items.all.map {|item| item.merchant_id.to_i}
+		merchant_ids.each do |id|
+			merchant_price_sums	<< average_item_price_for_merchant(id).to_f
+		end
+		(merchant_price_sums.sum / merchant_price_sums.size).to_d(3)
+	end
+
+	def standard_deviation(values, mean)
+    sums = values.sum { |value| (value - mean)**2 }
+    std_dev = Math.sqrt(sums / (values.length - 1).to_f)
+    std_dev.round(2)
+  end
+
+	def golden_items
+		array_of_all_prices = @items.all.map {|item| item.unit_price.to_i}
+		set = array_of_all_prices
+		mean = array_of_all_prices.sum / array_of_all_prices.size
+		std_dev = standard_deviation(set, mean)
+		minimum_golden_price = mean += (2 * std_dev)
+		items.all.find_all{ |item| item.unit_price.to_i > minimum_golden_price }
+	end
+
+	def average_invoices_per_merchant
+		(@invoices.all.size / @merchants.all.size.to_f).round(2)
+	end
+
+	def average_invoices_per_merchant_standard_deviation
+		set = invoices_by_merchant.values
+		avg = average_invoices_per_merchant
+		standard_deviation(set, avg)
+	end
+
+	def invoices_by_merchant
+		invoices_per_merchant = Hash.new(0)
+		merchant_ids = invoices.all.map {|invoice| invoice.merchant_id}
+		merchant_ids.each do |id|
+			invoices_per_merchant[id] += 1
+		end
+		return invoices_per_merchant
+	end
+
+	def merchant_z_score(invoice_count)
+		mean = average_invoices_per_merchant
+		std_dev = average_invoices_per_merchant_standard_deviation
+		z_score = (invoice_count - mean) / std_dev
+		return z_score.round(2)
+	end
+
+	def merchants_by_zscore
+		merchant_by_z_score = Hash.new
+		invoices_by_merchant.each do |merchant, invoice_count|
+			merchant_by_z_score[merchant] = merchant_z_score(invoice_count)
+		end
+		return merchant_by_z_score
+	end
+
+	def top_merchants_by_invoice_count
+		top_merchants = []
+		merchants_by_zscore.each do |merchants, zscore|
+		top_merchants	<< merchants if zscore > 2
+		end
+		return top_merchants
+	end
+
+	def bottom_merchants_by_invoice_count
+		bottom_merchants = []
+		merchants_by_zscore.each do |merchants, zscore|
+		bottom_merchants	<< merchants if zscore < 2
+		end
+		return bottom_merchants
+	end
+
+	def top_days_by_invoice_count
+		top_days = []
+		weekday_by_zscore.each do |day, zscore|
+		top_days	<< day if zscore > 1
+		end
+		return top_days
+	end
+
+	def date_to_day(date)
+		weekday = Date.parse(date)
+		weekday_num = weekday.wday
+		weekday_name = Date::DAYNAMES[weekday_num]
+		return weekday_name
+	end
+
+	def invoices_by_day
+		invoices_per_day = Hash.new(0)
+		invoice_dates = invoices.all.map {|invoice| invoice.created_at}
+		invoice_dates.each do |date|
+			invoices_per_day[date_to_day(date)] += 1
+		end
+		return invoices_per_day
+	end
+
+	def average_invoices_per_day
+	 invoices_by_day.values.sum / invoices_by_day.count
+	end
+
+	def average_invoices_per_day_standard_deviation
+		set = invoices_by_day.values
+		avg = average_invoices_per_day
+		standard_deviation(set, avg)
+	end
+
+	def weekday_by_zscore
+		day_by_z_score = Hash.new
+		invoices_by_day.each do |day, invoice_count|
+			day_by_z_score[day] = weekday_z_score(invoice_count)
+		end
+		return day_by_z_score
+	end
+
+	def weekday_z_score(invoice_count)
+		mean = average_invoices_per_day
+		std_dev = average_invoices_per_day_standard_deviation
+		z_score = (invoice_count - mean) / std_dev
+		return z_score.round(2)
+	end
+
+	def invoice_status(status)
+		status_percentage = ((invoice_by_status_count[(status)].to_f / invoice_by_status_count.values.sum.to_f)*100)
+		return status_percentage.round(2)
+	end
+
+	def invoice_by_status
+		invoices_per_status = Hash.new
+		invoices.all.each do |invoice|
+			invoices_per_status[invoice.id] = invoice.status
+		end
+		return invoices_per_status
+	end
+
+	def invoice_by_status_count
+		status_count = Hash.new(0)
+		invoice_by_status.each do |id, status|
+			status_count[status.to_sym] += 1
+		end
+		return status_count
+	end
+
+
+end
diff --git a/lib/sales_engine.rb b/lib/sales_engine.rb
new file mode 100644
index 0000000000..cb02716f10
--- /dev/null
+++ b/lib/sales_engine.rb
@@ -0,0 +1,18 @@
+class SalesEngine
+  attr_reader :items,
+              :merchants,
+              :invoices,
+              :analyst
+
+  def initialize(items_path, merchants_path, invoice_path)
+    @items      = ItemRepository.new(items_path)
+    @merchants  = MerchantRepository.new(merchants_path)
+    @invoices   = InvoiceRepository.new(invoice_path)
+    @analyst    = SalesAnalyst.new(items, merchants, invoices)
+  end
+
+  def self.from_csv(data)
+    return SalesEngine.new(data[:items], data[:merchants], data[:invoices])
+  end
+
+end
diff --git a/test/.gitignore b/spec/.gitignore
similarity index 100%
rename from test/.gitignore
rename to spec/.gitignore
diff --git a/spec/customer_spec.rb b/spec/customer_spec.rb
new file mode 100644
index 0000000000..50689b4f71
--- /dev/null
+++ b/spec/customer_spec.rb
@@ -0,0 +1,79 @@
+require './lib/customer'
+require 'time'
+
+RSpec.describe Customer do
+
+	it 'exists' do
+		c = Customer.new({
+  	:id => 6,
+  	:first_name => "Joan",
+  	:last_name => "Clarke",
+  	:created_at => Time.now,
+  	:updated_at => Time.now
+		})
+
+		expect(c).to be_an_instance_of Customer
+	end
+
+	it 'can return the customer id' do
+		c = Customer.new({
+		:id => 6,
+		:first_name => "Joan",
+		:last_name => "Clarke",
+		:created_at => Time.now,
+		:updated_at => Time.now
+		})
+
+		expect(c.id).to eq(6)
+
+	end
+
+	it 'can return the customers first name' do
+		c = Customer.new({
+		:id => 6,
+		:first_name => "Joan",
+		:last_name => "Clarke",
+		:created_at => Time.now,
+		:updated_at => Time.now
+		})
+
+		expect(c.first_name).to eq("Joan")
+	end
+
+	it 'can return the customers last name' do
+		c = Customer.new({
+		:id => 6,
+		:first_name => "Joan",
+		:last_name => "Clarke",
+		:created_at => Time.now,
+		:updated_at => Time.now
+		})
+
+		expect(c.last_name).to eq("Clarke")
+
+	end
+
+	it 'can return the time the customers profile was created' do
+		c = Customer.new({
+		:id => 6,
+		:first_name => "Joan",
+		:last_name => "Clarke",
+		:created_at => Time.now.round,
+		:updated_at => Time.now.round
+		})
+
+		expect(c.created_at).to eq(Time.now.round)
+	end
+
+	it 'can return the time the customers profile was updated' do
+		c = Customer.new({
+		:id => 6,
+		:first_name => "Joan",
+		:last_name => "Clarke",
+		:created_at => Time.now.round,
+		:updated_at => Time.now.round
+		})
+
+		expect(c.updated_at).to eq(Time.now.round)
+	end
+end
diff --git a/spec/invoice_item_repository_spec.rb b/spec/invoice_item_repository_spec.rb
new file mode 100644
index 0000000000..22471d300e
--- /dev/null
+++ b/spec/invoice_item_repository_spec.rb
@@ -0,0 +1,92 @@
+require './lib/invoice_item_repository'
+require 'BigDecimal'
+require 'CSV'
+
+
+RSpec.describe InvoiceItemRepository do
+  it 'exists' do
+    invoice_items = './data/invoice_items.csv'
+    ii_repo = InvoiceItemRepository.new(invoice_items)
+    expect(ii_repo).to be_a(InvoiceItemRepository)
+  end
+
+  it 'returns an array of all known InvoiceItem instances' do
+    invoice_items = './data/invoice_items.csv'
+    ii_repo = InvoiceItemRepository.new(invoice_items)
+    expect(ii_repo.all).to be_a(Array)
+  end
+
+    it 'return the amount of all known invoice_items instances' do
+      invoice_items = './data/invoice_items.csv'
+      ii_repo = InvoiceItemRepository.new(invoice_items)
+      expect(ii_repo.all.count).to eq(21830)
+    end
+
+    it 'can find all by id' do
+      invoice_items = './data/invoice_items.csv'
+      ii_repo = InvoiceItemRepository.new(invoice_items)
+
+      expect(ii_repo.find_by_id(1)).to be_an_instance_of(InvoiceItem)
+      expect(ii_repo.find_by_id(999991)).to eq(nil)
+    end
+
+    it 'can find all by item_id' do
+      invoice_items = './data/invoice_items.csv'
+      ii_repo = InvoiceItemRepository.new(invoice_items)
+
+      expect(ii_repo.find_all_by_item_id(263519844)).to be_an_instance_of(Array)
+      expect(ii_repo.find_all_by_item_id(999991)).to eq([])
+    end
+
+    it 'can find all by invoice_id' do
+    invoice_items = './data/invoice_items.csv'
+    ii_repo = InvoiceItemRepository.new(invoice_items)
+
+    expect(ii_repo.find_all_by_invoice_id(1)).to be_instance_of(Array)
+    expect(ii_repo.find_all_by_invoice_id(999991)).to eq([])
+    expect(ii_repo.find_all_by_invoice_id(1).size).to eq(8)
+  end
+
+  it 'can create attributes' do
+    invoice_items = './data/invoice_items.csv'
+    ii_repo = InvoiceItemRepository.new(invoice_items)
+    new_item_attributes = {:item_id => "2635999123", :invoice_id => "4986",
+    :unit_price => "99999",:quantity => "9"}
+
+    new_item = (ii_repo.create(new_item_attributes))
+
+    expect(new_item.id).to eq("21831")
+    expect(new_item.item_id).to eq("2635999123")
+    expect(new_item.invoice_id).to eq("4986")
+    expect(new_item.unit_price).to eq("99999")
+    expect(new_item.quantity).to eq("9")
+    expect(new_item.created_at).to be_an_instance_of(Time)
+    expect(ii_repo.find_by_id(21831)).to be_an_instance_of(InvoiceItem)
+  end
+
+  it 'can update Invoice items with attributes' do
+    invoice_items = './data/invoice_items.csv'
+    ii_repo = InvoiceItemRepository.new(invoice_items)
+
+    expect(ii_repo.find_by_id(10).quantity).to eq("4")
+    expect(ii_repo.find_by_id(10).unit_price).to eq("1859")
+
+    new_test_attributes = {:quantity => "99", :unit_price => "2000", :updated_at => "1"}
+    ii_repo.update(10, new_test_attributes)
+
+    expect(ii_repo.find_by_id(10).quantity).to eq("99")
+    expect(ii_repo.find_by_id(10).unit_price).to eq("2000")
+    expect(ii_repo.find_by_id(10).updated_at).to be_an_instance_of(Time)
+
+  end
+
+    it 'can delete the InvoiceItem instance with the corresponding id' do
+      invoice_items = './data/invoice_items.csv'
+      ii_repo = InvoiceItemRepository.new(invoice_items)
+
+      expect(ii_repo.find_by_id(10)).to be_a(InvoiceItem)
+      ii_repo.delete(10)
+      expect(ii_repo.find_by_id(10)).to eq(nil)
+    end
+
+end
diff --git a/spec/invoice_item_spec.rb b/spec/invoice_item_spec.rb
new file mode 100644
index 0000000000..754143af5c
--- /dev/null
+++ b/spec/invoice_item_spec.rb
@@ -0,0 +1,50 @@
+require "./lib/invoice_item"
+require "bigdecimal"
+require "Rspec"
+
+RSpec.describe InvoiceItem do
+
+
+  it 'exists' do
+    data = ({:id => 1,
+    :item_id => 263519844,
+    :invoice_id => 1,
+    :quantity => 5,
+    :unit_price  => 13635,
+    :created_at  => Time.now,
+    :updated_at  => Time.now})
+
+    invoiceitem = InvoiceItem.new(data)
+    expect(invoiceitem).to be_an_instance_of(InvoiceItem)
+  end
+
+  it "can return the details of an invoice id" do
+    data = ({:id => 1,
+    :item_id => 263519844,
+    :invoice_id => 1,
+    :quantity => 5,
+    :unit_price  => 13635,
+    :created_at  => Time.now.round,
+    :updated_at  => Time.now.round})
+
+    invoiceitem = InvoiceItem.new(data)
+    expect(invoiceitem.id).to eq(1)
+    expect(invoiceitem.item_id).to eq(263519844)
+    expect(invoiceitem.quantity).to eq(5)
+    expect(invoiceitem.created_at).to eq(Time.now.round)
+    expect(invoiceitem.updated_at).to eq(Time.now.round)
+  end
+
+  it "can return the unit price as a float" do
+    data = ({:id => 1,
+    :item_id => 263519844,
+    :invoice_id => 1,
+    :quantity => 5,
+    :unit_price  => 13635,
+    :created_at  => Time.now,
+    :updated_at  => Time.now})
+
+    invoiceitem = InvoiceItem.new(data)
+    expect(invoiceitem.unit_price_to_dollars).to eq(13635.0)
+  end
+end
diff --git a/spec/invoice_repository_spec.rb b/spec/invoice_repository_spec.rb
new file mode 100644
index 0000000000..7f1e4d1b8f
--- /dev/null
+++ b/spec/invoice_repository_spec.rb
@@ -0,0 +1,84 @@
+require './lib/item.rb'
+require './lib/item_repository'
+require './lib/merchant_repository'
+require './lib/merchant'
+require './lib/invoice'
+require './lib/invoice_repository'
+
+RSpec.describe InvoiceRepository do
+
+  it "exists" do
+    invoice_repo = InvoiceRepository.new('./data/invoices.csv')
+    expect(invoice_repo).to be_a(InvoiceRepository)
+  end
+
+  it "can return an array of all invoices" do
+    invoice_repo = InvoiceRepository.new('./data/invoices.csv')
+    expect(invoice_repo.all.count).to eq(4985)
+  end
+
+  it "can find a invoice by an id" do
+    invoice_repo = InvoiceRepository.new('./data/invoices.csv')
+    expect(invoice_repo.find_by_id(1)).to be_a(Invoice)
+    expect(invoice_repo.find_by_id(123542345293423)).to eq(nil)
+  end
+
+  it "can find all invoices by a specific customer id" do
+    invoice_repo = InvoiceRepository.new('./data/invoices.csv')
+    expect(invoice_repo.find_all_by_customer_id(1)).to be_instance_of(Array)
+    expect(invoice_repo.find_all_by_customer_id(1).length).to eq(8)
+    expect(invoice_repo.find_all_by_customer_id(12345678910112)).to eq([])
+  end
+
+  it "can find all invoices by a matching merchant id" do
+    invoice_repo = InvoiceRepository.new('./data/invoices.csv')
+    expect(invoice_repo.find_all_by_merchant_id(12335938)).to be_instance_of(Array)
+    expect(invoice_repo.find_all_by_merchant_id(12335938).length).to eq(16)
+    expect(invoice_repo.find_all_by_merchant_id(12345678910112)).to eq([])
+  end
+
+  it 'can find all invoices by a matching status' do
+    invoice_repo = InvoiceRepository.new('./data/invoices.csv')
+    expect(invoice_repo.find_all_by_status("shipped")).to be_a(Array)
+    expect(invoice_repo.find_all_by_status("returned")).to be_a(Array)
+    expect(invoice_repo.find_all_by_status("pending")).to be_a(Array)
+    expect(invoice_repo.find_all_by_status("super cool status")).to eq([])
+  end
+
+  it 'can create an invoice instance with provided attributes' do
+    invoice_repo = InvoiceRepository.new('./data/invoices.csv')
+    new_invoice_attributes = {:customer_id => "1000",
+    :merchant_id => "12334372"}
+    new_invoice = (invoice_repo.create(new_invoice_attributes))
+    expect(new_invoice.customer_id).to eq("1000")
+    expect(new_invoice.merchant_id).to eq("12334372")
+    expect(invoice_repo.find_all_by_merchant_id(12334372)).to be_a(Array)
+  end
+
+  it 'can update an invoices attributes' do
+    invoice_repo = InvoiceRepository.new('./data/invoices.csv')
+    new_invoice_attributes = {:customer_id => "1000",
+    :merchant_id => "12334372"}
+    new_invoice = (invoice_repo.create(new_invoice_attributes))
+
+    expect(invoice_repo.find_by_id(4986).customer_id).to eq("1000")
+    expect(invoice_repo.find_by_id(4986).merchant_id).to eq("12334372")
+    expect(invoice_repo.find_by_id(4986).status).to eq("pending")
+
+    new_test_attributes = {:status => "shipped"}
+    invoice_repo.update(4986, new_test_attributes)
+
+    expect(invoice_repo.find_by_id(4986).customer_id).to eq("1000")
+    expect(invoice_repo.find_by_id(4986).merchant_id).to eq("12334372")
+    expect(invoice_repo.find_by_id(4986).status).to eq("shipped")
+    expect(invoice_repo.find_by_id(4986).updated_at).to be_instance_of(Time)
+  end
+
+  it 'can delete an invoice' do
+    invoice_repo = InvoiceRepository.new('./data/invoices.csv')
+    expect(invoice_repo.find_by_id(4985)).to be_a(Invoice)
+    invoice_repo.delete(4985)
+    expect(invoice_repo.find_by_id(4985)).to eq(nil)
+  end
+
+end
diff --git a/spec/invoice_spec.rb b/spec/invoice_spec.rb
new file mode 100644
index 0000000000..84f543c495
--- /dev/null
+++ b/spec/invoice_spec.rb
@@ -0,0 +1,80 @@
+require './lib/item'
+require 'time'
+require 'bigdecimal'
+require './lib/invoice.rb'
+
+RSpec.describe Invoice do
+
+  it "exists" do
+    inv = Invoice.new({
+     :id              => 6,
+     :customer_id     => 7,
+     :status => "pending",
+     :created_at  => Time.now,
+     :updated_at  => Time.now,
+     :merchant_id => 8})
+
+     	expect(inv).to be_instance_of(Invoice)
+  end
+
+  it "returns the id" do
+    inv = Invoice.new({
+     :id              => 6,
+     :customer_id     => 7,
+     :status => "pending",
+     :created_at  => Time.now,
+     :updated_at  => Time.now,
+     :merchant_id => 8})
+
+     expect(inv.id).to eq(6)
+  end
+
+  it "returns the customer_id" do
+    inv = Invoice.new({
+     :id              => 6,
+     :customer_id     => 7,
+     :status => "pending",
+     :created_at  => Time.now,
+     :updated_at  => Time.now,
+     :merchant_id => 8})
+
+     expect(inv.customer_id).to eq(7)
+  end
+
+  it "returns the merchant_id" do
+    inv = Invoice.new({
+     :id              => 6,
+     :customer_id     => 7,
+     :status => "pending",
+     :created_at  => Time.now,
+     :updated_at  => Time.now,
+     :merchant_id => 8})
+
+     expect(inv.merchant_id).to eq(8)
+   end
+
+   it "returns the status" do
+     inv = Invoice.new({
+      :id              => 6,
+      :customer_id     => 7,
+      :status => "pending",
+      :created_at  => Time.now,
+      :updated_at  => Time.now,
+      :merchant_id => 8})
+
+      expect(inv.status).to eq("pending")
+    end
+
+    it "returns the time updated at and created at" do
+      inv = Invoice.new({
+       :id              => 6,
+       :customer_id     => 7,
+       :status => "pending",
+       :created_at  => Time.now.round,
+       :updated_at  => Time.now.round,
+       :merchant_id => 8})
+
+       expect(inv.created_at).to eq(Time.now.round)
+       expect(inv.updated_at).to eq(Time.now.round)
+     end
+end
diff --git a/spec/item_repository_spec.rb b/spec/item_repository_spec.rb
new file mode 100644
index 0000000000..e421bd199f
--- /dev/null
+++ b/spec/item_repository_spec.rb
@@ -0,0 +1,92 @@
+require './lib/item.rb'
+require './lib/item_repository'
+require './lib/merchant_repository'
+require './lib/merchant'
+
+RSpec.describe ItemRepository do
+  it "exists" do
+    item_repo = ItemRepository.new('./data/items.csv')
+    expect(item_repo).to be_a(ItemRepository)
+  end
+
+  it "can return an array of all known item instances" do
+    item_repo = ItemRepository.new('./data/items.csv')
+    expect(item_repo.all.count).to eq(1367)
+  end
+
+  it "can find item by ID" do
+    item_repo = ItemRepository.new('./data/items.csv')
+    expect(item_repo.find_by_id(263400305)).to be_a(Item)
+    expect(item_repo.find_by_id(12345678910)).to eq(nil)
+  end
+
+  it "can find an item by name" do
+    item_repo = ItemRepository.new('./data/items.csv')
+    expect(item_repo.find_by_name("Free standing Woden letters")).to be_instance_of(Item)
+    expect(item_repo.find_by_name("FREE stANDing wOdeN lEttErs")).to be_instance_of(Item)
+    expect(item_repo.find_by_name("InvalidName")).to eq(nil)
+  end
+
+  it "can return an item by parts of a description" do
+    item_repo = ItemRepository.new('./data/items.csv')
+    expect(item_repo.find_all_with_description("Disney")).to be_instance_of(Array)
+    expect(item_repo.find_all_with_description("dISneY")).to be_instance_of(Array)
+    #This next one was tricky, I had to look through the items.csv, and filter
+    #out anything that wasn't a specific item (lots of pitches, dialogues)
+    expect(item_repo.find_all_with_description("Disney").length).to eq (5)
+    expect(item_repo.find_all_with_description("Thiago")).to eq([])
+  end
+
+  it "can find all items by price" do
+    item_repo = ItemRepository.new('./data/items.csv')
+    expect(item_repo.find_all_by_price("1300")).to be_instance_of(Array)
+    expect(item_repo.find_all_by_price("1300").count).to eq(8)
+    expect(item_repo.find_all_by_price("1,000,000")).to eq([])
+  end
+
+  it "can find all items by price in a range" do
+    item_repo = ItemRepository.new('./data/items.csv')
+    expect(item_repo.find_all_by_price_in_range(1..1400)).to be_instance_of(Array)
+    expect(item_repo.find_all_by_price_in_range(0..0)).to eq([])
+  end
+
+  it "can find all by merchant id" do
+    item_repo = ItemRepository.new('./data/items.csv')
+    merchant_repo = MerchantRepository.new('./data/merchants.csv')
+    expect(item_repo.find_all_by_merchant_id(12334105)).to be_instance_of(Array)
+    expect(item_repo.find_all_by_merchant_id(12334105).length).to eq(3)
+    expect(item_repo.find_all_by_merchant_id(12345678910112)).to eq([])
+  end
+
+  it "can create a new item with provided attributes" do
+    item_repo = ItemRepository.new('./data/items.csv')
+    new_item_attributes = {:name => "Oreos", :description => "a sandwich cookie",
+    :unit_price => "50", }
+    new_item = (item_repo.create(new_item_attributes))
+    expect(new_item.name).to eq("Oreos")
+    expect(new_item.unit_price).to eq("50")
+    expect(new_item.description).to eq("a sandwich cookie")
+    expect(new_item.created_at).to be_instance_of(Time)
+    expect(item_repo.find_by_id(263567475)).to be_a(Item)
+  end
+
+  it "can update an item's attributes" do
+    item_repo = ItemRepository.new('./data/items.csv')
+    expect(item_repo.find_by_id(263567474).name).to eq("Minty Green Knit Crochet Infinity Scarf")
+    expect(item_repo.find_by_id(263567474).description).to eq("- Super Chunky knit infinity scarf\n- Soft mixture of 97% Acrylic and 3% Viscose\n- Beautiful, Warm, and Stylish\n- Very easy to care for\n\nHand wash with cold water and lay flat to dry")
+    expect(item_repo.find_by_id(263567474).unit_price).to eq("3800")
+    new_test_attributes = {:name => "New Test Scarf", :description => "A beautiful testing scarf", :unit_price => "1"}
+    item_repo.update(263567474, new_test_attributes)
+    expect(item_repo.find_by_id(263567474).name).to eq("New Test Scarf")
+    expect(item_repo.find_by_id(263567474).description).to eq("A beautiful testing scarf")
+    expect(item_repo.find_by_id(263567474).unit_price).to eq("1")
+    expect(item_repo.find_by_id(263567474).updated_at).to be_instance_of(Time)
+  end
+
+  it "can delete an item" do
+    item_repo = ItemRepository.new('./data/items.csv')
+    expect(item_repo.find_by_id(263567474)).to be_a(Item)
+    item_repo.delete(263567474)
+    expect(item_repo.find_by_id(263567474)).to eq(nil)
+  end
+end
diff --git a/spec/merchant_repository_spec.rb b/spec/merchant_repository_spec.rb
new file mode 100644
index 0000000000..c0073b4012
--- /dev/null
+++ b/spec/merchant_repository_spec.rb
@@ -0,0 +1,78 @@
+require './lib/merchant.rb'
+require './lib/merchant_repository.rb'
+
+RSpec.describe MerchantRepository do
+  it 'exists' do
+    merchant_repo = MerchantRepository.new('./data/merchants.csv')
+    expect(merchant_repo).to be_a(MerchantRepository)
+  end
+
+  it 'returns an array of all known Merchant instances' do
+    merchant_repo = MerchantRepository.new('./data/merchants.csv')
+    expect(merchant_repo.all.count).to eq(475)
+  end
+
+  it 'can find merchant by ID' do
+    merchant_repo = MerchantRepository.new('./data/merchants.csv')
+    expect(merchant_repo.find_by_id(12334105)).to be_a(Merchant)
+    expect(merchant_repo.find_by_id(12948129048)).to eq(nil)
+  end
+
+  it 'can find merchant by name' do
+    merchant_repo = MerchantRepository.new('./data/merchants.csv')
+    expect(merchant_repo.find_by_name('Shopin1901')).to be_instance_of(Merchant)
+    expect(merchant_repo.find_by_name('sHoPiN1901')).to be_instance_of(Merchant)
+    expect(merchant_repo.find_by_name('InvalidName')).to eq(nil)
+  end
+
+  it 'can find all merchants by name fragment' do
+    merchant_repo = MerchantRepository.new('./data/merchants.csv')
+    merchant_repo.find_all_by_name("mini").each do |merchant|
+      expect merchant.name.include?("mini"). to eq("mini")
+    end
+
+        expect(merchant.name.downcase.include?("mini")).to eq(true)
+        expect(merchant).to be_instance_of(Merchant)
+      end
+    expect(merchant_repo.find_all_by_name('mini')).to be_instance_of(Array)
+
+    merchant_repo.find_all_by_name("MiNi").each   do |merchant|
+        expect(merchant.name.downcase.include?("mini")).to eq(true)
+        expect(merchant).to be_instance_of(Merchant)
+      end
+
+    expect(merchant_repo.find_all_by_name('MiNi')).to be_instance_of(Array)
+    expect(merchant_repo.find_all_by_name('inG')).to be_instance_of(Array)
+    expect(merchant_repo.find_all_by_name('sHoPiN')).to be_instance_of(Array)
+    expect(merchant_repo.find_all_by_name('sHoPiN1901')).to be_instance_of(Array)
+
+    merchant_repo.find_all_by_name("InvalidName").each do |merchant|
+        expect(merchant.name.downcase.include?("invalidname")).to eq(false)
+        expect(merchant).to eq(nil)
+      end
+    expect(merchant_repo.find_all_by_name('InvalidName')).to eq([])
+  end
+
+  it "can create a new merchant instance" do
+    merchant_repo = MerchantRepository.new('./data/merchants.csv')
+    new_merchant = merchant_repo.create("Turing School of Software and Design")
+    expect(new_merchant.name).to eq("Turing School of Software and Design")
+    expect(merchant_repo.find_by_id(12337412)).to be_a(Merchant)
+  end
+
+  it "can update a merchant object" do
+    merchant_repo = MerchantRepository.new('./data/merchants.csv')
+    expect(merchant_repo.find_by_id(12334105).name).to eq("Shopin1901")
+    merchant_repo.update(12334105, "Shopin2022")
+    expect(merchant_repo.find_by_id(12334105).name).to eq("Shopin2022")
+    expect(merchant_repo.find_by_name("Shopin1901")).to eq(nil)
+  end
+
+  it 'can delete a merchant object' do
+    merchant_repo = MerchantRepository.new('./data/merchants.csv')
+    expect(merchant_repo.find_by_id(12334105)).to be_a(Merchant)
+    merchant_repo.delete(12334105)
+    expect(merchant_repo.find_by_id(12334105)).to eq(nil)
+  end
+
+end
diff --git a/spec/merchant_spec.rb b/spec/merchant_spec.rb
new file mode 100644
index 0000000000..6b228668fc
--- /dev/null
+++ b/spec/merchant_spec.rb
@@ -0,0 +1,21 @@
+require './lib/merchant'
+
+RSpec.describe Merchant do
+  it "exists" do
+    merchant = Merchant.new(:id => 1, :name => "Bob's Burgers")
+    expect(merchant).to  be_instance_of (Merchant)
+  end
+
+
+  it "can return a name" do
+    merchant = Merchant.new(:id => 1, :name => "Bob's Burgers")
+
+    expect(merchant.name).to eq("Bob's Burgers")
+  end
+
+	it "can return an id" do
+		merchant = Merchant.new(:id => 1, :name => "Bob's Burgers")
+
+		expect(merchant.id).to eq(1)
+	end
+end
diff --git a/spec/sales_engine_spec.rb b/spec/sales_engine_spec.rb
new file mode 100644
index 0000000000..a100aa1804
--- /dev/null
+++ b/spec/sales_engine_spec.rb
@@ -0,0 +1,48 @@
+require "./lib/sales_engine"
+require "./lib/item_repository"
+require "./lib/merchant_repository"
+require "./lib/invoice_repository"
+
+RSpec.describe SalesEngine do
+  it "exists" do
+    sales_engine = SalesEngine.from_csv({
+      :items => "./data/items.csv",
+      :merchants => "./data/merchants.csv",
+      :invoices => "./data/invoices.csv"
+    })
+    expect(sales_engine).to be_instance_of SalesEngine
+  end
+
+  it "can return an array of all items" do
+    sales_engine = SalesEngine.from_csv({
+      :items => "./data/items.csv",
+      :merchants => "./data/merchants.csv",
+      :invoices => "./data/invoices.csv"
+
+    })
+
+    expect(sales_engine.items).to be_instance_of ItemRepository
+  end
+
+  it "can return an array of all merchants" do
+    sales_engine = SalesEngine.from_csv({
+      :items => "./data/items.csv",
+      :merchants => "./data/merchants.csv",
+      :invoices => "./data/invoices.csv"
+
+    })
+    expect(sales_engine.merchants).to be_instance_of MerchantRepository
+
+  end
+
+  it "can return an array of all merchants" do
+    sales_engine = SalesEngine.from_csv({
+      :items => "./data/items.csv",
+      :merchants => "./data/merchants.csv",
+      :invoices => "./data/invoices.csv"
+
+    })
+    expect(sales_engine.invoices).to be_instance_of InvoiceRepository
+
+  end
+end
diff --git a/spec/spec_helper.rb b/spec/spec_helper.rb
new file mode 100644
index 0000000000..39e075fadc
--- /dev/null
+++ b/spec/spec_helper.rb
@@ -0,0 +1,2 @@
+require 'simplecov'
+SimpleCov.start