added tests for customer model validations

Gemfile

@@ -28,6 +28,7 @@ gem 'puma', '~> 3.7'
 group :development, :test do
   # Call 'byebug' anywhere in the code to stop execution and get a debugger console
   gem 'byebug', platforms: [:mri, :mingw, :x64_mingw]
+  gem 'pry-rails'
 end
 
 group :development do

app/models/customer.rb

@@ -1,3 +1,5 @@
 class Customer < ApplicationRecord
   has_many :rentals
+
+  validates :name, presence: true
 end

config/routes.rb

@@ -1,3 +1,4 @@
 Rails.application.routes.draw do
   # For details on the DSL available within this file, see http://guides.rubyonrails.org/routing.html
+
 end

test/models/customer_test.rb

@@ -3,7 +3,27 @@
 describe Customer do
   let(:customer) { Customer.new }
 
-  it "must be valid" do
-    value(customer).must_be :valid?
-  end
+  describe "validations" do
+    it "can be created if all fields are provided" do
+      start_count = Customer.count
+      c = Customer.new(name: "Tamira", registered_at: "Date registered", address: "An address", city: "Seattle", state: "WA", postal_code: "zip", phone: "111111111", account_credit: 15.50)
+
+      c.must_be :valid?
+
+      c.save
+      Customer.count.must_equal start_count + 1
+    end # can be created
+
+    it "can't be created without a title" do
+      start_count = Customer.count
+      c = Customer.new(registered_at: "Date registered", address: "An address", city: "Seattle", state: "WA", postal_code: "zip", phone: "111111111", account_credit: 15.50)
+
+      c.wont_be :valid?
+
+      # can't be saved because it isn't valid 
+      c.save
+      Customer.count.must_equal start_count
+
+    end
+  end # validations
 end

test/models/rental_test.rb

@@ -1,9 +1,5 @@
 require "test_helper"
 
 describe Rental do
-  let(:rental) { Rental.new }
 
-  it "must be valid" do
-    value(rental).must_be :valid?
-  end
 end