Tests

app/models/account.rb

@@ -3,6 +3,8 @@ class Account < ActiveRecord::Base
   belongs_to :registrar
   has_many :account_activities
 
+  validates :account_type, presence: true
+
   CASH = 'cash'
 
   def activities

spec/models/account_spec.rb

@@ -0,0 +1,51 @@
+require 'rails_helper'
+
+describe Account do
+  it { should belong_to(:registrar) }
+  it { should have_many(:account_activities) }
+
+  context 'with invalid attribute' do
+    before :all do
+      @account = Account.new
+    end
+
+    it 'should not be valid' do
+      @account.valid?
+      @account.errors.full_messages.should match_array(["Account type is missing"])
+    end
+
+    it 'should not have any versions' do
+      @account.versions.should == []
+    end
+  end
+
+  context 'with valid attributes' do
+    before :all do
+      @account = Fabricate(:account)
+    end
+
+    it 'should be valid' do
+      @account.valid?
+      @account.errors.full_messages.should match_array([])
+      s = 0.0
+      @account.activities.map { |x| s += x.sum }
+      @account.balance.should == s
+    end
+
+    it 'should be valid twice' do
+      @account = Fabricate(:account)
+      @account.valid?
+      @account.errors.full_messages.should match_array([])
+    end
+
+    it 'should have one version' do
+      with_versioning do
+        @account.versions.should == []
+        @account.account_type = 'new_type'
+        @account.save
+        @account.errors.full_messages.should match_array([])
+        @account.versions.size.should == 1
+      end
+    end
+  end
+end