diff --git a/.gitignore b/.gitignore
index d87d4be..9938105 100644
--- a/.gitignore
+++ b/.gitignore
@@ -15,3 +15,5 @@ spec/reports
 test/tmp
 test/version_tmp
 tmp
+.idea
+gemfiles/*.lock
diff --git a/.rspec b/.rspec
new file mode 100644
index 0000000..83e16f8
--- /dev/null
+++ b/.rspec
@@ -0,0 +1,2 @@
+--color
+--require spec_helper
diff --git a/.travis.yml b/.travis.yml
index 65ea71b..2705718 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -1,5 +1,15 @@
 language: ruby
-rvm: 
-  - 2.1.0
+rvm:
   - 2.0.0
-  - 1.9.3
\ No newline at end of file
+  - 2.1
+  - ruby-head
+  - jruby-19mode # JRuby in 1.9 mode
+  - rbx-2
+gemfile:
+  - gemfiles/activemodel_4.0.gemfile
+  - gemfiles/activemodel_4.1.gemfile
+  - gemfiles/activemodel_4.2.gemfile
+matrix:
+  allow_failures:
+    - rvm: ruby-head
+bundler_args: --without local_development
diff --git a/Appraisals b/Appraisals
new file mode 100644
index 0000000..289da58
--- /dev/null
+++ b/Appraisals
@@ -0,0 +1,11 @@
+appraise "activemodel-4.0" do
+  gem "activemodel", "~> 4.0.0"
+end
+
+appraise "activemodel-4.1" do
+  gem "activemodel", "~> 4.1.0"
+end
+
+appraise "activemodel-4.2" do
+  gem "activemodel", "~> 4.2.0.beta4"
+end
diff --git a/Gemfile b/Gemfile
index d161c9d..f264083 100644
--- a/Gemfile
+++ b/Gemfile
@@ -2,3 +2,20 @@ source 'https://rubygems.org'
 
 # Specify your gem's dependencies in bank.gemspec
 gemspec
+
+
+group :test do
+  gem 'simplecov', '>= 0.9.0', :require => false
+  gem 'coveralls', :require => false
+end
+
+group :local_development do
+  gem 'terminal-notifier-guard', require: false if RUBY_PLATFORM.downcase.include?('darwin')
+  gem 'guard-rspec', '>= 4.3.1' ,require: false
+  gem 'guard-bundler', require: false
+  gem 'guard-preek', require: false
+  gem 'guard-rubocop', require: false
+  gem 'guard-reek', github: 'pericles/guard-reek', require: false
+  gem 'pry'
+  gem 'appraisal'
+end
\ No newline at end of file
diff --git a/Rakefile b/Rakefile
index 35eb6c0..4c774a2 100644
--- a/Rakefile
+++ b/Rakefile
@@ -1,19 +1,6 @@
 require 'bundler/gem_tasks'
-require 'rake/testtask'
+require 'rspec/core/rake_task'
 
-Rake::TestTask.new do |t|
-  t.pattern = 'spec/**/*_spec.rb'
-  t.libs << 'spec'
-end
+RSpec::Core::RakeTask.new(:spec)
 
-desc 'Run tests'
-task :default => :test
-
-desc 'Run console'
-task :console do
-  require 'irb'
-  require 'irb/completion'
-  require 'bank/contact'
-  ARGV.clear
-  IRB.start
-end
+task default: :spec
diff --git a/bank.gemspec b/bank.gemspec
index 7fb9ba6..ed33423 100644
--- a/bank.gemspec
+++ b/bank.gemspec
@@ -18,8 +18,7 @@ Gem::Specification.new do |spec|
   spec.test_files    = spec.files.grep(%r{^(test|spec|features)/})
   spec.require_paths = ['lib']
 
-  spec.add_development_dependency 'bundler', '~> 1.5'
+  spec.add_development_dependency 'bundler'
   spec.add_development_dependency 'rake'
-  spec.add_development_dependency 'minitest', '~> 4.2'
-  spec.add_development_dependency 'activemodel', '~> 4.0.0'
+  spec.add_development_dependency 'activemodel', '>= 4', '< 5'
 end
diff --git a/gemfiles/activemodel_4.0.gemfile b/gemfiles/activemodel_4.0.gemfile
new file mode 100644
index 0000000..8c59b68
--- /dev/null
+++ b/gemfiles/activemodel_4.0.gemfile
@@ -0,0 +1,23 @@
+# This file was generated by Appraisal
+
+source "https://rubygems.org"
+
+gem "activemodel", "~> 4.0.0"
+
+group :test do
+  gem "simplecov", ">= 0.9.0", :require => false
+  gem "coveralls", :require => false
+end
+
+group :local_development do
+  gem "terminal-notifier-guard", :require => false
+  gem "guard-rspec", ">= 4.3.1", :require => false
+  gem "guard-bundler", :require => false
+  gem "guard-preek", :require => false
+  gem "guard-rubocop", :require => false
+  gem "guard-reek", :github => "pericles/guard-reek", :require => false
+  gem "pry"
+  gem "appraisal"
+end
+
+gemspec :path => "../"
diff --git a/gemfiles/activemodel_4.1.gemfile b/gemfiles/activemodel_4.1.gemfile
new file mode 100644
index 0000000..fb5a45f
--- /dev/null
+++ b/gemfiles/activemodel_4.1.gemfile
@@ -0,0 +1,23 @@
+# This file was generated by Appraisal
+
+source "https://rubygems.org"
+
+gem "activemodel", "~> 4.1.0"
+
+group :test do
+  gem "simplecov", ">= 0.9.0", :require => false
+  gem "coveralls", :require => false
+end
+
+group :local_development do
+  gem "terminal-notifier-guard", :require => false
+  gem "guard-rspec", ">= 4.3.1", :require => false
+  gem "guard-bundler", :require => false
+  gem "guard-preek", :require => false
+  gem "guard-rubocop", :require => false
+  gem "guard-reek", :github => "pericles/guard-reek", :require => false
+  gem "pry"
+  gem "appraisal"
+end
+
+gemspec :path => "../"
diff --git a/gemfiles/activemodel_4.2.gemfile b/gemfiles/activemodel_4.2.gemfile
new file mode 100644
index 0000000..b6da054
--- /dev/null
+++ b/gemfiles/activemodel_4.2.gemfile
@@ -0,0 +1,23 @@
+# This file was generated by Appraisal
+
+source "https://rubygems.org"
+
+gem "activemodel", "~> 4.2.0.beta4"
+
+group :test do
+  gem "simplecov", ">= 0.9.0", :require => false
+  gem "coveralls", :require => false
+end
+
+group :local_development do
+  gem "terminal-notifier-guard", :require => false
+  gem "guard-rspec", ">= 4.3.1", :require => false
+  gem "guard-bundler", :require => false
+  gem "guard-preek", :require => false
+  gem "guard-rubocop", :require => false
+  gem "guard-reek", :github => "pericles/guard-reek", :require => false
+  gem "pry"
+  gem "appraisal"
+end
+
+gemspec :path => "../"
diff --git a/spec/activemodel_spec.rb b/spec/activemodel_spec.rb
index b3aae4b..53e3631 100644
--- a/spec/activemodel_spec.rb
+++ b/spec/activemodel_spec.rb
@@ -22,30 +22,28 @@ def persisted?
   end
 end
 
-describe IbanValidator do
-  before {
-    @model = Company.new
-  }
+RSpec.describe IbanValidator do
+  let(:model) { ::Company.new }
 
   it 'should be valid' do
-    @model.iban = 'FR1420041010050500013M02606'
-    @model.valid?.must_equal true
+    model.iban = 'FR1420041010050500013M02606'
+    expect(model.valid?).to be_truthy
   end
 
   it 'should not be valid' do
-    @model.iban = 'FR1420041010050500013'
-    @model.valid?.must_equal false
-    @model.errors[:iban].must_include 'is invalid'
+    model.iban = 'FR1420041010050500013'
+    expect(model.valid?).to be_falsey
+    expect(model.errors[:iban]).to include 'is invalid'
   end
 
   it 'should not validate with nil value' do
-    @model.iban.must_equal nil
-    @model.valid?.must_equal false
+    expect(model.iban).to be_nil
+    expect(model.valid?).to be_falsey
   end
 
   it 'should not use the validator with option allow_nil: true' do
-    @person = Person.new
-    @person.iban.must_equal nil
-    @person.valid?.must_equal true
+    person = Person.new
+    expect(person.iban).to be_nil
+    expect(person.valid?).to be_truthy
   end
 end
diff --git a/spec/bic_spec.rb b/spec/bic_spec.rb
index f357c31..9ac74e6 100644
--- a/spec/bic_spec.rb
+++ b/spec/bic_spec.rb
@@ -1,52 +1,46 @@
 require 'spec_helper'
 
-describe Bank::BIC do
-  before do
-    @bic = Bank::BIC.new('ABNACHZ8XXX')
-  end
+RSpec.describe Bank::BIC do
+  let(:bic) { ::Bank::BIC.new('ABNACHZ8XXX') }
 
   it 'returns the right bank code' do
-    @bic.bank_code.must_equal 'ABNA'
+    expect(bic.bank_code).to eq 'ABNA'
   end
 
   it 'returns the right country code' do
-    @bic.country_code.must_equal 'CH'
+    expect(bic.country_code).to eq 'CH'
   end
 
   it 'returns the right location code' do
-    @bic.location_code.must_equal 'Z8'
+    expect(bic.location_code).to eq 'Z8'
   end
 
   it 'returns the right branch code' do
-    @bic.branch_code.must_equal 'XXX'
+    expect(bic.branch_code).to eq 'XXX'
   end
 
   [8, 11].each do |len|
-    describe 'x' * len do
+    context 'x' * len do
       it 'has a valid length' do
-        Bank::BIC.new('x' * len).valid_length?.must_equal true
+        expect(::Bank::BIC.new('x' * len).valid_length?).to be_truthy
       end
     end
   end
 
   1.upto(20) do |len|
     if len != 8 && len != 11
-      describe 'x' * len do
+      context 'x' * len do
         it 'has a valid length' do
-          Bank::BIC.new('x' * len).valid_length?.must_equal false
+          expect(::Bank::BIC.new('x' * len).valid_length?).to be_falsey
         end
       end
     end
   end
 
-  [
-    'UCJAES2MXXX',
-    'ABAGATWWXXX',
-    'UCJAES2MXXX'
-  ].each do |code|
-    describe code do
+  %w(UCJAES2MXXX ABAGATWWXXX UCJAES2MXXX).each do |code|
+    context code do
       it 'has a valid format' do
-        Bank::BIC.new(code).valid_format?.must_equal true
+        expect(::Bank::BIC.new(code).valid_format?).to be_truthy
       end
     end
   end
@@ -54,9 +48,9 @@
   [
     '12341234'
   ].each do |code|
-    describe code do
+    context code do
       it 'has an invalid format' do
-        Bank::BIC.new(code).valid_format?.must_equal false
+        expect(::Bank::BIC.new(code).valid_format?).to be_falsey
       end
     end
   end
diff --git a/spec/contact_spec.rb b/spec/contact_spec.rb
index 7837f23..8c1a293 100644
--- a/spec/contact_spec.rb
+++ b/spec/contact_spec.rb
@@ -2,29 +2,28 @@
 
 require 'bank/contact'
 
-describe Bank::Contact do
-  before do
-    @iban = Bank::IBAN.new('FR14 2004 1010 0505 0001 3M026 06')
-    @bic  = Bank::BIC.new('BYLADEM1203')
-    @contact = Bank::Contact.new(@iban, @bic)
-  end
+RSpec.describe Bank::Contact do
+  let(:iban) { Bank::IBAN.new('FR14 2004 1010 0505 0001 3M026 06') }
+  let(:bic) { Bank::BIC.new('BYLADEM1203') }
+  let(:contact) { Bank::Contact.new(iban, bic) }
 
   it 'should validate' do
-    @contact.valid?.must_equal true
+    expect(contact.valid?).to be_truthy
   end
 
   it 'should have the right types' do
-    @contact.iban.must_be_kind_of Bank::IBAN
-    @contact.bic.must_be_kind_of Bank::BIC
+    expect(contact.iban).to be_a Bank::IBAN
+    expect(contact.bic).to be_a Bank::BIC
   end
 
   it 'should export to_h' do
-    @contact.to_h.must_equal(
-      iban: 'FR1420041010050500013M02606',
-      bic: 'BYLADEM1203')
+    expect(contact.to_h).to eq({
+                                 iban: 'FR1420041010050500013M02606',
+                                 bic:  'BYLADEM1203'
+                               })
   end
 
   it 'should export to_a' do
-    @contact.to_a.must_equal(['FR1420041010050500013M02606', 'BYLADEM1203'])
+    expect(contact.to_a).to eq(['FR1420041010050500013M02606', 'BYLADEM1203'])
   end
 end
diff --git a/spec/iban_spec.rb b/spec/iban_spec.rb
index 6b83736..17ac118 100644
--- a/spec/iban_spec.rb
+++ b/spec/iban_spec.rb
@@ -1,58 +1,56 @@
 require 'spec_helper'
 
-describe Bank::IBAN do
-  before do
-    @iban = Bank::IBAN.new('FR14 2004 1010 0505 0001 3M026 06')
-  end
+RSpec.describe Bank::IBAN do
+  let(:iban) { Bank::IBAN.new('FR14 2004 1010 0505 0001 3M026 06') }
 
   it 'should valid from class method' do
-    Bank::IBAN.valid?('FR14 2004 1010 0505 0001 3M026 06').must_equal true
+    expect(Bank::IBAN.valid?('FR14 2004 1010 0505 0001 3M026 06')).to be_truthy
   end
 
   it 'should load the validation rules' do
-    Bank.load_specifications(:iban).wont_be :empty?
-    Bank.load_specifications(:iban).must_be_kind_of Hash
+    expect(Bank.load_specifications(:iban)).to_not be_empty
+    expect(Bank.load_specifications(:iban)).to be_a Hash
   end
 
   it 'should return the county code' do
-    @iban.country_code.must_equal 'FR'
+    expect(iban.country_code).to eq 'FR'
   end
 
   it 'should return the check digits' do
-    @iban.check_digits.must_equal '14'
+    expect(iban.check_digits).to eq '14'
   end
 
   it 'should return the BBAN' do
-    @iban.bban.must_be_kind_of Bank::BBAN
-    @iban.bban.to_s.must_equal '20041010050500013M02606'
+    expect(iban.bban).to be_a Bank::BBAN
+    expect(iban.bban.to_s).to eq '20041010050500013M02606'
   end
 
   it 'should convert to integer value' do
-    @iban.to_i.must_equal 200410100505000132202606152714
+    expect(iban.to_i).to eq 200410100505000132202606152714
   end
 
   it 'should convert to string' do
-    @iban.to_s.must_equal 'FR1420041010050500013M02606'
+    expect(iban.to_s).to eq 'FR1420041010050500013M02606'
   end
 
   it 'should convert to formatted string' do
-    @iban.to_s(true).must_equal 'FR14 2004 1010 0505 0001 3M02 606'
+    expect(iban.to_s(true)).to eq 'FR14 2004 1010 0505 0001 3M02 606'
   end
 
   it 'should respond_to? account_number' do
-    @iban.respond_to?(:account_number).must_equal true
+    expect(iban.respond_to?(:account_number)).to be_truthy
   end
 
   it 'should return account_number' do
-    @iban.account_number.must_equal '0500013M026'
+    expect(iban.account_number).to eq '0500013M026'
   end
 
   it 'should return bank_identifier' do
-    @iban.bank_identifier.must_equal '20041'
+    expect(iban.bank_identifier).to eq '20041'
   end
 
   it 'should return branch_identifier' do
-    @iban.branch_identifier.must_equal '01005'
+    expect(iban.branch_identifier).to eq '01005'
   end
 
   [
@@ -140,9 +138,9 @@
     'TR330006100519786457841326',
     'AE260211000000230064016'
   ].each do |code|
-    describe code do
+    context code do
       it 'should be valid' do
-        Bank::IBAN.new(code).valid?.must_equal true
+        expect(Bank::IBAN.new(code).valid?).to be_truthy
       end
     end
   end
diff --git a/spec/spec_helper.rb b/spec/spec_helper.rb
index ae892d9..0b8c6e1 100644
--- a/spec/spec_helper.rb
+++ b/spec/spec_helper.rb
@@ -1,11 +1,14 @@
-# -*- encoding: utf-8 -*-
-require 'rubygems'
-require 'bundler/setup'
-
-require 'minitest/autorun'
-require 'minitest/spec'
-begin; require 'turn/autorun'; rescue LoadError; end
+require 'simplecov'
+require 'coveralls'
 
+SimpleCov.formatter = SimpleCov::Formatter::MultiFormatter[
+  SimpleCov::Formatter::HTMLFormatter,
+  Coveralls::SimpleCov::Formatter
+]
+SimpleCov.start do
+  add_filter 'spec'
+  minimum_coverage(76)
+end
 require 'active_model'
 require 'bank/iban'
-require 'bank/bic'
+require 'bank/bic'
\ No newline at end of file