diff --git a/.rubocop.yml b/.rubocop.yml
index 44a2b1d..9fbc143 100644
--- a/.rubocop.yml
+++ b/.rubocop.yml
@@ -1,4 +1,10 @@
-Documentation:
+Style/Documentation:
+  Enabled: false
+
+Style/StringLiteralsInInterpolation:
+  Enabled: false
+
+Style/StringLiterals:
   Enabled: false
 
 Style/FileName:
diff --git a/lib/coupon_code.rb b/lib/coupon_code.rb
index 537fd1b..ce4aaba 100644
--- a/lib/coupon_code.rb
+++ b/lib/coupon_code.rb
@@ -1,46 +1,13 @@
-require 'coupon_code/version'
 require 'securerandom'
 require 'digest/sha1'
+require 'coupon_code/version'
+require 'coupon_code/generator'
+require 'coupon_code/configuration'
+require 'coupon_code/validator'
 
 module CouponCode
   SYMBOL = '0123456789ABCDEFGHJKLMNPQRTUVWXY'
   PARTS  = 3
   LENGTH = 4
-
-  def self.generate(options = { parts: PARTS })
-    num_parts = options.delete(:parts)
-    parts = []
-    (1..num_parts).each do |i|
-      part = ''
-      (1...LENGTH).each { part << random_symbol }
-      part << checkdigit_alg_1(part, i)
-      parts << part
-    end
-    parts.join('-')
-  end
-
-  def self.validate(orig, num_parts = PARTS)
-    code = orig.upcase
-    code.gsub!(/[^0-9A-Z]+/, '')
-    parts = code.scan(/[0-9A-Z]{#{LENGTH}}/)
-    return if parts.length != num_parts
-    parts.each_with_index do |part, i|
-      data  = part[0...(LENGTH - 1)]
-      check = part[-1]
-      return if check != checkdigit_alg_1(data, i + 1)
-    end
-    parts.join('-')
-  end
-
-  def self.checkdigit_alg_1(orig, check)
-    orig.split('').each_with_index do |c, _|
-      k = SYMBOL.index(c)
-      check = check * 19 + k
-    end
-    SYMBOL[check % 31]
-  end
-
-  def self.random_symbol
-    SYMBOL[rand(SYMBOL.length)]
-  end
+  SEPARATOR = '-'
 end
diff --git a/lib/coupon_code/configuration.rb b/lib/coupon_code/configuration.rb
new file mode 100644
index 0000000..b447bd6
--- /dev/null
+++ b/lib/coupon_code/configuration.rb
@@ -0,0 +1,28 @@
+module CouponCode
+  class << self
+    attr_accessor :configuration
+  end
+
+  def self.config
+    @config ||= Configuration.new
+  end
+
+  def self.configure
+    yield(config)
+  end
+
+  def self.reset
+    @config = Configuration.new
+  end
+
+  class Configuration
+
+    attr_accessor :separator, :part_length, :num_parts
+
+    def initialize
+      @separator = '-'
+      @part_length = 4
+      @num_parts = 3
+    end
+  end
+end
diff --git a/lib/coupon_code/generator.rb b/lib/coupon_code/generator.rb
new file mode 100644
index 0000000..8fac117
--- /dev/null
+++ b/lib/coupon_code/generator.rb
@@ -0,0 +1,18 @@
+module CouponCode
+  def self.generate(options = { parts: PARTS })
+    num_parts = options.delete(:parts)
+    parts = []
+    (1..num_parts).each do |i|
+      part = ''
+      (1...LENGTH).each { part << random_symbol }
+      part << checkdigit_alg_1(part, i)
+      parts << part
+    end
+    parts.join('-')
+  end
+
+  def self.random_symbol
+    SYMBOL[rand(SYMBOL.length)]
+  end
+  private_class_method :random_symbol
+end
diff --git a/lib/coupon_code/validator.rb b/lib/coupon_code/validator.rb
new file mode 100644
index 0000000..61f2433
--- /dev/null
+++ b/lib/coupon_code/validator.rb
@@ -0,0 +1,23 @@
+module CouponCode
+  def self.validate(orig, num_parts = PARTS)
+    code = orig.upcase
+    code.gsub!(/[^0-9A-Z]+/, '')
+    parts = code.scan(/[0-9A-Z]{#{LENGTH}}/)
+    return if parts.length != num_parts
+    parts.each_with_index do |part, i|
+      data  = part[0...(LENGTH - 1)]
+      check = part[-1]
+      return if check != checkdigit_alg_1(data, i + 1)
+    end
+    parts.join('-')
+  end
+
+  def self.checkdigit_alg_1(orig, check)
+    orig.split('').each_with_index do |c, _|
+      k = SYMBOL.index(c)
+      check = check * 19 + k
+    end
+    SYMBOL[check % 31]
+  end
+  private_class_method :checkdigit_alg_1
+end
diff --git a/test/configuration_test.rb b/test/configuration_test.rb
new file mode 100644
index 0000000..af251a7
--- /dev/null
+++ b/test/configuration_test.rb
@@ -0,0 +1,9 @@
+require 'test_helper'
+
+describe 'Configuration' do
+  it 'separator' do
+    config = CouponCode::Configuration.new
+    config.separator = '*'
+    config.separator.must_equal('*')
+  end
+end
diff --git a/test/generator_test.rb b/test/generator_test.rb
new file mode 100644
index 0000000..e587946
--- /dev/null
+++ b/test/generator_test.rb
@@ -0,0 +1,34 @@
+require 'test_helper'
+
+describe CouponCode do
+  def generate(*args)
+    CouponCode.generate(*args)
+  end
+
+  it 'should be loaded.' do
+    CouponCode.must_respond_to(:generate)
+  end
+
+  it 'should generate a code' do
+    generate.wont_be_empty
+  end
+
+  it 'should only contain uppercase letters, digits, and dashes.' do
+    generate.must_match(/^[0-9A-Z-]+$/)
+  end
+
+  it 'should look like XXXX-XXXX-XXXX.' do
+    generate.must_match(/^\w{4}-\w{4}-\w{4}$/)
+  end
+
+  it 'should generate different codes.' do
+    code1 = generate
+    code2 = generate
+    code1.wont_equal(code2)
+  end
+
+  it 'should generate an arbitrary number of parts.' do
+    generate(parts: 2).must_match(/^\w{4}-\w{4}$/)
+    generate(parts: 5).must_match(/^\w{4}-\w{4}-\w{4}-\w{4}-\w{4}$/)
+  end
+end
diff --git a/test/validator_test.rb b/test/validator_test.rb
new file mode 100644
index 0000000..db6108d
--- /dev/null
+++ b/test/validator_test.rb
@@ -0,0 +1,63 @@
+require 'test_helper'
+
+describe Validator do
+  it 'should be loaded.' do
+    CouponCode.must_respond_to(:validate)
+  end
+
+  it 'should fail to validate invalid code.' do
+    CouponCode.validate('').must_equal(nil)
+  end
+
+  it 'should accept a valid code.' do
+    CouponCode.validate('1K7Q-CTFM-LMTC').wont_be_nil
+  end
+
+  it 'should reject a short code.' do
+    CouponCode.validate('1K7Q-CTFM').must_be_nil
+  end
+
+  it 'should accept a short code with correct parts.' do
+    CouponCode.validate('1K7Q-CTFM', 2).wont_be_nil
+  end
+
+  it 'should reject a short code with wrong parts.' do
+    CouponCode.validate('CTFM-1K7Q', 2).must_be_nil
+  end
+
+  it 'should fix and validate a lowercase code.' do
+    code = '1k7q-ctfm-lmtc'
+    CouponCode.validate(code.downcase).must_equal(code.upcase)
+  end
+
+  it 'should validate alternative separators.' do
+    code = '1k7q/ctfm/lmtc'
+    CouponCode.validate(code).must_equal('1K7Q-CTFM-LMTC')
+
+    code = '1k7q ctfm lmtc'
+    CouponCode.validate(code).must_equal('1K7Q-CTFM-LMTC')
+
+    code = '1k7qctfmlmtc'
+    CouponCode.validate(code).must_equal('1K7Q-CTFM-LMTC')
+  end
+
+  it 'should valid code-pretest.' do
+    CouponCode.validate('1K7Q', 1).wont_be_nil
+    CouponCode.validate('1K7C', 1).must_be_nil
+
+    CouponCode.validate('1K7Q-CTFM', 2).wont_be_nil
+    CouponCode.validate('1K7Q-CTFW', 2).must_be_nil
+
+    CouponCode.validate('1K7Q-CTFM-LMTC', 3).wont_be_nil
+    CouponCode.validate('1K7Q-CTFM-LMT1', 3).must_be_nil
+
+    CouponCode.validate('7YQH-1FU7-E1HX-0BG9', 4).wont_be_nil
+    CouponCode.validate('7YQH-1FU7-E1HX-0BGP', 4).must_be_nil
+
+    CouponCode.validate('YENH-UPJK-PTE0-20U6-QYME', 5).wont_be_nil
+    CouponCode.validate('YENH-UPJK-PTE0-20U6-QYMT', 5).must_be_nil
+
+    CouponCode.validate('YENH-UPJK-PTE0-20U6-QYME-RBK1', 6).wont_be_nil
+    CouponCode.validate('YENH-UPJK-PTE0-20U6-QYME-RBK2', 6).must_be_nil
+  end
+end