diff --git a/Gemfile b/Gemfile
index c2bc80e179..8bcffa5cdd 100644
--- a/Gemfile
+++ b/Gemfile
@@ -1,4 +1,13 @@
 source 'https://rubygems.org'
 
+ruby '2.2.5'
+
 gem 'minitest'
 gem 'rubocop', '0.36.0'
+gem 'simplecov'
+gem 'rake'
+
+# These are not strictly necessary, but I use them to automatically run the
+# tests whenever I edit a file.
+gem 'guard'
+gem 'guard-shell'
diff --git a/Guardfile b/Guardfile
new file mode 100644
index 0000000000..6b169849d1
--- /dev/null
+++ b/Guardfile
@@ -0,0 +1,39 @@
+# A sample Guardfile
+# More info at https://github.com/guard/guard#readme
+
+## Uncomment and set this to only include directories you want to watch
+# directories %w(app lib config test spec features) \
+#  .select{|d| Dir.exists?(d) ? d : UI.warning("Directory #{d} does not exist")}
+
+## Note: if you are using the `directories` clause above and you are not
+## watching the project directory ('.'), then you will want to move
+## the Guardfile to a watched dir and symlink it back, e.g.
+#
+#  $ mkdir config
+#  $ mv Guardfile config/
+#  $ ln -s config/Guardfile .
+#
+# and, you'll have to watch "config/Guardfile" instead of "Guardfile"
+
+interactor :off
+
+# Add files and commands to this file, like the example:
+#   watch(%r{file/path}) { `command(s)` }
+#
+guard :shell do
+  watch(/(lib|tests\/)(.*)\.rb$/) do |m|
+    file = m[0]
+	puts "File changed: #{file}"
+    test_file = file[/_test\.rb/] ? file : file.sub(/\.rb/, '_test.rb')
+    commands = 
+		"bundle exec rake test",
+		"bundle exec rubocop -D #{file}"
+	generator = 
+		"bin/generate isogram",
+		"git --no-pager diff exercises/isogram/isogram_test.rb"
+ 	command = commands.join(' && ')
+    p command
+    system(command)
+	system(generator.join(' && '))
+  end
+end
diff --git a/Rakefile b/Rakefile
new file mode 100644
index 0000000000..d93b680454
--- /dev/null
+++ b/Rakefile
@@ -0,0 +1,6 @@
+require 'rake'
+require 'rake/testtask'
+
+Rake::TestTask.new do |task|
+  task.pattern = 'tests/*_test.rb'
+end
diff --git a/bin/executable-tests-check b/bin/executable-tests-check
index 490a58a2e2..771f9d0331 100755
--- a/bin/executable-tests-check
+++ b/bin/executable-tests-check
@@ -3,7 +3,7 @@ require 'minitest/autorun'
 
 # Assume that this file lives in #{base}/bin
 base = File.join(__dir__,'..')
-files = Dir.glob("#{base}/**/*test.rb") + Dir.glob("#{base}/bin/*")
+files = Dir.glob("#{base}/exercises/**/*test.rb") + Dir.glob("#{base}/bin/*")
 
 files.each do |file|
   describe file do
diff --git a/exercises/isogram/.version b/exercises/isogram/.version
index d00491fd7e..d8263ee986 100644
--- a/exercises/isogram/.version
+++ b/exercises/isogram/.version
@@ -1 +1 @@
-1
+2
\ No newline at end of file
diff --git a/exercises/isogram/example.rb b/exercises/isogram/example.rb
index e2b9e3d440..fac7fb8862 100644
--- a/exercises/isogram/example.rb
+++ b/exercises/isogram/example.rb
@@ -1,9 +1,9 @@
 module BookKeeping
-  VERSION = 1
+  VERSION = 2
 end
 
 class Isogram
-  def self.is_isogram?(str)
+  def self.isogram?(str)
     letters = str.downcase.gsub(/[[:punct:]]| /, '').chars
     letters == letters.uniq
   end
diff --git a/exercises/isogram/example.tt b/exercises/isogram/example.tt
index acdd7a80d7..9b58e2c8c3 100644
--- a/exercises/isogram/example.tt
+++ b/exercises/isogram/example.tt
@@ -5,16 +5,10 @@ require 'minitest/autorun'
 require_relative 'isogram'
 
 # Common test data version: <%= sha1 %>
-class IsogramTest < Minitest::Test<% test_cases.each do |test_case| %>
-  def <%= test_case.name %>
-    <%= test_case.skip %>
-    string = '<%= test_case.input %>'
-    <%= test_case.assertion %> Isogram.is_isogram?(string)
-  end
+class IsogramTest < Minitest::Test
+<% test_cases.each_with_index do |test_case,index| %>
+<%=  test_case.render(index) %>
+
 <% end %>
-<%= IO.read(XRUBY_LIB + '/bookkeeping.md') %>
-  def test_bookkeeping
-    skip
-    assert_equal <%= version.next %>, BookKeeping::VERSION
-  end
+<%= test_version_bookkeeping.render %>
 end
diff --git a/exercises/isogram/isogram_test.rb b/exercises/isogram/isogram_test.rb
index 238c8bd83a..f366477e11 100755
--- a/exercises/isogram/isogram_test.rb
+++ b/exercises/isogram/isogram_test.rb
@@ -4,66 +4,54 @@
 require 'minitest/autorun'
 require_relative 'isogram'
 
-# Common test data version: c1cb73f
+# Common test data version: 2adfe21
 class IsogramTest < Minitest::Test
-  def test_duplicates
+  def test_empty_string_has_no_duplicates
     # skip
+    string = ''
+    assert Isogram.isogram?(string), '"" is an isogram'
+  end
+
+  def test_isogram_with_only_lower_case_characters
+    skip
     string = 'duplicates'
-    assert Isogram.is_isogram?(string)
+    assert Isogram.isogram?(string), '"duplicates" is an isogram'
   end
 
-  def test_eleven
+  def test_word_with_one_duplicated_character
     skip
     string = 'eleven'
-    refute Isogram.is_isogram?(string)
+    refute Isogram.isogram?(string), '"eleven" is NOT an isogram'
   end
 
-  def test_subdermatoglyphic
+  def test_longest_reported_english_isogram
     skip
     string = 'subdermatoglyphic'
-    assert Isogram.is_isogram?(string)
+    assert Isogram.isogram?(string), '"subdermatoglyphic" is an isogram'
   end
 
-  def test_alphabet
+  def test_word_with_duplicated_character_in_mixed_case
     skip
     string = 'Alphabet'
-    refute Isogram.is_isogram?(string)
+    refute Isogram.isogram?(string), '"Alphabet" is NOT an isogram'
   end
 
-  def test_thumbscrew_japingly
+  def test_hypothetical_isogrammic_word_with_hyphen
     skip
     string = 'thumbscrew-japingly'
-    assert Isogram.is_isogram?(string)
+    assert Isogram.isogram?(string), '"thumbscrew-japingly" is an isogram'
   end
 
-  def test_hjelmqvist_gryb_zock_pfund_wax
+  def test_isogram_with_duplicated_non_letter_character
     skip
     string = 'Hjelmqvist-Gryb-Zock-Pfund-Wax'
-    assert Isogram.is_isogram?(string)
-  end
-
-  def test_heizölrückstoßabdämpfung
-    skip
-    string = 'Heizölrückstoßabdämpfung'
-    assert Isogram.is_isogram?(string)
+    assert Isogram.isogram?(string), '"Hjelmqvist-Gryb-Zock-Pfund-Wax" is an isogram'
   end
 
-  def test_the_quick_brown_fox
-    skip
-    string = 'the quick brown fox'
-    refute Isogram.is_isogram?(string)
-  end
-
-  def test_emily_jung_schwartzkopf
+  def test_made_up_name_that_is_an_isogram
     skip
     string = 'Emily Jung Schwartzkopf'
-    assert Isogram.is_isogram?(string)
-  end
-
-  def test_éléphant
-    skip
-    string = 'éléphant'
-    refute Isogram.is_isogram?(string)
+    assert Isogram.isogram?(string), '"Emily Jung Schwartzkopf" is an isogram'
   end
 
   # Problems in exercism evolve over time, as we find better ways to ask
@@ -85,6 +73,6 @@ def test_éléphant
 
   def test_bookkeeping
     skip
-    assert_equal 1, BookKeeping::VERSION
+    assert_equal 2, BookKeeping::VERSION
   end
 end
diff --git a/lib/exercise_testcase.rb b/lib/exercise_testcase.rb
new file mode 100644
index 0000000000..c35ee47829
--- /dev/null
+++ b/lib/exercise_testcase.rb
@@ -0,0 +1,60 @@
+class ExerciseTestCase
+  attr_reader :canonical_data
+
+  def initialize(canonical_data)
+    @canonical_data = OpenStruct.new(canonical_data)
+  end
+
+  def render(index = -1)
+    @index = index
+    [comment, *full_method].compact.join("\n") + "\n"
+  end
+
+  def full_method
+    indent( [
+      method_definition,
+      *method_body,
+      method_end
+    ], 2)
+  end
+
+  def comment
+    nil
+  end
+
+  def description
+    canonical_data.description || ''
+  end
+
+  def method_definition
+    "def #{test_name}"
+  end
+
+  def method_body
+    indent( [skip, *workload], 2)
+  end
+
+  def method_end
+    "end"
+  end
+
+  def skip
+    @index.zero? ? '# skip' : 'skip'
+  end
+
+  def test_name
+    "test_#{description_as_test_name}"
+  end
+
+  def description_as_test_name
+    description.downcase.tr_s(' -','_')
+  end
+
+  def workload
+    "assert #{@canonical_data.expected.inspect}, Subject.method #{@canonical_data.input.inspect}"
+  end
+
+  def indent(lines, count)
+    lines.compact.map { |line| ' ' * count + line }
+  end
+end
diff --git a/lib/exercise_testcases.rb b/lib/exercise_testcases.rb
new file mode 100644
index 0000000000..9653f89720
--- /dev/null
+++ b/lib/exercise_testcases.rb
@@ -0,0 +1,20 @@
+class ExerciseTestCases
+  attr_reader :cases_key
+  def initialize(json_data)
+    @data = json_data
+    @cases_key = 'cases'
+  end
+
+  def case_classname
+    classname = self.class.to_s.sub(/Cases$/,'Case')
+    Object.const_get(classname)
+  end
+
+  def parsed_json_cases
+    JSON.parse(@data)[cases_key]
+  end
+
+  def to_a
+    parsed_json_cases.map { |test_case| case_classname.new(test_case) }
+  end
+end
diff --git a/lib/generator.rb b/lib/generator.rb
index 48360e56cd..2ad0292f82 100644
--- a/lib/generator.rb
+++ b/lib/generator.rb
@@ -4,6 +4,9 @@
 require 'json'
 require 'ostruct'
 
+require_relative 'exercise_testcases'
+require_relative 'exercise_testcase'
+
 class Generator
   METADATA_REPOSITORY = 'x-common'.freeze
 
@@ -14,7 +17,6 @@ def initialize(name, cases)
   end
 
   def metadata_dir
-    # rubocop:disable Metrics/LineLength
     File.expand_path(File.join('..', '..', '..', METADATA_REPOSITORY, 'exercises', name), __FILE__)
   end
 
@@ -35,7 +37,22 @@ def sha1
   end
 
   def test_cases
-    cases.call(data)
+    cases.new(data).to_a
+  end
+
+  class BookKeeping < ExerciseTestCase
+    def comment
+      IO.read(XRUBY_LIB + '/bookkeeping.md')
+    end
+
+    def workload
+      'assert_equal 2, BookKeeping::VERSION'
+    end
+  end
+
+  def test_version_bookkeeping
+    BookKeeping.new('description' => 'bookkeeping')
+    #    [comment, "\n", bla.full_method].join
   end
 
   def metadata_repository_missing_message
@@ -51,20 +68,21 @@ def metadata_repository_missing_message
   def generate
     check_metadata_repository_exists
     generate_test_file
-    increment_version
-    increment_version_in_example
+    # increment_version
+    # increment_version_in_example
   end
 
   def check_metadata_repository_exists
     unless File.directory?(metadata_dir)
       STDERR.puts metadata_repository_missing_message
-      fail Errno::ENOENT.new(metadata_dir)
+      raise Errno::ENOENT, metadata_dir
     end
   end
 
   def generate_test_file
     File.open(path_to("#{name.gsub(/[ -]/, '_')}_test.rb"), 'w') do |f|
-      f.write ERB.new(File.read(path_to('example.tt'))).result binding
+      template = File.read(path_to('example.tt'))
+      f.write ERB.new(template, nil, '<>').result binding
     end
   end
 
diff --git a/lib/isogram_cases.rb b/lib/isogram_cases.rb
index 4e042ef693..7f08e5dd30 100644
--- a/lib/isogram_cases.rb
+++ b/lib/isogram_cases.rb
@@ -1,24 +1,26 @@
-class IsogramCase < OpenStruct
+require_relative 'exercise_testcases'
+require_relative 'exercise_testcase'
 
-  def name
-    format('test_%s', description)
-  end
+class IsogramCases < ExerciseTestCases
+end
 
-  def description
-    input.downcase.gsub(/[ -]/,'_')
+class IsogramCase < ExerciseTestCase
+  def workload
+    [
+      "string = '#{canonical_data.input}'",
+      "#{assertion} Isogram.isogram?(string), '#{failure_message}'"
+    ]
   end
 
-  def assertion
-    expected ? 'assert' : 'refute'
+  def failure_message
+    "#{canonical_data.input.inspect} #{is_or_isnt} an isogram"
   end
 
-  def skip
-    index.zero? ? '# skip' : 'skip'
+  def is_or_isnt
+    canonical_data.expected ? 'is' : 'is NOT'
   end
-end
 
-IsogramCases = proc do |data|
-  JSON.parse(data)['cases'].map.with_index do |row, i|
-    IsogramCase.new(row.merge('index' => i))
+  def assertion
+    canonical_data.expected ? 'assert' : 'refute'
   end
 end
diff --git a/tests/exercise_testcase_test.rb b/tests/exercise_testcase_test.rb
new file mode 100644
index 0000000000..536075e52e
--- /dev/null
+++ b/tests/exercise_testcase_test.rb
@@ -0,0 +1,42 @@
+require_relative 'test_helper'
+require 'exercise_testcase'
+
+class ExerciseTestCaseTest < Minitest::Test
+  def test_can_be_created
+    subject = ExerciseTestCase.new nil
+    assert subject.instance_of? ExerciseTestCase
+  end
+
+  def test_render
+    subject = ExerciseTestCase.new nil
+    expected = "  def test_\n    skip\n    assert nil, Subject.method nil\n  end\n"
+    assert_equal expected, subject.render
+  end
+
+  def dont_test_can_get_data
+    data = { 'key' => 'value' }
+    expected = OpenStruct.new(data)
+    subject = ExerciseTestCase.new(data)
+    assert_equal expected, subject.canonical_data
+  end
+
+  def dont_test_test_name_from_description
+    data = { 'description' => 'from_description' }
+    subject = ExerciseTestCase.new(data)
+    assert_equal 'test_from_description', subject.test_name
+  end
+
+  def dont_test_test_name_from_description_replaces_spaces
+    data = { 'description' => 'from description with spaces' }
+    subject = ExerciseTestCase.new(data)
+    assert_equal 'test_from_description_with_spaces', subject.test_name
+  end
+
+  def dont_test_test_name_from_description_replaces_hyphens
+    data = { 'description' => 'from-description-with-hyphens' }
+    subject = ExerciseTestCase.new(data)
+    assert_equal 'test_from_description_with_hyphens', subject.test_name
+  end
+
+
+end
diff --git a/tests/exercise_testcases_test.rb b/tests/exercise_testcases_test.rb
new file mode 100644
index 0000000000..f75cbd2f51
--- /dev/null
+++ b/tests/exercise_testcases_test.rb
@@ -0,0 +1,14 @@
+require_relative 'test_helper'
+require 'exercise_testcases'
+require 'exercise_testcase'
+require 'json'
+
+class ExerciseTestCasesTest < Minitest::Test
+  def test_initialistion
+    some_json = JSON.generate(cases: [{ 'description' => 'first' },{ description: 'second' }])
+    subject = ExerciseTestCases.new(some_json)
+    result = subject.to_a
+    assert_equal 2, result.size
+    assert_equal ExerciseTestCase, result.first.class
+  end
+end
diff --git a/tests/isogram_cases_test.rb b/tests/isogram_cases_test.rb
new file mode 100644
index 0000000000..cdb9a1f45f
--- /dev/null
+++ b/tests/isogram_cases_test.rb
@@ -0,0 +1,17 @@
+require_relative 'test_helper'
+require 'isogram_cases'
+
+class IsogramCaseTest < Minitest::Test
+  def test_can_create_a_whole_test
+    data = { description: 'isogram is an isogram', input: 'isogram', expected: true }
+    subject = IsogramCase.new(data)
+    expected = <<EXPECTED.gsub(/^ {4}/,'')
+      def test_isogram_is_an_isogram
+        skip
+        string = 'isogram'
+        assert Isogram.isogram?(string), '\"isogram\" is an isogram'
+      end
+EXPECTED
+    assert_equal expected, subject.render
+  end
+end
diff --git a/tests/test_helper.rb b/tests/test_helper.rb
new file mode 100644
index 0000000000..6c38278221
--- /dev/null
+++ b/tests/test_helper.rb
@@ -0,0 +1,16 @@
+require 'simplecov'
+SimpleCov.start do
+  add_filter "/tests/"
+  add_group "Utilities" do |file|
+    !(file.filename =~ /_cases\.rb$/)
+  end
+  add_group "Cases", "_cases.rb"
+end
+
+require 'minitest/autorun'
+
+
+$LOAD_PATH.push(File.expand_path('../../lib',__FILE__))
+
+# So we can be sure we have coverage on the whole lib directory:
+Dir.glob('lib/*.rb').each {|file| require file.gsub(/(^lib\/|\.rb$)/,'') }