Better test name in the java interop koan

* more_jruby:
  [5553333] Updated java interop on to_java method.
  Added cruise task
  java coercion

.gitignore

@@ -1,3 +1,4 @@
 dist
 .project_env.rc
 .path_progress
+*.rbc

Rakefile

@@ -15,6 +15,7 @@ today    = Time.now.strftime("%Y-%m-%d")
 TAR_FILE = "#{DIST_DIR}/rubykoans-#{today}.tgz"
 ZIP_FILE = "#{DIST_DIR}/rubykoans-#{today}.zip"
 
+CLEAN.include("**/*.rbc")
 CLOBBER.include(DIST_DIR)
 
 module Koans
@@ -57,6 +58,27 @@ module Koans
   end
 end
 
+module RubyImpls
+  # Calculate the list of relevant Ruby implementations.
+  def self.find_ruby_impls
+    rubys = `rvm list`.gsub(/=>/,'').split(/\n/).sort
+    expected.map { |impl|
+      last = rubys.grep(Regexp.new(Regexp.quote(impl))).last
+      last ? last.split.first : nil
+    }.compact
+  end
+
+  # Return a (cached) list of relevant Ruby implementations.
+  def self.list
+    @list ||= find_ruby_impls
+  end
+
+  # List of expected ruby implementations.
+  def self.expected
+    %w(ruby-1.8.6 ruby-1.8.7 ruby-1.9.2 jruby ree)
+  end
+end
+
 task :default => :walk_the_path
 
 task :walk_the_path do
@@ -107,3 +129,38 @@ SRC_FILES.each do |koan_src|
     Koans.make_koan_file koan_src, t.name
   end
 end
+
+task :run do
+  puts 'koans'
+  Dir.chdir("src") do
+    puts "in #{Dir.pwd}"
+    sh "ruby path_to_enlightenment.rb"
+  end
+end
+
+
+desc "Pre-checkin tests (=> run_all)"
+task :cruise => :run_all
+
+desc "Run the completed koans againts a list of relevant Ruby Implementations"
+task :run_all do
+  results = []
+  RubyImpls.list.each do |impl|
+    puts "=" * 40
+    puts "On Ruby #{impl}"
+    sh "rvm #{impl} rake run"
+    results << [impl, "RAN"]
+    puts
+  end
+  puts "=" * 40
+  puts "Summary:"
+  puts
+  results.each do |impl, res|
+    puts "#{impl} => RAN"
+  end
+  puts
+  RubyImpls.expected.each do |requested_impl|
+    impl_pattern = Regexp.new(Regexp.quote(requested_impl))
+    puts "No Results for #{requested_impl}" unless results.detect { |x| x.first =~ impl_pattern }
+  end
+end

koans/about_array_assignment.rb

@@ -18,13 +18,19 @@ class AboutArrayAssignment < EdgeCase::Koan
     assert_equal __, last_name
   end
 
-  def test_parallel_assignments_with_extra_variables
+  def test_parallel_assignments_with_splat_operator
+    first_name, *last_name = ["John", "Smith", "III"]
+    assert_equal __, first_name
+    assert_equal __, last_name
+  end
+
+  def test_parallel_assignments_with_too_few_variables
     first_name, last_name = ["Cher"]
     assert_equal __, first_name
     assert_equal __, last_name
   end
 
-  def test_parallel_assignements_with_subarrays
+  def test_parallel_assignments_with_subarrays
     first_name, last_name = [["Willie", "Rae"], "Johnson"]
     assert_equal __, first_name
     assert_equal __, last_name

koans/about_arrays.rb

@@ -45,9 +45,9 @@ class AboutArrays < EdgeCase::Koan
   end
 
   def test_arrays_and_ranges
-    assert_equal Range, (1..5).class
+    assert_equal __, (1..5).class
     assert_not_equal [1,2,3,4,5], (1..5)
-    assert_equal [1,2,3,4,5], (1..5).to_a
+    assert_equal __, (1..5).to_a
     assert_equal __, (1...5).to_a
   end
 

koans/about_classes.rb

@@ -130,7 +130,7 @@ class AboutClasses < EdgeCase::Koan
     fido = Dog6.new("Fido")
     rover = Dog6.new("Rover")
 
-    assert_not_equal rover.name, fido.name
+    assert_equal __, rover.name != fido.name
   end
 
   # ------------------------------------------------------------------
@@ -164,12 +164,12 @@ class AboutClasses < EdgeCase::Koan
 
   def test_to_s_provides_a_string_version_of_the_object
     fido = Dog7.new("Fido")
-    assert_equal "Fido", fido.to_s
+    assert_equal __, fido.to_s
   end
 
   def test_to_s_is_used_in_string_interpolation
     fido = Dog7.new("Fido")
-    assert_equal "My dog is Fido", "My dog is #{fido}"
+    assert_equal __, "My dog is #{fido}"
   end
 
   def test_inspect_provides_a_more_complete_string_version

koans/about_dice_project.rb

@@ -1,11 +1,10 @@
 require File.expand_path(File.dirname(__FILE__) + '/edgecase')
 
-class DiceSet
-  attr_reader :values
-  def roll(n)
-    @values = (1..n).map { rand(6) + 1 }
-  end
-end
+# Implement a DiceSet Class here:
+#
+# class DiceSet
+#   code ...
+# end
 
 class AboutDiceProject < EdgeCase::Koan
   def test_can_create_a_dice_set

koans/about_exceptions.rb

@@ -22,8 +22,8 @@ class AboutExceptions < EdgeCase::Koan
 
     assert_equal __, result
 
-    assert ex.is_a?(StandardError), "Failure message."
-    assert ex.is_a?(RuntimeError), "Failure message."
+    assert_equal __, ex.is_a?(StandardError), "Should be a Standard Error"
+    assert_equal __, ex.is_a?(RuntimeError),  "Should be a Runtime Error"
 
     assert RuntimeError.ancestors.include?(StandardError),
       "RuntimeError is a subclass of StandardError"

koans/about_hashes.rb

@@ -3,7 +3,7 @@ require File.expand_path(File.dirname(__FILE__) + '/edgecase')
 class AboutHashes < EdgeCase::Koan
   def test_creating_hashes
     empty_hash = Hash.new
-    assert_equal Hash, empty_hash.class
+    assert_equal __, empty_hash.class
     assert_equal({}, empty_hash)
     assert_equal __, empty_hash.size
   end
@@ -25,7 +25,7 @@ class AboutHashes < EdgeCase::Koan
     hash[:one] = "eins"
 
     expected = { :one => __, :two => "dos" }
-    assert_equal expected, hash
+    assert_equal __, expected == hash
 
     # Bonus Question: Why was "expected" broken out into a variable
     # rather than used as a literal?
@@ -35,7 +35,7 @@ class AboutHashes < EdgeCase::Koan
     hash1 = { :one => "uno", :two => "dos" }
     hash2 = { :two => "dos", :one => "uno" }
 
-    assert_equal hash1, hash2
+    assert_equal __, hash1 == hash2
   end
 
   def test_hash_keys
@@ -43,7 +43,7 @@ class AboutHashes < EdgeCase::Koan
     assert_equal __, hash.keys.size
     assert_equal __, hash.keys.include?(:one)
     assert_equal __, hash.keys.include?(:two)
-    assert_equal Array, hash.keys.class
+    assert_equal __, hash.keys.class
   end
 
   def test_hash_values
@@ -51,16 +51,16 @@ class AboutHashes < EdgeCase::Koan
     assert_equal __, hash.values.size
     assert_equal __, hash.values.include?("uno")
     assert_equal __, hash.values.include?("dos")
-    assert_equal Array, hash.values.class
+    assert_equal __, hash.values.class
   end
 
   def test_combining_hashes
     hash = { "jim" => 53, "amy" => 20, "dan" => 23 }
     new_hash = hash.merge({ "jim" => 54, "jenny" => 26 })
 
-    assert_not_equal hash, new_hash
+    assert_equal __, hash != new_hash
 
     expected = { "jim" => __, "amy" => 20, "dan" => 23, "jenny" => __ }
-    assert_equal expected, new_hash
+    assert_equal __, expected == new_hash
   end
 end

koans/about_iteration.rb

@@ -12,7 +12,7 @@ class AboutIteration < EdgeCase::Koan
     array.each do |item|
       sum += item
     end
-    assert_equal 6, sum
+    assert_equal __, sum
   end
 
   def test_each_can_use_curly_brace_blocks_too

koans/about_java_interop.rb

@@ -0,0 +1,137 @@
+require File.expand_path(File.dirname(__FILE__) + '/edgecase')
+
+include Java
+
+# Concepts
+# * Pull in a java class
+# * calling a method, Camel vs snake
+# * Resovling module/class name conflicts
+# * Showing what gets returned
+# * Ruby Strings  VS Java Strings
+# * Calling custom java class
+# * Calling Ruby from java???
+
+class AboutJavaInterop < EdgeCase::Koan
+  def test_using_a_java_library_class
+    java_array = java.util.ArrayList.new
+    assert_equal __, java_array.class
+  end
+
+  def test_java_class_can_be_referenced_using_both_ruby_and_java_like_syntax
+    assert_equal __, Java::JavaUtil::ArrayList == java.util.ArrayList
+  end
+
+  def test_include_class_includes_class_in_module_scope
+    assert_nil defined?(TreeSet)
+    include_class "java.util.TreeSet"
+    assert_equal __, defined?(TreeSet)
+  end
+
+  # THINK ABOUT IT:
+  #
+  # What if we use:
+  #
+  #   include_class "java.lang.String"
+  #
+  # What would be the value of the String constant after this
+  # include_class is run?  Would it be useful to provide a way of
+  # aliasing java classes to different names?
+
+  JString = java.lang.String
+  def test_also_java_class_can_be_given_ruby_aliases
+    java_string = JString.new("A Java String")
+    assert_equal __, java_string.class
+    assert_equal __, JString
+  end
+
+  def test_can_directly_call_java_methods_on_java_objects
+    java_string = JString.new("A Java String")
+    assert_equal __, java_string.toLowerCase
+  end
+
+  def test_jruby_provides_snake_case_versions_of_java_methods
+    java_string = JString.new("A Java String")
+    assert_equal __, java_string.to_lower_case
+  end
+
+  def test_jruby_provides_question_mark_versions_of_boolean_methods
+    java_string = JString.new("A Java String")
+    assert_equal __, java_string.endsWith("String")
+    assert_equal __, java_string.ends_with("String")
+    assert_equal __, java_string.ends_with?("String")
+  end
+
+  def test_java_string_are_not_ruby_strings
+    ruby_string = "A Java String"
+    java_string = java.lang.String.new(ruby_string)
+    assert_equal __, java_string.is_a?(java.lang.String)
+    assert_equal __, java_string.is_a?(String)
+  end
+
+  def test_java_strings_can_be_compared_to_ruby_strings_maybe
+    ruby_string = "A Java String"
+    java_string = java.lang.String.new(ruby_string)
+    assert_equal __, ruby_string == java_string
+    assert_equal __, java_string == ruby_string
+
+    # THINK ABOUT IT:
+    #
+    # Is there any possible way for this to be more wrong?
+    #
+    # SERIOUSLY, THINK ABOUT IT:
+    #
+    # Why do you suppose that Ruby and Java strings compare like that?
+    #
+    # ADVANCED THINK ABOUT IT:
+    #
+    # Is there a way to make Ruby/Java string comparisons commutative?
+    # How would you do it?
+  end
+
+  def test_however_most_methods_returning_strings_return_ruby_strings
+    java_array = java.util.ArrayList.new
+    assert_equal __, java_array.toString
+    assert_equal __, java_array.toString.is_a?(String)
+    assert_equal __, java_array.toString.is_a?(java.lang.String)
+  end
+
+  def test_some_ruby_objects_can_be_coerced_to_java
+    assert_equal __, "ruby string".to_java.class
+    assert_equal __, 1.to_java.class
+    assert_equal __, 9.32.to_java.class
+    assert_equal __, false.to_java.class
+  end
+
+  def test_some_ruby_objects_are_not_coerced_to_what_you_might_expect
+    assert_equal __, [].to_java.class == Java::JavaUtil::ArrayList
+    assert_equal __, {}.to_java.class == Java::JavaUtil::HashMap
+    assert_equal __, Object.new.to_java.class == Java::JavaLang::Object
+  end
+
+  def test_java_collections_are_enumerable
+    java_array = java.util.ArrayList.new
+    java_array << "one" << "two" << "three"
+    assert_equal __, java_array.map { |item| item.upcase }
+  end
+
+  # ------------------------------------------------------------------
+
+  # Open the Java ArrayList class and add a new method.
+  class Java::JavaUtil::ArrayList
+    def multiply_all
+      result = 1
+      each do |item|
+        result *= item
+      end
+      result
+    end
+  end
+
+  def test_java_class_are_open_from_ruby
+    java_array = java.util.ArrayList.new
+    java_array.add_all([1,2,3,4,5])
+
+    assert_equal __, java_array.multiply_all
+  end
+
+end

koans/about_methods.rb

@@ -36,12 +36,12 @@ class AboutMethods < EdgeCase::Koan
     exception = assert_raise(___) do
       my_global_method
     end
-    assert_match(/#{__ of arguments")}/, exception.message)
+    assert_match(/__/, exception.message)
 
     exception = assert_raise(___) do
       my_global_method(1,2,3)
     end
-    assert_match(/#{__ of arguments")}/, exception.message)
+    assert_match(/__/, exception.message)
   end
 
   # ------------------------------------------------------------------

koans/about_regular_expressions.rb

@@ -3,11 +3,11 @@ require File.expand_path(File.dirname(__FILE__) + '/edgecase')
 
 class AboutRegularExpressions < EdgeCase::Koan
   def test_a_pattern_is_a_regular_expression
-    assert_equal Regexp, /pattern/.class
+    assert_equal __, /pattern/.class
   end
 
   def test_a_regexp_can_search_a_string_for_matching_content
-    assert_equal "match", "some matching content"[/match/]
+    assert_equal __, "some matching content"[/match/]
   end
 
   def test_a_failed_match_returns_nil

koans/about_scope.rb

@@ -29,8 +29,8 @@ class AboutScope < EdgeCase::Koan
     assert_equal __, fido.identify
     assert_equal __, rover.identify
 
-    assert_not_equal fido.class, rover.class
-    assert_not_equal Jims::Dog, Joes::Dog
+    assert_equal __, fido.class != rover.class
+    assert_equal __, Jims::Dog != Joes::Dog
   end
 
   # ------------------------------------------------------------------

koans/about_symbols.rb

@@ -11,8 +11,8 @@ class AboutSymbols < EdgeCase::Koan
     symbol2 = :a_symbol
     symbol3 = :something_else
 
-    assert symbol1 == __
-    assert symbol1 != __
+    assert_equal __, symbol1 == symbol2
+    assert_equal __, symbol1 == symbol3
   end
 
   def test_identical_symbols_are_a_single_internal_object
@@ -24,14 +24,14 @@ class AboutSymbols < EdgeCase::Koan
   end
 
   def test_method_names_become_symbols
-    all_symbols = Symbol.all_symbols
-    assert_equal __, all_symbols.include?(:test_method_names_become_symbols)
+    symbols_as_strings = Symbol.all_symbols.map { |x| x.to_s }
+    assert_equal __, symbols_as_strings.include?("test_method_names_become_symbols")
   end
 
   # THINK ABOUT IT:
   #
-  # Why do we capture the list of symbols before we check for the
-  # method name?
+  # Why do we convert the list of symbols to strings and then compare
+  # against the string value rather than against symbols?
 
   in_ruby_version("mri") do
     RubyConstant = "What is the sound of one hand clapping?"
@@ -53,7 +53,7 @@ class AboutSymbols < EdgeCase::Koan
     assert_equal symbol, __.to_sym
   end
 
-  def test_symbols_with_spaces_can_be_built
+  def test_symbols_with_interpolation_can_be_built
     value = "and"
     symbol = :"cats #{value} dogs"
 

koans/about_to_str.rb

@@ -0,0 +1,54 @@
+require File.expand_path(File.dirname(__FILE__) + '/edgecase')
+
+class AboutToStr < EdgeCase::Koan
+
+  class CanNotBeTreatedAsString
+    def to_s
+      "non-string-like"
+    end
+  end
+
+  def test_to_s_returns_a_string_representation
+    not_like_a_string = CanNotBeTreatedAsString.new
+    assert_equal __, not_like_a_string.to_s
+  end
+
+  def test_normally_objects_cannot_be_used_where_strings_are_expected
+    assert_raise(___) do
+      File.exist?(CanNotBeTreatedAsString.new)
+    end
+  end
+
+  # ------------------------------------------------------------------
+
+  class CanBeTreatedAsString
+    def to_s
+      "string-like"
+    end
+
+    def to_str
+      to_s
+    end
+  end
+
+  def test_to_str_also_returns_a_string_representation
+    like_a_string = CanBeTreatedAsString.new
+    assert_equal __, like_a_string.to_str
+  end
+
+  def test_to_str_allows_objects_to_be_treated_as_strings
+    assert_equal __, File.exist?(CanBeTreatedAsString.new)
+  end
+
+  # ------------------------------------------------------------------
+
+  def acts_like_a_string?(string)
+    string = string.to_str if string.respond_to?(:to_str)
+    string.is_a?(String)
+  end
+
+  def test_user_defined_code_can_check_for_to_str
+    assert_equal __, acts_like_a_string?(CanNotBeTreatedAsString.new)
+    assert_equal __,  acts_like_a_string?(CanBeTreatedAsString.new)
+  end
+end

koans/edgecase.rb

@@ -3,6 +3,10 @@
 
 require 'test/unit/assertions'
 
+# --------------------------------------------------------------------
+# Support code for the Ruby Koans.
+# --------------------------------------------------------------------
+
 class FillMeInError < StandardError
 end
 
@@ -16,6 +20,8 @@ def in_ruby_version(*versions)
   yield if versions.any? { |v| ruby_version?(v) }
 end
 
+# Standard, generic replacement value.
+# If value19 is given, it is used inplace of value for Ruby 1.9.
 def __(value="FILL ME IN", value19=:mu)
   if RUBY_VERSION < "1.9"
     value
@@ -24,6 +30,7 @@ def __(value="FILL ME IN", value19=:mu)
   end
 end
 
+# Numeric replacement value.
 def _n_(value=999999, value19=:mu)
   if RUBY_VERSION < "1.9"
     value
@@ -32,10 +39,12 @@ def _n_(value=999999, value19=:mu)
   end
 end
 
+# Error object replacement value.
 def ___(value=FillMeInError)
   value
 end
 
+# Method name replacement.
 class Object
   def ____(method=nil)
     if method
@@ -48,7 +57,25 @@ class Object
   end
 end
 
+class String
+  def side_padding(width)
+    extra = width - self.size
+    if width < 0
+      self
+    else
+      left_padding = extra / 2
+      right_padding = (extra+1)/2
+      (" " * left_padding) + self + (" " *right_padding)
+    end
+  end
+end
+
 module EdgeCase
+  class << self
+    def simple_output
+      ENV['SIMPLE_KOAN_OUTPUT'] == 'true'
+    end
+  end
 
   module Color
     #shamelessly stolen (and modified) from redgreen
@@ -66,16 +93,29 @@ module EdgeCase
     end
 
     def colorize(string, color_value)
-      if ENV['NO_COLOR']
-        string
-      else
+      if use_colors?
         color(color_value) + string + color(COLORS[:clear])
+      else
+        string
       end
     end
 
     def color(color_value)
       "\e[#{color_value}m"
     end
+
+    def use_colors?
+      return false if ENV['NO_COLOR']
+      if ENV['ANSI_COLOR'].nil?
+        ! using_windows?
+      else
+        ENV['ANSI_COLOR'] =~ /^(t|y)/i
+      end
+    end
+
+    def using_windows?
+      File::ALT_SEPARATOR
+    end
   end
 
   class Sensei
@@ -176,6 +216,21 @@ module EdgeCase
     end
 
     def end_screen
+      if EdgeCase.simple_output
+        boring_end_screen
+      else
+        artistic_end_screen
+      end
+    end
+
+    def boring_end_screen
+      puts "Mountains are again merely mountains"
+    end
+
+    def artistic_end_screen
+      "JRuby 1.9.x Koans"
+      ruby_version = "(in #{'J' if defined?(JRUBY_VERSION)}Ruby #{defined?(JRUBY_VERSION) ? JRUBY_VERSION : RUBY_VERSION})"
+      ruby_version = ruby_version.side_padding(54)
         completed = <<-ENDTEXT
                                   ,,   ,  ,,
                                 :      ::::,    :::,
@@ -192,8 +247,8 @@ module EdgeCase
  ,:::::::::::,                                                    ::::::::::::,
  :::::::::::,                                                     ,::::::::::::
 :::::::::::::                                                     ,::::::::::::
-::::::::::::                       Ruby Koans                      ::::::::::::,
-::::::::::::                                                      ,::::::::::::,
+::::::::::::                      Ruby Koans                       ::::::::::::,
+::::::::::::#{                  ruby_version                     },::::::::::::,
 :::::::::::,                                                      , ::::::::::::
 ,:::::::::::::,                brought to you by                 ,,::::::::::::,
 ::::::::::::::                                                    ,::::::::::::
@@ -260,7 +315,7 @@ ENDTEXT
 
     def find_interesting_lines(backtrace)
       backtrace.reject { |line|
-        line =~ /test\/unit\/|edgecase\.rb/
+        line =~ /test\/unit\/|edgecase\.rb|minitest/
       }
     end
 

koans/path_to_enlightenment.rb

@@ -31,4 +31,8 @@ require 'about_scope'
 require 'about_class_methods'
 require 'about_message_passing'
 require 'about_proxy_object_project'
+require 'about_to_str'
+in_ruby_version("jruby") do
+  require 'about_java_interop'
+end
 require 'about_extra_credit'

rakelib/checks.rake

@@ -15,6 +15,7 @@ namespace "check" do
     puts
   end
 
+  desc "Check that asserts have __ replacements"
   task :asserts do
     puts "Checking for asserts missing the replacement text:"
     begin
@@ -28,4 +29,5 @@ namespace "check" do
   end
 end
 
+desc "Run some simple consistancy checks"
 task :check => ["check:abouts", "check:asserts"]

src/about_array_assignment.rb

@@ -18,13 +18,19 @@ class AboutArrayAssignment < EdgeCase::Koan
     assert_equal __("Smith"), last_name
   end
 
-  def test_parallel_assignments_with_extra_variables
+  def test_parallel_assignments_with_splat_operator
+    first_name, *last_name = ["John", "Smith", "III"]
+    assert_equal __("John"), first_name
+    assert_equal __(["Smith","III"]), last_name
+  end
+
+  def test_parallel_assignments_with_too_few_variables
     first_name, last_name = ["Cher"]
     assert_equal __("Cher"), first_name
     assert_equal __(nil), last_name
   end
 
-  def test_parallel_assignements_with_subarrays
+  def test_parallel_assignments_with_subarrays
     first_name, last_name = [["Willie", "Rae"], "Johnson"]
     assert_equal __(["Willie", "Rae"]), first_name
     assert_equal __("Johnson"), last_name

src/about_dice_project.rb

@@ -1,5 +1,12 @@
 require File.expand_path(File.dirname(__FILE__) + '/edgecase')
 
+# Implement a DiceSet Class here:
+#
+# class DiceSet
+#   code ...
+# end
+
+#--
 class DiceSet
   attr_reader :values
   def roll(n)
@@ -7,6 +14,7 @@ class DiceSet
   end
 end
 
+#++
 class AboutDiceProject < EdgeCase::Koan
   def test_can_create_a_dice_set
     dice = DiceSet.new

src/about_exceptions.rb

@@ -22,8 +22,8 @@ class AboutExceptions < EdgeCase::Koan
 
     assert_equal __(:exception_handled), result
 
-    assert ex.is_a?(___(StandardError)), "Failure message."
-    assert ex.is_a?(___(RuntimeError)), "Failure message."
+    assert_equal __(true), ex.is_a?(StandardError), "Should be a Standard Error"
+    assert_equal __(true), ex.is_a?(RuntimeError),  "Should be a Runtime Error"
 
     assert RuntimeError.ancestors.include?(StandardError), # __
       "RuntimeError is a subclass of StandardError"

src/about_java_interop.rb

@@ -95,4 +95,43 @@ class AboutJavaInterop < EdgeCase::Koan
     assert_equal __(false), java_array.toString.is_a?(java.lang.String)
   end
 
+  def test_some_ruby_objects_can_be_coerced_to_java
+    assert_equal __(Java::JavaLang::String), "ruby string".to_java.class
+    assert_equal __(Java::JavaLang::Long), 1.to_java.class
+    assert_equal __(Java::JavaLang::Double), 9.32.to_java.class
+    assert_equal __(Java::JavaLang::Boolean), false.to_java.class
+  end
+
+  def test_some_ruby_objects_are_not_coerced_to_what_you_might_expect
+    assert_equal __(false), [].to_java.class == Java::JavaUtil::ArrayList
+    assert_equal __(false), {}.to_java.class == Java::JavaUtil::HashMap
+    assert_equal __(false), Object.new.to_java.class == Java::JavaLang::Object
+  end
+
+  def test_java_collections_are_enumerable
+    java_array = java.util.ArrayList.new
+    java_array << "one" << "two" << "three"
+    assert_equal __(["ONE", "TWO", "THREE"]), java_array.map { |item| item.upcase }
+  end
+
+  # ------------------------------------------------------------------
+
+  # Open the Java ArrayList class and add a new method.
+  class Java::JavaUtil::ArrayList
+    def multiply_all
+      result = 1
+      each do |item|
+        result *= item
+      end
+      result
+    end
+  end
+
+  def test_java_class_are_open_from_ruby
+    java_array = java.util.ArrayList.new
+    java_array.add_all([1,2,3,4,5])
+
+    assert_equal __(120), java_array.multiply_all
+  end
+
 end

src/about_methods.rb

@@ -43,12 +43,15 @@ class AboutMethods < EdgeCase::Koan
     exception = assert_raise(___(ArgumentError)) do
       my_global_method
     end
-    assert_match(/#{__("wrong (number|#) of arguments")}/, exception.message)
+    #--
+    pattern = "wrong (number|#) of arguments"
+    #++
+    assert_match(/#{__(pattern)}/, exception.message)
 
     exception = assert_raise(___(ArgumentError)) do
       my_global_method(1,2,3)
     end
-    assert_match(/#{__("wrong (number|#) of arguments")}/, exception.message)
+    assert_match(/#{__(pattern)}/, exception.message)
   end
 
   # ------------------------------------------------------------------

src/about_symbols.rb

@@ -11,8 +11,8 @@ class AboutSymbols < EdgeCase::Koan
     symbol2 = :a_symbol
     symbol3 = :something_else
 
-    assert symbol1 == __(symbol2)
-    assert symbol1 != __(symbol3)
+    assert_equal __(true), symbol1 == symbol2
+    assert_equal __(false), symbol1 == symbol3
   end
 
   def test_identical_symbols_are_a_single_internal_object
@@ -24,14 +24,14 @@ class AboutSymbols < EdgeCase::Koan
   end
 
   def test_method_names_become_symbols
-    all_symbols = Symbol.all_symbols
-    assert_equal __(true), all_symbols.include?(:test_method_names_become_symbols)
+    symbols_as_strings = Symbol.all_symbols.map { |x| x.to_s }
+    assert_equal __(true), symbols_as_strings.include?("test_method_names_become_symbols")
   end
 
   # THINK ABOUT IT:
   #
-  # Why do we capture the list of symbols before we check for the
-  # method name?
+  # Why do we convert the list of symbols to strings and then compare
+  # against the string value rather than against symbols?
 
   in_ruby_version("mri") do
     RubyConstant = "What is the sound of one hand clapping?"
@@ -53,7 +53,7 @@ class AboutSymbols < EdgeCase::Koan
     assert_equal symbol, __("cats and dogs").to_sym
   end
 
-  def test_symbols_with_spaces_can_be_built
+  def test_symbols_with_interpolation_can_be_built
     value = "and"
     symbol = :"cats #{value} dogs"
 

src/about_to_str.rb

@@ -0,0 +1,54 @@
+require File.expand_path(File.dirname(__FILE__) + '/edgecase')
+
+class AboutToStr < EdgeCase::Koan
+
+  class CanNotBeTreatedAsString
+    def to_s
+      "non-string-like"
+    end
+  end
+
+  def test_to_s_returns_a_string_representation
+    not_like_a_string = CanNotBeTreatedAsString.new
+    assert_equal __("non-string-like"), not_like_a_string.to_s
+  end
+
+  def test_normally_objects_cannot_be_used_where_strings_are_expected
+    assert_raise(___(TypeError)) do
+      File.exist?(CanNotBeTreatedAsString.new)
+    end
+  end
+
+  # ------------------------------------------------------------------
+
+  class CanBeTreatedAsString
+    def to_s
+      "string-like"
+    end
+
+    def to_str
+      to_s
+    end
+  end
+
+  def test_to_str_also_returns_a_string_representation
+    like_a_string = CanBeTreatedAsString.new
+    assert_equal __("string-like"), like_a_string.to_str
+  end
+
+  def test_to_str_allows_objects_to_be_treated_as_strings
+    assert_equal __(false), File.exist?(CanBeTreatedAsString.new)
+  end
+
+  # ------------------------------------------------------------------
+
+  def acts_like_a_string?(string)
+    string = string.to_str if string.respond_to?(:to_str)
+    string.is_a?(String)
+  end
+
+  def test_user_defined_code_can_check_for_to_str
+    assert_equal __(false), acts_like_a_string?(CanNotBeTreatedAsString.new)
+    assert_equal __(true),  acts_like_a_string?(CanBeTreatedAsString.new)
+  end
+end

src/edgecase.rb

@@ -93,16 +93,29 @@ module EdgeCase
     end
 
     def colorize(string, color_value)
-      if ENV['NO_COLOR']
-        string
-      else
+      if use_colors?
         color(color_value) + string + color(COLORS[:clear])
+      else
+        string
       end
     end
 
     def color(color_value)
       "\e[#{color_value}m"
     end
+
+    def use_colors?
+      return false if ENV['NO_COLOR']
+      if ENV['ANSI_COLOR'].nil?
+        ! using_windows?
+      else
+        ENV['ANSI_COLOR'] =~ /^(t|y)/i
+      end
+    end
+
+    def using_windows?
+      File::ALT_SEPARATOR
+    end
   end
 
   class Sensei

src/path_to_enlightenment.rb

@@ -31,4 +31,8 @@ require 'about_scope'
 require 'about_class_methods'
 require 'about_message_passing'
 require 'about_proxy_object_project'
+require 'about_to_str'
+in_ruby_version("jruby") do
+  require 'about_java_interop'
+end
 require 'about_extra_credit'