change: Regenerate Tests

exercises/change/.meta/generator/change_case.rb

@@ -2,6 +2,25 @@
 
 class ChangeCase < Generator::ExerciseCase
   def workload
-    assert_equal(expected, "Change.generate(#{coins}, #{target})")
+    if error_expected?
+      handle_errors
+    else
+      assert_equal(expected, subject_of_test)
+    end
+  end
+
+  private
+
+  def handle_errors
+    case test_name
+    when 'test_cannot_find_negative_change_values'
+      assert_raises('Change::NegativeTargetError', subject_of_test)
+    else
+      assert_raises('Change::ImpossibleCombinationError', subject_of_test)
+    end
+  end
+
+  def subject_of_test
+    "Change.generate(#{coins}, #{target})"
   end
 end

exercises/change/.meta/solutions/change.rb

@@ -1,18 +1,23 @@
 class Change
   attr_reader :coins, :target
 
+  class NegativeTargetError < ArgumentError; end
+  class ImpossibleCombinationError < StandardError; end
+
   def initialize(coins, target)
     @coins  = coins.sort.reverse
     @target = target
     @total_change = []
   end
 
   def generate
+    raise NegativeTargetError if target < 0
     return [] if target.zero?
 
     calculate_change(coins, [], target)
+    raise ImpossibleCombinationError if total_change.none?
 
-    total_change.any? ? total_change.sort : -1
+    total_change.sort
   end
 
   def self.generate(coins, target)

exercises/change/change_test.rb

@@ -1,7 +1,7 @@
 require 'minitest/autorun'
 require_relative 'change'
 
-# Common test data version: 1.2.0 044d09a
+# Common test data version: 1.3.0 258c807
 class ChangeTest < Minitest::Test
   def test_single_coin_change
     # skip
@@ -45,16 +45,22 @@ def test_no_coins_make_0_change
 
   def test_error_testing_for_change_smaller_than_the_smallest_of_coins
     skip
-    assert_equal -1, Change.generate([5, 10], 3)
+    assert_raises(Change::ImpossibleCombinationError) do
+      Change.generate([5, 10], 3)
+    end
   end
 
   def test_error_if_no_combination_can_add_up_to_target
     skip
-    assert_equal -1, Change.generate([5, 10], 94)
+    assert_raises(Change::ImpossibleCombinationError) do
+      Change.generate([5, 10], 94)
+    end
   end
 
   def test_cannot_find_negative_change_values
     skip
-    assert_equal -1, Change.generate([1, 2, 5], -5)
+    assert_raises(Change::NegativeTargetError) do
+      Change.generate([1, 2, 5], -5)
+    end
   end
 end