Restore identity, add hint messages

re: #10
Changes per discussion at PR: #170

largest-series-product/example.rb

@@ -9,7 +9,9 @@ def initialize(numeric_string)
   def largest_product(length)
     @length = length
     validate_length
-    analyzer
+    return 1 if @digits.empty?
+    collection_of_digits
+    select_max { reduce_to_product  { validate  { separate } } }
   end
 
   private
@@ -19,11 +21,6 @@ def validate_length
       fail(ArgumentError.new 'Not enough digits')
   end
 
-  def analyzer
-    collection_of_digits
-    select_max { reduce_to_product { validate { separate } } }
-  end
-
   def validate
     yield.take_while { |array| array.size == @length }
   end

largest-series-product/largest_series_product_test.rb

@@ -5,6 +5,7 @@
 
 # Rubocop directives
 # rubocop:disable Lint/ParenthesesAsGroupedExpression
+# rubocop:disable Style/AlignParameters:
 #
 class Seriestest < Minitest::Test
   def test_largest_product_of_a_tiny_number
@@ -21,13 +22,15 @@ def test_another_tiny_number
   def test_largest_product_of_2
     skip
     series = Series.new('0123456789')
-    assert_equal 72, series.largest_product(2)
+    assert_equal 72, series.largest_product(2),
+      'Largest product of all sets of 2 result from 8 and 9'
   end
 
   def test_largest_product_of_2_shuffled
     skip
     series = Series.new('576802143')
-    assert_equal 48, series.largest_product(2)
+    assert_equal 48, series.largest_product(2),
+      'Largest product of all sets of 2 result from 6 and 8'
   end
 
   def test_largest_product_of_3
@@ -62,6 +65,13 @@ def test_some_other_big_number
     assert_equal 28_350, series.largest_product(6)
   end
 
+  def test_identity
+    skip
+    series = Series.new('')
+    assert_equal 1, series.largest_product(0),
+      'Identity of an empty group is 1'
+  end
+
   def test_slices_bigger_than_number
     skip
     series = Series.new('123')