#1177: split the rounded total between the greeting lines, so they add up

lib/fbe/award.rb

@@ -396,19 +396,24 @@ def points
     #   bill.line(25, "for documentation")
     #   bill.greeting #=> "You've earned +75 points for this: +50 for code review; +25 for documentation. "
     def greeting
-      items = @lines.map { |l| "#{format('%+d', whole(l[:v]))} #{l[:t]}" }
-      case items.size
-      when 0
-        "You've earned nothing. "
-      when 1
-        "You've earned #{format('%+d', points)} points. "
-      else
-        "You've earned #{format('%+d', points)} points for this: #{items.join('; ')}. "
-      end
+      return "You've earned nothing. " if @lines.empty?
+      items = shares.filter_map { |l| "#{format('%+d', l[:v])} #{l[:t]}" unless l[:v].zero? }
+      return "You've earned #{format('%+d', points)} points. " if @lines.size == 1 || items.empty?
+      "You've earned #{format('%+d', points)} points for this: #{items.join('; ')}. "
     end
 
     private
 
+    # Splits the rounded total between the lines, by the largest remainder.
+    #
+    # @return [Array<Hash>] Lines with whole values that add up to +points+
+    def shares
+      parts = @lines.map { |l| { v: Float(l[:v]).floor, t: l[:t], r: Float(l[:v]) - Float(l[:v]).floor } }
+      extra = points - parts.sum { |l| l[:v] }
+      parts.sort_by.with_index { |l, i| [-l[:r], i] }.first(extra).each { |l| l[:v] += 1 }
+      parts
+    end
+
     # Rounds one line value the way the total is rounded.
     #
     # @param [Float, Integer] value The value of one line

test/fbe/test_award.rb

@@ -81,6 +81,17 @@ def test_some_terms
     end
   end
 
+  def test_greeting_lines_add_up_to_the_total
+    {
+      '(award (give 0.4 "a") (give 0.4 "b") (give 0.4 "c"))' => "You've earned +1 points for this: +1 a. ",
+      '(award (give 0.5 "a") (give 0.5 "b"))' => "You've earned +1 points for this: +1 a. ",
+      '(award (give -3.5 "a") (give 1 "b"))' => "You've earned -3 points for this: -4 a; +1 b. ",
+      '(award (give 0.2 "a") (give 0.2 "b"))' => "You've earned +0 points. "
+    }.each do |q, v|
+      assert_equal(v, Fbe::Award.new(q).bill.greeting, q)
+    end
+  end
+
   def test_some_greetings
     {
       '(award (give (times 7 0.25 "fun")))' => 'You\'ve earned +2 points. ',