Implement shift perturbation

app/services/tables/shift.rb

@@ -9,7 +9,7 @@ module Tables
 
     def each
       @initial_solution.tables.permutation(2) do |table_a, table_b|
-        table_a.each do |person|
+        table_a.dup.each do |person|
           original_discomfort_a = table_a.reset
           original_discomfort_b = table_b.reset
 

spec/services/tables/shift_spec.rb

@@ -1,5 +1,3 @@
-# Copyright (C) 2024 Manuel Bustillo
-
 require 'rails_helper'
 
 module Tables
@@ -16,17 +14,37 @@ module Tables
       context 'when there are two tables with two people each' do
         let(:initial_solution) do
           Distribution.new(min_per_table: 2, max_per_table: 2).tap do |distribution|
-            distribution.tables << %i[a b].to_table
+            distribution.tables << Set[:a, :b].to_table
-            distribution.tables << %i[c d].to_table
+            distribution.tables << Set[:c, :d].to_table
           end
         end
 
         it 'yields all possible shifts between the tables' do
           expect(shifts).to contain_exactly(
-            [[:b], %i[c d a]],
+            [Set[:b], Set[:c, :d, :a]],
-            [[:a], %i[c d b]],
+            [Set[:a], Set[:c, :d, :b]],
-            [%i[b a d], [:c]],
+            [Set[:b, :a, :d], Set[:c]],
-            [%i[b a c], [:d]]
+            [Set[:b, :a, :c], Set[:d]]
+          )
+        end
+      end
+
+      context 'when there are two tables with three people each' do
+        let(:initial_solution) do
+          Distribution.new(min_per_table: 3, max_per_table: 3).tap do |distribution|
+            distribution.tables << Set[:a, :b, :c].to_table
+            distribution.tables << Set[:d, :e, :f].to_table
+          end
+        end
+
+        it 'yields all possible shifts between the tables' do
+          expect(shifts).to contain_exactly(
+            [Set[:b, :c], Set[:d, :e, :f, :a]],
+            [Set[:c, :a], Set[:d, :e, :f, :b]],
+            [Set[:a, :b], Set[:d, :e, :f, :c]],
+            [Set[:a, :b, :c, :d], Set[:e, :f]],
+            [Set[:a, :b, :c, :e], Set[:d, :f]],
+            [Set[:a, :b, :c, :f], Set[:d, :e]]
           )
         end
       end