Ensure #second acts like #first AR finder

This commit bring the famous ordinal Array instance methods defined
in ActiveSupport into ActiveRecord as fully-fledged finders.

These finders ensure a default ascending order of the table's primary
key, and utilize the OFFSET SQL verb to locate the user's desired
record. If an offset is defined in the query, calling #second adds
to the offset to get the actual desired record.

Fixes #13743.

1 files changed, 10 insertions, 8 deletions

diff --git a/activerecord/test/cases/calculations_test.rb b/activerecord/test/cases/calculations_test.rb
index 2f6913167d..0bc81ffe56 100644
--- a/activerecord/test/cases/calculations_test.rb
+++ b/activerecord/test/cases/calculations_test.rb
@@ -466,14 +466,14 @@ class CalculationsTest < ActiveRecord::TestCase
   def test_distinct_is_honored_when_used_with_count_operation_after_group
     # Count the number of authors for approved topics
     approved_topics_count = Topic.group(:approved).count(:author_name)[true]
-    assert_equal approved_topics_count, 3
+    assert_equal approved_topics_count, 4
     # Count the number of distinct authors for approved Topics
     distinct_authors_for_approved_count = Topic.group(:approved).distinct.count(:author_name)[true]
-    assert_equal distinct_authors_for_approved_count, 2
+    assert_equal distinct_authors_for_approved_count, 3
   end
 
   def test_pluck
-    assert_equal [1,2,3,4], Topic.order(:id).pluck(:id)
+    assert_equal [1,2,3,4,5], Topic.order(:id).pluck(:id)
   end
 
   def test_pluck_without_column_names
@@ -509,7 +509,7 @@ class CalculationsTest < ActiveRecord::TestCase
   end
 
   def test_pluck_with_qualified_column_name
-    assert_equal [1,2,3,4], Topic.order(:id).pluck("topics.id")
+    assert_equal [1,2,3,4,5], Topic.order(:id).pluck("topics.id")
   end
 
   def test_pluck_auto_table_name_prefix
@@ -557,11 +557,13 @@ class CalculationsTest < ActiveRecord::TestCase
   def test_pluck_multiple_columns
     assert_equal [
       [1, "The First Topic"], [2, "The Second Topic of the day"],
-      [3, "The Third Topic of the day"], [4, "The Fourth Topic of the day"]
+      [3, "The Third Topic of the day"], [4, "The Fourth Topic of the day"],
+      [5, "The Fifth Topic of the day"]
     ], Topic.order(:id).pluck(:id, :title)
     assert_equal [
       [1, "The First Topic", "David"], [2, "The Second Topic of the day", "Mary"],
-      [3, "The Third Topic of the day", "Carl"], [4, "The Fourth Topic of the day", "Carl"]
+      [3, "The Third Topic of the day", "Carl"], [4, "The Fourth Topic of the day", "Carl"],
+      [5, "The Fifth Topic of the day", "Jason"]
     ], Topic.order(:id).pluck(:id, :title, :author_name)
   end
 
@@ -587,7 +589,7 @@ class CalculationsTest < ActiveRecord::TestCase
 
   def test_pluck_replaces_select_clause
     taks_relation = Topic.select(:approved, :id).order(:id)
-    assert_equal [1,2,3,4], taks_relation.pluck(:id)
-    assert_equal [false, true, true, true], taks_relation.pluck(:approved)
+    assert_equal [1,2,3,4,5], taks_relation.pluck(:id)
+    assert_equal [false, true, true, true, true], taks_relation.pluck(:approved)
   end
 end