5 files changed, 64 insertions, 3 deletions
diff --git a/activerecord/test/cases/adapters/mysql2/mysql2_adapter_test.rb b/activerecord/test/cases/adapters/mysql2/mysql2_adapter_test.rb
new file mode 100644
index 0000000000..4efd728754
--- /dev/null
+++ b/activerecord/test/cases/adapters/mysql2/mysql2_adapter_test.rb
@@ -0,0 +1,44 @@
+require "cases/helper"
+
+class Mysql2AdapterTest < ActiveRecord::Mysql2TestCase
+  def setup
+    @conn = ActiveRecord::Base.connection
+  end
+
+  def test_columns_for_distinct_zero_orders
+    assert_equal "posts.id",
+      @conn.columns_for_distinct("posts.id", [])
+  end
+
+  def test_columns_for_distinct_one_order
+    assert_equal "posts.id, posts.created_at AS alias_0",
+      @conn.columns_for_distinct("posts.id", ["posts.created_at desc"])
+  end
+
+  def test_columns_for_distinct_few_orders
+    assert_equal "posts.id, posts.created_at AS alias_0, posts.position AS alias_1",
+      @conn.columns_for_distinct("posts.id", ["posts.created_at desc", "posts.position asc"])
+  end
+
+  def test_columns_for_distinct_with_case
+    assert_equal(
+      'posts.id, CASE WHEN author.is_active THEN UPPER(author.name) ELSE UPPER(author.email) END AS alias_0',
+      @conn.columns_for_distinct('posts.id',
+        ["CASE WHEN author.is_active THEN UPPER(author.name) ELSE UPPER(author.email) END"])
+    )
+  end
+
+  def test_columns_for_distinct_blank_not_nil_orders
+    assert_equal "posts.id, posts.created_at AS alias_0",
+      @conn.columns_for_distinct("posts.id", ["posts.created_at desc", "", "   "])
+  end
+
+  def test_columns_for_distinct_with_arel_order
+    order = Object.new
+    def order.to_sql
+      "posts.created_at desc"
+    end
+    assert_equal "posts.id, posts.created_at AS alias_0",
+      @conn.columns_for_distinct("posts.id", [order])
+  end
+end
diff --git a/activerecord/test/cases/adapters/mysql2/sp_test.rb b/activerecord/test/cases/adapters/mysql2/sp_test.rb
index cdaa2cca44..4197ba45f1 100644
--- a/activerecord/test/cases/adapters/mysql2/sp_test.rb
+++ b/activerecord/test/cases/adapters/mysql2/sp_test.rb
@@ -22,6 +22,12 @@ class Mysql2StoredProcedureTest < ActiveRecord::Mysql2TestCase
     assert @connection.active?, "Bad connection use by 'Mysql2Adapter.select_rows'"
   end
 
+  def test_multi_results_from_select_one
+    row = @connection.select_one('CALL topics(1);')
+    assert_equal 'David', row['author_name']
+    assert @connection.active?, "Bad connection use by 'Mysql2Adapter.select_one'"
+  end
+
   def test_multi_results_from_find_by_sql
     topics = Topic.find_by_sql 'CALL topics(3);'
     assert_equal 3, topics.size
diff --git a/activerecord/test/cases/finder_test.rb b/activerecord/test/cases/finder_test.rb
index 9f90ab79a1..75a74c052d 100644
--- a/activerecord/test/cases/finder_test.rb
+++ b/activerecord/test/cases/finder_test.rb
@@ -19,7 +19,7 @@ require 'models/car'
 require 'models/tyre'
 
 class FinderTest < ActiveRecord::TestCase
-  fixtures :companies, :topics, :entrants, :developers, :developers_projects, :posts, :comments, :accounts, :authors, :customers, :categories, :categorizations, :cars
+  fixtures :companies, :topics, :entrants, :developers, :developers_projects, :posts, :comments, :accounts, :authors, :author_addresses, :customers, :categories, :categorizations, :cars
 
   def test_find_by_id_with_hash
     assert_raises(ActiveRecord::StatementInvalid) do
@@ -993,10 +993,13 @@ class FinderTest < ActiveRecord::TestCase
   end
 
   def test_find_with_order_on_included_associations_with_construct_finder_sql_for_association_limiting_and_is_distinct
-    assert_equal 2, Post.includes(authors: :author_address).order('author_addresses.id DESC ').limit(2).to_a.size
+    assert_equal 2, Post.includes(authors: :author_address).
+      where.not(author_addresses: { id: nil }).
+      order('author_addresses.id DESC').limit(2).to_a.size
 
     assert_equal 3, Post.includes(author: :author_address, authors: :author_address).
-                              order('author_addresses_authors.id DESC ').limit(3).to_a.size
+      where.not(author_addresses_authors: { id: nil }).
+      order('author_addresses_authors.id DESC').limit(3).to_a.size
   end
 
   def test_find_with_nil_inside_set_passed_for_one_attribute
diff --git a/activerecord/test/fixtures/author_addresses.yml b/activerecord/test/fixtures/author_addresses.yml
index 7b90572187..cf75e5998d 100644
--- a/activerecord/test/fixtures/author_addresses.yml
+++ b/activerecord/test/fixtures/author_addresses.yml
@@ -3,3 +3,9 @@ david_address:
 
 david_address_extra:
   id: 2
+
+mary_address:
+  id: 3
+
+bob_address:
+  id: 4
diff --git a/activerecord/test/fixtures/authors.yml b/activerecord/test/fixtures/authors.yml
index 832236a486..41c124179e 100644
--- a/activerecord/test/fixtures/authors.yml
+++ b/activerecord/test/fixtures/authors.yml
@@ -9,7 +9,9 @@ david:
 mary:
   id: 2
   name: Mary
+  author_address_id: 3
 
 bob:
   id: 3
   name: Bob
+  author_address_id: 4