Correctly dump composite primary key

Example:

    create_table :barcodes, primary_key: ["region", "code"] do |t|
      t.string :region
      t.integer :code
    end

2 files changed, 28 insertions, 1 deletions

diff --git a/activerecord/test/cases/primary_keys_test.rb b/activerecord/test/cases/primary_keys_test.rb
index 0745a37ee9..66c28c4958 100644
--- a/activerecord/test/cases/primary_keys_test.rb
+++ b/activerecord/test/cases/primary_keys_test.rb
@@ -241,6 +241,33 @@ class PrimaryKeyAnyTypeTest < ActiveRecord::TestCase
   end
 end
 
+class CompositePrimaryKeyTest < ActiveRecord::TestCase
+  include SchemaDumpingHelper
+
+  self.use_transactional_tests = false
+
+  def setup
+    @connection = ActiveRecord::Base.connection
+    @connection.create_table(:barcodes, primary_key: ["region", "code"], force: true) do |t|
+      t.string :region
+      t.integer :code
+    end
+  end
+
+  def teardown
+    @connection.drop_table(:barcodes, if_exists: true)
+  end
+
+  def test_composite_primary_key
+    assert_equal ["region", "code"], @connection.primary_keys("barcodes")
+  end
+
+  def test_collectly_dump_composite_primary_key
+    schema = dump_table_schema "barcodes"
+    assert_match %r{create_table "barcodes", primary_key: \["region", "code"\]}, schema
+  end
+end
+
 if current_adapter?(:MysqlAdapter, :Mysql2Adapter)
   class PrimaryKeyWithAnsiQuotesTest < ActiveRecord::TestCase
     self.use_transactional_tests = false
diff --git a/activerecord/test/cases/test_case.rb b/activerecord/test/cases/test_case.rb
index 7761ea5612..f93e85f5e2 100644
--- a/activerecord/test/cases/test_case.rb
+++ b/activerecord/test/cases/test_case.rb
@@ -103,7 +103,7 @@ module ActiveRecord
     # ignored SQL, or better yet, use a different notification for the queries
     # instead examining the SQL content.
     oracle_ignored     = [/^select .*nextval/i, /^SAVEPOINT/, /^ROLLBACK TO/, /^\s*select .* from all_triggers/im, /^\s*select .* from all_constraints/im, /^\s*select .* from all_tab_cols/im]
-    mysql_ignored      = [/^SHOW TABLES/i, /^SHOW FULL FIELDS/, /^SHOW CREATE TABLE /i, /^SHOW VARIABLES /]
+    mysql_ignored      = [/^SHOW TABLES/i, /^SHOW FULL FIELDS/, /^SHOW CREATE TABLE /i, /^SHOW VARIABLES /, /^\s*SELECT column_name\b.*\bFROM information_schema\.key_column_usage\b/im]
     postgresql_ignored = [/^\s*select\b.*\bfrom\b.*pg_namespace\b/im, /^\s*select tablename\b.*from pg_tables\b/im, /^\s*select\b.*\battname\b.*\bfrom\b.*\bpg_attribute\b/im, /^SHOW search_path/i]
     sqlite3_ignored =    [/^\s*SELECT name\b.*\bFROM sqlite_master/im, /^\s*SELECT sql\b.*\bFROM sqlite_master/im]