1 files changed, 54 insertions, 0 deletions
diff --git a/activerecord/test/cases/adapters/postgresql/legacy_migration_test.rb b/activerecord/test/cases/adapters/postgresql/legacy_migration_test.rb
new file mode 100644
index 0000000000..082fe95053
--- /dev/null
+++ b/activerecord/test/cases/adapters/postgresql/legacy_migration_test.rb
@@ -0,0 +1,54 @@
+require "cases/helper"
+
+class PostgresqlLegacyMigrationTest < ActiveRecord::PostgreSQLTestCase
+  class GenerateTableWithoutBigserial < ActiveRecord::Migration[5.0]
+    def change
+      create_table :legacy_integer_pk do |table|
+        table.string :foo
+      end
+
+      create_table :override_pk, id: :bigint do |table|
+        table.string :bar
+      end
+    end
+  end
+
+  def setup
+    super
+
+    @migration_verbose_old = ActiveRecord::Migration.verbose
+    ActiveRecord::Migration.verbose = false
+
+    migrations = [GenerateTableWithoutBigserial.new(nil, 1)]
+    ActiveRecord::Migrator.new(:up, migrations).migrate
+  end
+
+  def teardown
+    ActiveRecord::Migration.verbose = @migration_verbose_old
+
+    super
+  end
+
+  def test_create_table_uses_serial_as_pkey_by_default
+    col = column(:legacy_integer_pk, :id)
+    assert_equal "integer", sql_type_for(col)
+    assert col.serial?
+  end
+
+  def test_create_tables_respects_pk_column_type_override
+    col = column(:override_pk, :id)
+    assert_equal "bigint", sql_type_for(col)
+  end
+
+  private
+
+    def column(table_name, column_name)
+      ActiveRecord::Base.connection.
+        columns(table_name.to_s).
+        detect { |c| c.name == column_name.to_s }
+    end
+
+    def sql_type_for(col)
+      col && col.sql_type
+    end
+end