Add `create_join_table` migration helper to create HABTM join tables

3 files changed, 82 insertions, 1 deletions

diff --git a/activerecord/test/cases/migration/change_schema_test.rb b/activerecord/test/cases/migration/change_schema_test.rb
index a1ade59e52..f0b1f74bd3 100644
--- a/activerecord/test/cases/migration/change_schema_test.rb
+++ b/activerecord/test/cases/migration/change_schema_test.rb
@@ -173,7 +173,6 @@ module ActiveRecord
           skip "not supported on #{connection.class}"
         end
 
-
         connection.create_table :testings do |t|
           t.column :foo, :string
         end
diff --git a/activerecord/test/cases/migration/command_recorder_test.rb b/activerecord/test/cases/migration/command_recorder_test.rb
index 8f136bce2b..7d026961be 100644
--- a/activerecord/test/cases/migration/command_recorder_test.rb
+++ b/activerecord/test/cases/migration/command_recorder_test.rb
@@ -73,6 +73,18 @@ module ActiveRecord
         assert_equal [:drop_table, [:people_reminders]], drop_table
       end
 
+      def test_invert_create_join_table
+        @recorder.record :create_join_table, [:musics, :artists]
+        drop_table = @recorder.inverse.first
+        assert_equal [:drop_table, [:artists_musics]], drop_table
+      end
+
+      def test_invert_create_join_table_with_table_name
+        @recorder.record :create_join_table, [:musics, :artists, {:table_name => :catalog}]
+        drop_table = @recorder.inverse.first
+        assert_equal [:drop_table, [:catalog]], drop_table
+      end
+
       def test_invert_rename_table
         @recorder.record :rename_table, [:old, :new]
         rename = @recorder.inverse.first
diff --git a/activerecord/test/cases/migration/create_join_table_test.rb b/activerecord/test/cases/migration/create_join_table_test.rb
new file mode 100644
index 0000000000..0428d9ba76
--- /dev/null
+++ b/activerecord/test/cases/migration/create_join_table_test.rb
@@ -0,0 +1,70 @@
+require 'cases/helper'
+
+module ActiveRecord
+  class Migration
+    class CreateJoinTableTest < ActiveRecord::TestCase
+      attr_reader :connection
+
+      def setup
+        super
+        @connection = ActiveRecord::Base.connection
+      end
+
+      def test_create_join_table
+        connection.create_join_table :artists, :musics
+
+        assert_equal %w(artist_id music_id), connection.columns(:artists_musics).map(&:name).sort
+      ensure
+        connection.drop_table :artists_musics
+      end
+
+      def test_create_join_table_set_not_null_by_default
+        connection.create_join_table :artists, :musics
+
+        assert_equal [false, false], connection.columns(:artists_musics).map(&:null)
+      ensure
+        connection.drop_table :artists_musics
+      end
+
+      def test_create_join_table_with_strings
+        connection.create_join_table 'artists', 'musics'
+
+        assert_equal %w(artist_id music_id), connection.columns(:artists_musics).map(&:name).sort
+      ensure
+        connection.drop_table :artists_musics
+      end
+
+      def test_create_join_table_with_the_proper_order
+        connection.create_join_table :videos, :musics
+
+        assert_equal %w(music_id video_id), connection.columns(:musics_videos).map(&:name).sort
+      ensure
+        connection.drop_table :musics_videos
+      end
+
+      def test_create_join_table_with_the_table_name
+        connection.create_join_table :artists, :musics, :table_name => :catalog
+
+        assert_equal %w(artist_id music_id), connection.columns(:catalog).map(&:name).sort
+      ensure
+        connection.drop_table :catalog
+      end
+
+      def test_create_join_table_with_the_table_name_as_string
+        connection.create_join_table :artists, :musics, :table_name => 'catalog'
+
+        assert_equal %w(artist_id music_id), connection.columns(:catalog).map(&:name).sort
+      ensure
+        connection.drop_table :catalog
+      end
+
+      def test_create_join_table_with_column_options
+        connection.create_join_table :artists, :musics, :column_options => {:null => true}
+
+        assert_equal [true, true], connection.columns(:artists_musics).map(&:null)
+      ensure
+        connection.drop_table :artists_musics
+      end
+    end
+  end
+end