fix table cleanup (#38)

- correctly remove temporal table
- remove functions, too
- add spec and refactor support

lib/temporal_tables/connection_adapters/postgresql_adapter.rb

@@ -7,6 +7,11 @@ def drop_temporal_triggers(table_name)
         execute "drop trigger #{table_name}_ai on #{table_name}"
         execute "drop trigger #{table_name}_au on #{table_name}"
         execute "drop trigger #{table_name}_ad on #{table_name}"
+
+        # remove functions that where created, too
+        execute "drop function #{table_name}_ai()"
+        execute "drop function #{table_name}_au()"
+        execute "drop function #{table_name}_ad()"
       end
 
       def create_temporal_triggers(table_name, primary_key) # rubocop:disable Metrics/MethodLength

lib/temporal_tables/temporal_adapter.rb

@@ -74,7 +74,7 @@ def remove_temporal_table(table_name)
       return unless table_exists?(temporal_name(table_name))
 
       drop_temporal_triggers table_name
-      drop_table_without_temporal temporal_name(table_name)
+      drop_table temporal_name(table_name)
     end
 
     def drop_table(table_name, **options)

spec/support/database.rb

@@ -1,13 +1,43 @@
 # frozen_string_literal: true
 
-module TemporalTables
-  module DatabaseAdapter
-    def self.adapter_name
-      if Gemika::Env.gem?('pg')
-        'postgresql'
-      elsif Gemika::Env.gem?('mysql2')
-        'mysql'
-      end
+def adapter_name
+  if Gemika::Env.gem?('pg')
+    'postgresql'
+  elsif Gemika::Env.gem?('mysql2')
+    'mysql'
+  else
+    raise 'Cannot determine adapter'
+  end
+end
+
+def table_exists?(name)
+  ActiveRecord::Base.connection.table_exists?(name)
+end
+
+def function_exists?(name)
+  case adapter_name
+  when 'postgresql'
+    begin
+      ActiveRecord::Base.connection.execute("select(pg_get_functiondef('#{name}'::regprocedure))").present?
+    rescue ActiveRecord::StatementInvalid
+      false
     end
+  when 'mysql' then raise NotImplementedError
+  else raise "Unknown adapter #{adapter_name}"
+  end
+end
+
+def trigger_exists?(name) # rubocop:disable Metrics/MethodLength
+  case adapter_name
+  when 'postgresql'
+    ActiveRecord::Base.connection.execute(
+      "select (pg_get_triggerdef(oid)) FROM pg_trigger WHERE tgname = '#{name}'"
+    ).first.present?
+  when 'mysql'
+    ActiveRecord::Base.connection.execute(
+      'SHOW TRIGGERS FROM temporal_tables_test'
+    ).find { |row| row.first == name }.present?
+  else
+    raise "Unknown adapter #{adapter_name}"
   end
 end

spec/temporal_tables/temporal_adapter_spec.rb

@@ -0,0 +1,32 @@
+# frozen_string_literal: true
+
+require 'spec_helper'
+
+describe TemporalTables::TemporalAdapter do
+  describe '#remove_temporal_table' do
+    it 'correctly removes history table, functions and triggers' do
+      skip 'mysql has no functions' if adapter_name == 'mysql'
+
+      expect do
+        ActiveRecord::Schema.define { remove_temporal_table :people }
+      end.to change { table_exists?('people_h') }.from(true).to(false)
+         .and change { function_exists?('people_ai()') }.from(true).to(false)
+         .and change { function_exists?('people_au()') }.from(true).to(false)
+         .and change { function_exists?('people_ad()') }.from(true).to(false)
+         .and change { trigger_exists?('people_ai') }.from(true).to(false)
+         .and change { trigger_exists?('people_au') }.from(true).to(false)
+         .and change { trigger_exists?('people_ad') }.from(true).to(false)
+    end
+
+    it 'correctly removes history table and triggers' do
+      skip 'other adapters than mysql have functions, too' if adapter_name != 'mysql'
+
+      expect do
+        ActiveRecord::Schema.define { remove_temporal_table :people }
+      end.to change { table_exists?('people_h') }.from(true).to(false)
+         .and change { trigger_exists?('people_ai') }.from(true).to(false)
+         .and change { trigger_exists?('people_au') }.from(true).to(false)
+         .and change { trigger_exists?('people_ad') }.from(true).to(false)
+    end
+  end
+end