Fix some issues from a recent PR

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 temporal_name(table_name)
+      drop_table_without_temporal temporal_name(table_name)
     end
 
     def drop_table(table_name, **options)

spec/basic_history_spec.rb

@@ -207,7 +207,7 @@
     end
   end
 
-  if TemporalTables::DatabaseAdapter.adapter_name != 'mysql'
+  if TemporalTables::DatabaseHelper.adapter_name != 'mysql'
     describe 'when changing a creature with an array column' do
       let!(:cat) { Cat.create name: 'Mr. Mittens', nicknames: %w[Blacky Kitty] }
 

spec/spec_helper.rb

@@ -9,17 +9,9 @@
 READ_DATABASE_CONFIG_LOCATION = 'spec/internal/config/database.ci.yml'
 WRITE_DATABASE_CONFIG_LOCATION = 'spec/internal/config/database.yml'
 
-def adapter_name
-  if Gemika::Env.gem?('mysql2')
-    'mysql'
-  else
-    'postgresql'
-  end
-end
-
 def database_config_from_gems(file_location)
   config = YAML.load_file(file_location)
-  data = config.slice(adapter_name)
+  data = config.slice(TemporalTables::DatabaseHelper.adapter_name)
   { Rails.env.to_s => data }
 end
 
@@ -31,7 +23,7 @@ def database_config_from_gems(file_location)
   database_config_from_gems(READ_DATABASE_CONFIG_LOCATION).to_yaml
 )
 
-Rails.env = adapter_name
+Rails.env = TemporalTables::DatabaseHelper.adapter_name
 database = Gemika::Database.new
 database.connect
 

spec/support/database_helper.rb

@@ -0,0 +1,47 @@
+# frozen_string_literal: true
+
+module TemporalTables
+  module DatabaseHelper
+    def self.adapter_name
+      if Gemika::Env.gem?('pg')
+        'postgresql'
+      elsif Gemika::Env.gem?('mysql2')
+        'mysql'
+      else
+        raise 'Cannot determine adapter'
+      end
+    end
+
+    def self.table_exists?(name)
+      ActiveRecord::Base.connection.table_exists?(name)
+    end
+
+    def self.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 self.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
+  end
+end

spec/temporal_tables/temporal_adapter_spec.rb

@@ -5,28 +5,28 @@
 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'
+      skip 'mysql has no functions' if TemporalTables::DatabaseHelper.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.to change { TemporalTables::DatabaseHelper.table_exists?('people_h') }.from(true).to(false)
+         .and change { TemporalTables::DatabaseHelper.function_exists?('people_ai()') }.from(true).to(false)
+         .and change { TemporalTables::DatabaseHelper.function_exists?('people_au()') }.from(true).to(false)
+         .and change { TemporalTables::DatabaseHelper.function_exists?('people_ad()') }.from(true).to(false)
+         .and change { TemporalTables::DatabaseHelper.trigger_exists?('people_ai') }.from(true).to(false)
+         .and change { TemporalTables::DatabaseHelper.trigger_exists?('people_au') }.from(true).to(false)
+         .and change { TemporalTables::DatabaseHelper.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'
+      skip 'other adapters than mysql have functions, too' if TemporalTables::DatabaseHelper.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.to change { TemporalTables::DatabaseHelper.table_exists?('people_h') }.from(true).to(false)
+         .and change { TemporalTables::DatabaseHelper.trigger_exists?('people_ai') }.from(true).to(false)
+         .and change { TemporalTables::DatabaseHelper.trigger_exists?('people_au') }.from(true).to(false)
+         .and change { TemporalTables::DatabaseHelper.trigger_exists?('people_ad') }.from(true).to(false)
     end
   end
 end