Bug Report for JRuby: Fiber#new still creates new Threads

.rspec

@@ -1,3 +1,4 @@
 --format documentation
 --color
 --require spec_helper
+--tag ~with_jdbc

Gemfile

@@ -4,7 +4,19 @@ source "https://rubygems.org"
 gemspec
 
 gem "database_cleaner-core", git: "https://github.com/DatabaseCleaner/database_cleaner"
-gem "byebug"
+
+group :cruby_only do
+  gem "byebug"
+  gem "mysql2"
+  gem "pg"
+  gem "sqlite3"
+end
+
+group :development do
+  gem "bundler"
+  gem "rake"
+  gem "rspec"
+end
 
 group :test do
   gem "simplecov", require: false

database_cleaner-sequel.gemspec

@@ -20,11 +20,4 @@ Gem::Specification.new do |spec|
 
   spec.add_dependency "database_cleaner-core", "~>2.0.0"
   spec.add_dependency "sequel"
-
-  spec.add_development_dependency "bundler"
-  spec.add_development_dependency "rake"
-  spec.add_development_dependency "rspec"
-  spec.add_development_dependency "mysql2"
-  spec.add_development_dependency "pg"
-  spec.add_development_dependency "sqlite3"
 end

spec/database_cleaner/sequel/jdbc_transaction_spec.rb

@@ -0,0 +1,117 @@
+require 'database_cleaner/sequel/transaction'
+require 'database_cleaner/spec'
+require 'sequel'
+require 'database_cleaner/spec/database_helper'
+require 'ostruct'
+
+if RUBY_PLATFORM == 'java'
+  require_relative '../../support/postgresql-42.3.0.jar'
+
+  class SequelHelper < DatabaseCleaner::Spec::DatabaseHelper
+    private
+
+    def establish_connection(_config = default_config)
+      @connection = ::Sequel.connect(
+        # 'postgres://database_cleaner:[email protected]:5433/database_cleaner_test'
+        'jdbc:postgresql://127.0.0.1:5433/database_cleaner_test?user=database_cleaner&password=database_cleaner'
+      )
+    end
+  end
+end
+
+module DatabaseCleaner
+  module Sequel
+    RSpec.describe Transaction, :with_jdbc do
+      it_should_behave_like "a database_cleaner strategy"
+
+      SequelHelper.with_all_dbs do |helper|
+        next unless helper.db == :postgres
+
+        context "using a #{helper.db} connection" do
+          around do |example|
+            helper.setup
+            example.run
+            helper.teardown
+          end
+
+          let(:connection) { helper.connection }
+
+          before { subject.db = connection }
+
+          context "cleaning" do
+            it "should clean database" do
+              subject.cleaning do
+                connection[:users].insert
+                expect(connection[:users].count).to eq(1)
+              end
+
+              expect(connection[:users]).to be_empty
+            end
+
+            it "should work with nested transaction" do
+              subject.cleaning do
+                begin
+                  connection.transaction do
+                    connection[:users].insert
+                    connection[:users].insert
+
+                    expect(connection[:users].count).to eq(2)
+                    raise ::Sequel::Rollback
+                  end
+                rescue
+                end
+
+                connection[:users].insert
+                expect(connection[:users].count).to eq(1)
+              end
+
+              expect(connection[:users]).to be_empty
+            end
+          end
+
+          context "start/clean" do
+            it "should clean database" do
+              subject.start
+
+              connection[:users].insert
+              expect(connection[:users].count).to eq(1)
+
+              subject.clean
+
+              expect(connection[:users]).to be_empty
+            end
+
+            it "should work with nested transaction" do
+              subject.start
+              begin
+                connection.transaction do
+                  connection[:users].insert
+                  connection[:users].insert
+
+                  expect(connection[:users].count).to eq(2)
+                  raise ::Sequel::Rollback
+                end
+              rescue
+              end
+
+              connection[:users].insert
+              expect(connection[:users].count).to eq(1)
+
+              subject.clean
+
+              expect(connection[:users]).to be_empty
+            end
+          end
+        end
+      end
+
+      describe "start" do
+        it "should start a transaction"
+      end
+
+      describe "clean" do
+        it "should finish a transaction"
+      end
+    end
+  end
+end

spec/spec_helper.rb

@@ -1,5 +1,4 @@
 require "bundler/setup"
-require "byebug"
 
 if ENV['COVERAGE'] == 'true'
   require "simplecov"