diff --git a/.travis.yml b/.travis.yml
index 426ccf85a..79ae349f7 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -10,6 +10,7 @@ language: ruby
 
 services:
   - mongodb
+  - elasticsearch
 
 branches:
   only:
@@ -23,29 +24,40 @@ matrix:
   include:
     - rvm: 2.2
       jdk: oraclejdk8
-      env: TEST_SUITE=unit
+      env: RAILS_VERSIONS=3.0
 
     - rvm: 2.3
       jdk: oraclejdk8
-      env: TEST_SUITE=unit
+      env: RAILS_VERSIONS=5.0
 
     - rvm: 2.4
       jdk: oraclejdk8
-      env: TEST_SUITE=unit
+      env: RAILS_VERSIONS=5.0
 
     - rvm: 2.5
       jdk: oraclejdk8
-      env: TEST_SUITE=unit
+      env: RAILS_VERSIONS=5.0
 
     - rvm: jruby-9.1
       jdk: oraclejdk8
-      env: TEST_SUITE=unit
+      env: RAILS_VERSIONS=5.0
 
     - rvm: 2.5
       jdk: oraclejdk8
-      env: TEST_SUITE=integration QUIET=y
+      env: RAILS_VERSIONS=4.0,5.0
+
+env:
+  global:
+    - ELASTICSEARCH_VERSION=6.4.0
+    - QUIET=true
+
 
 before_install:
+  - wget https://artifacts.elastic.co/downloads/elasticsearch/elasticsearch-${ELASTICSEARCH_VERSION}.deb
+  - wget https://artifacts.elastic.co/downloads/elasticsearch/elasticsearch-${ELASTICSEARCH_VERSION}.deb.sha512
+  - shasum -a 512 -c elasticsearch-${ELASTICSEARCH_VERSION}.deb.sha512
+  - sudo dpkg -i --force-confnew elasticsearch-${ELASTICSEARCH_VERSION}.deb
+  - sudo service elasticsearch restart
   - gem update --system -q
   - gem update bundler -q
   - gem --version
@@ -57,7 +69,7 @@ install:
   - rake bundle:install
 
 script:
-  - rake test:$TEST_SUITE
+  - rake test:all
 
 notifications:
   disable: true
diff --git a/Rakefile b/Rakefile
index bfca05bfd..6020f304d 100644
--- a/Rakefile
+++ b/Rakefile
@@ -1,6 +1,7 @@
 require 'pathname'
 
-subprojects = %w| elasticsearch-rails elasticsearch-persistence elasticsearch-model |
+subprojects = [ 'elasticsearch-rails', 'elasticsearch-persistence' ]
+subprojects << 'elasticsearch-model' unless defined?(JRUBY_VERSION)
 
 __current__ = Pathname( File.expand_path('..', __FILE__) )
 
@@ -25,15 +26,9 @@ namespace :bundle do
   task :install do
     subprojects.each do |project|
       puts '-'*80
-      sh "bundle install --gemfile #{__current__.join(project)}/Gemfile"
+      sh "cd #{__current__.join(project)} && bundle exec rake bundle:install"
       puts
     end
-    puts '-'*80
-    sh "bundle install --gemfile #{__current__.join('elasticsearch-model/gemfiles')}/3.0.gemfile"
-    puts '-'*80
-    sh "bundle install --gemfile #{__current__.join('elasticsearch-model/gemfiles')}/4.0.gemfile"
-    puts '-'*80
-    sh "bundle install --gemfile #{__current__.join('elasticsearch-model/gemfiles')}/5.0.gemfile"
   end
 
   desc "Remove Gemfile.lock in all subprojects"
@@ -60,7 +55,7 @@ namespace :test do
   end
 
   desc "Run Elasticsearch (Docker)"
-  task :setup_elasticsearch do
+  task :setup_elasticsearch_docker do
     begin
       sh <<-COMMAND.gsub(/^\s*/, '').gsub(/\s{1,}/, ' ')
           docker run -d=true \
@@ -70,15 +65,30 @@ namespace :test do
             --env "cluster.routing.allocation.disk.threshold_enabled=false" \
             --publish 9250:9200 \
             --rm \
-            docker.elastic.co/elasticsearch/elasticsearch:6.4.0
+            docker.elastic.co/elasticsearch/elasticsearch:${ELASTICSEARCH_VERSION}
       COMMAND
       require 'elasticsearch/extensions/test/cluster'
-      Elasticsearch::Extensions::Test::Cluster::Cluster.new(version: '6.4.0',
+      Elasticsearch::Extensions::Test::Cluster::Cluster.new(version: ENV['ELASTICSEARCH_VERSION'],
                                                             number_of_nodes: 1).wait_for_green
     rescue
     end
   end
 
+  desc "Setup MongoDB (Docker)"
+  task :setup_mongodb_docker do
+    begin
+      if ENV['MONGODB_VERSION']
+        sh <<-COMMAND.gsub(/^\s*/, '').gsub(/\s{1,}/, ' ')
+            wget http://fastdl.mongodb.org/linux/mongodb-linux-x86_64-${MONGODB_VERSION}.tgz -O /tmp/mongodb.tgz &&
+            tar -xvf /tmp/mongodb.tgz &&
+            mkdir /tmp/data &&
+            ${PWD}/mongodb-linux-x86_64-${MONGODB_VERSION}/bin/mongod --setParameter enableTestCommands=1 --dbpath /tmp/data --bind_ip 127.0.0.1 --auth &> /dev/null &
+        COMMAND
+      end
+    rescue
+    end
+  end
+
   desc "Run integration tests in all subprojects"
   task :integration => :setup_elasticsearch do
     # 1/ elasticsearch-model
@@ -106,8 +116,13 @@ namespace :test do
 
   desc "Run all tests in all subprojects"
   task :all do
-    Rake::Task['test:unit'].invoke
-    Rake::Task['test:integration'].invoke
+    subprojects.each do |project|
+      puts '-'*80
+      sh "cd #{project} && " +
+             "unset BUNDLE_GEMFILE && " +
+             "bundle exec rake test:all"
+      puts "\n"
+    end
   end
 
   namespace :cluster do
diff --git a/elasticsearch-model/Rakefile b/elasticsearch-model/Rakefile
index e479d3599..6969c1d4a 100644
--- a/elasticsearch-model/Rakefile
+++ b/elasticsearch-model/Rakefile
@@ -4,12 +4,25 @@ desc "Run unit tests"
 task :default => 'test:unit'
 task :test    => 'test:unit'
 
-namespace :bundler do
-  desc "Install dependencies for all the Gemfiles"
+if RUBY_VERSION < '2.3'
+  GEMFILES = ['3.0.gemfile', '4.0.gemfile', '5.0.gemfile']
+else
+  GEMFILES = ['4.0.gemfile', '5.0.gemfile']
+end
+
+namespace :bundle do
+  desc 'Install dependencies for all the Gemfiles in /gemfiles. Optionally define env variable RAILS_VERSIONS. E.g. RAILS_VERSIONS=3.0,5.0'
   task :install do
-    sh "BUNDLE_GEMFILE='#{File.expand_path('../gemfiles/3.0.gemfile', __FILE__)}' bundle install"
-    sh "BUNDLE_GEMFILE='#{File.expand_path('../gemfiles/4.0.gemfile', __FILE__)}' bundle install"
-    sh "BUNDLE_GEMFILE='#{File.expand_path('../gemfiles/5.0.gemfile', __FILE__)}' bundle install"
+    unless defined?(JRUBY_VERSION)
+      puts '-'*80
+      gemfiles = ENV['RAILS_VERSIONS'] ? ENV['RAILS_VERSIONS'].split(',').map { |v| "#{v}.gemfile"} : GEMFILES
+      gemfiles.each do |gemfile|
+        Bundler.with_clean_env do
+          sh "bundle install --gemfile #{File.expand_path('../gemfiles/'+gemfile, __FILE__)}"
+        end
+        puts '-'*80
+      end
+    end
   end
 end
 
@@ -18,38 +31,16 @@ end
 require 'rake/testtask'
 namespace :test do
 
-  Rake::TestTask.new(:run_unit) do |test|
-    test.libs << 'lib' << 'test'
-    test.test_files = FileList["test/unit/**/*_test.rb"]
-    test.verbose = false
-    test.warning = false
-  end
-
-  Rake::TestTask.new(:run_integration) do |test|
-    test.libs << 'lib' << 'test'
-    test.test_files = FileList["test/integration/**/*_test.rb"]
-    test.verbose = false
-    test.warning = false
-  end
-
-  desc "Run unit tests against ActiveModel 3, 4 and 5"
-  task :unit do
-  end
-
-  desc "Run integration tests against latest stable ActiveModel (5)"
-  task :integration do
-    ['3.0.gemfile', '4.0.gemfile', '5.0.gemfile'].each do |gemfile|
-      ['bundle exec rake test:run_unit', 'bundle exec rspec'].each do |cmd|
-        sh "BUNDLE_GEMFILE='#{File.expand_path('../gemfiles/'+gemfile, __FILE__)}' #{cmd}"
-      end
+  desc 'Run all tests. Optionally define env variable RAILS_VERSIONS. E.g. RAILS_VERSIONS=3.0,5.0'
+  task :all, [:rails_versions] do |task, args|
+    gemfiles = ENV['RAILS_VERSIONS'] ? ENV['RAILS_VERSIONS'].split(',').map {|v| "#{v}.gemfile"} : GEMFILES
+    puts '-' * 80
+    gemfiles.each do |gemfile|
+      sh "BUNDLE_GEMFILE='#{File.expand_path("../gemfiles/#{gemfile}", __FILE__)}' " +
+             " bundle exec rspec"
+      puts '-' * 80
     end
   end
-
-  desc "Run unit and integration tests"
-  task :all do
-    Rake::Task['test:unit'].invoke
-    Rake::Task['test:integration'].invoke
-  end
 end
 
 # ----- Documentation tasks ---------------------------------------------------
diff --git a/elasticsearch-model/spec/spec_helper.rb b/elasticsearch-model/spec/spec_helper.rb
index 178f9c9fe..9e46a27de 100644
--- a/elasticsearch-model/spec/spec_helper.rb
+++ b/elasticsearch-model/spec/spec_helper.rb
@@ -10,6 +10,10 @@
 require 'yaml'
 require 'active_record'
 
+unless defined?(ELASTICSEARCH_URL)
+  ELASTICSEARCH_URL = ENV['ELASTICSEARCH_URL'] || "localhost:#{(ENV['TEST_CLUSTER_PORT'] || 9200)}"
+end
+
 RSpec.configure do |config|
   config.formatter = 'documentation'
   config.color = true
@@ -18,7 +22,7 @@
     require 'ansi'
     tracer = ::Logger.new(STDERR)
     tracer.formatter = lambda { |s, d, p, m| "#{m.gsub(/^.*$/) { |n| '   ' + n }.ansi(:faint)}\n" }
-    Elasticsearch::Model.client = Elasticsearch::Client.new host: "localhost:#{(ENV['TEST_CLUSTER_PORT'] || 9250)}",
+    Elasticsearch::Model.client = Elasticsearch::Client.new host: ELASTICSEARCH_URL,
                                                             tracer: (ENV['QUIET'] ? nil : tracer)
 
     unless ActiveRecord::Base.connected?
diff --git a/elasticsearch-persistence/Rakefile b/elasticsearch-persistence/Rakefile
index 660e57211..0942fbdcf 100644
--- a/elasticsearch-persistence/Rakefile
+++ b/elasticsearch-persistence/Rakefile
@@ -12,19 +12,22 @@ require 'rspec/core/rake_task'
 namespace :test do
 
   RSpec::Core::RakeTask.new(:spec)
-  Rake::TestTask.new(:unit) do |test|
-  end
 
-  Rake::TestTask.new(:integration) do |test|
+  Rake::TestTask.new(:all) do |test|
     test.verbose = false
     test.warning = false
     test.deps = [ :spec ]
   end
+end
 
-  Rake::TestTask.new(:all) do |test|
-    test.verbose = false
-    test.warning = false
-    test.deps = [ :spec ]
+namespace :bundle do
+  desc 'Install gem dependencies'
+  task :install do
+    puts '-'*80
+    Bundler.with_clean_env do
+      sh 'bundle install'
+    end
+    puts '-'*80
   end
 end
 
diff --git a/elasticsearch-persistence/spec/spec_helper.rb b/elasticsearch-persistence/spec/spec_helper.rb
index 9f2f0f5df..6b8ea8182 100644
--- a/elasticsearch-persistence/spec/spec_helper.rb
+++ b/elasticsearch-persistence/spec/spec_helper.rb
@@ -1,6 +1,10 @@
 require 'pry-nav'
 require 'elasticsearch/persistence'
 
+unless defined?(ELASTICSEARCH_URL)
+  ELASTICSEARCH_URL = ENV['ELASTICSEARCH_URL'] || "localhost:#{(ENV['TEST_CLUSTER_PORT'] || 9200)}"
+end
+
 RSpec.configure do |config|
   config.formatter = 'documentation'
   config.color = true
@@ -13,7 +17,7 @@
 # The default client to be used by the repositories.
 #
 # @since 6.0.0
-DEFAULT_CLIENT = Elasticsearch::Client.new(host: "localhost:#{(ENV['TEST_CLUSTER_PORT'] || 9250)}",
+DEFAULT_CLIENT = Elasticsearch::Client.new(host: ELASTICSEARCH_URL,
                                            tracer: (ENV['QUIET'] ? nil : ::Logger.new(STDERR)))
 
 class MyTestRepository
diff --git a/elasticsearch-rails/Rakefile b/elasticsearch-rails/Rakefile
index 622731c66..f555aaf42 100644
--- a/elasticsearch-rails/Rakefile
+++ b/elasticsearch-rails/Rakefile
@@ -28,6 +28,17 @@ namespace :test do
   end
 end
 
+namespace :bundle do
+  desc 'Install gem dependencies'
+  task :install do
+    puts '-'*80
+    Bundler.with_clean_env do
+      sh 'bundle install'
+    end
+    puts '-'*80
+  end
+end
+
 # ----- Documentation tasks ---------------------------------------------------
 
 require 'yard'
diff --git a/elasticsearch-rails/test/test_helper.rb b/elasticsearch-rails/test/test_helper.rb
index e06554fc0..bc96002c5 100644
--- a/elasticsearch-rails/test/test_helper.rb
+++ b/elasticsearch-rails/test/test_helper.rb
@@ -1,4 +1,7 @@
 RUBY_1_8 = defined?(RUBY_VERSION) && RUBY_VERSION < '1.9'
+unless defined?(ELASTICSEARCH_URL)
+  ELASTICSEARCH_URL = ENV['ELASTICSEARCH_URL'] || "localhost:#{(ENV['TEST_CLUSTER_PORT'] || 9200)}"
+end
 
 exit(0) if RUBY_1_8
 
@@ -56,7 +59,7 @@ def setup
         tracer = ::Logger.new(STDERR)
         tracer.formatter = lambda { |s, d, p, m| "#{m.gsub(/^.*$/) { |n| '   ' + n }.ansi(:faint)}\n" }
 
-        Elasticsearch::Model.client = Elasticsearch::Client.new host: "localhost:#{(ENV['TEST_CLUSTER_PORT'] || 9250)}",
+        Elasticsearch::Model.client = Elasticsearch::Client.new host: ELASTICSEARCH_URL,
                                                                 tracer: (ENV['QUIET'] ? nil : tracer)
       end
     end