diff --git a/Gemfile b/Gemfile
index 5bd18f4..3a5e7c7 100644
--- a/Gemfile
+++ b/Gemfile
@@ -14,3 +14,4 @@ gem "redis"
 gem "connection_pool"
 gem "kaminari"
 gem "elasticsearch-xpack", ">= 7.8.0"
+gem "parallel_tests"
diff --git a/Rakefile b/Rakefile
index 35dafa0..d461308 100644
--- a/Rakefile
+++ b/Rakefile
@@ -7,3 +7,7 @@ Rake::TestTask.new do |t|
   t.pattern = "test/**/*_test.rb"
   t.warning = false
 end
+
+# to test in parallel, uncomment and run:
+# rake parallel:test
+# require "parallel_tests/tasks"
diff --git a/test/inheritance_test.rb b/test/inheritance_test.rb
index 45f6be9..83792cc 100644
--- a/test/inheritance_test.rb
+++ b/test/inheritance_test.rb
@@ -13,7 +13,7 @@ class InheritanceTest < Minitest::Test
   end
 
   def test_child_index_name
-    assert_equal "animals-#{Date.today.year}", Dog.searchkick_index.name
+    assert_equal "animals-#{Date.today.year}#{ENV["TEST_ENV_NUMBER"]}", Dog.searchkick_index.name
   end
 
   def test_child_search
--
libgit2 0.21.0