ci: add jruby (#193)

Author: supercaracal

.github/workflows/test.yaml

@@ -35,6 +35,7 @@ jobs:
           - {redis: '6.2', ruby: '3.1'}
           - {redis: '6.2', ruby: '3.0'}
           - {redis: '5.0', ruby: '2.7'}
+          - {ruby: 'jruby'}
           - {task: test_cluster_state,  redis: '7.0', replica: '2', compose: compose.replica.yaml}
           - {task: test_cluster_state,  redis: '6.2', replica: '2', compose: compose.replica.yaml}
           - {task: test_cluster_broken, redis: '7.0', restart: 'no'}

test/test_concurrency.rb

@@ -17,6 +17,8 @@ def teardown
   end
 
   def test_forking
+    skip("fork is not available on #{RUBY_ENGINE}") if %w[jruby].include?(RUBY_ENGINE)
+
     pids = Array.new(MAX_THREADS) do
       Process.fork do
         ATTEMPTS.times { MAX_THREADS.times { |i| @client.call('INCR', "key#{i}") } }
@@ -34,6 +36,8 @@ def test_forking
   end
 
   def test_forking_with_pipelining
+    skip("fork is not available on #{RUBY_ENGINE}") if %w[jruby].include?(RUBY_ENGINE)
+
     pids = Array.new(MAX_THREADS) do
       Process.fork do
         @client.pipelined { |pi| ATTEMPTS.times { MAX_THREADS.times { |i| pi.call('INCR', "key#{i}") } } }