Configure sqlite3 to use ~> 1.4 for rails 6+

test/support/ruby_2_6_rails_4_2_patch.rb

@@ -0,0 +1,16 @@
+# frozen_string_literal: true
+
+if RUBY_VERSION >= '2.6.0'
+  if Rails::VERSION::MAJOR < 5
+    class ActionController::TestResponse < ActionDispatch::TestResponse
+      def recycle!
+        # hack to avoid MonitorMixin double-initialize error:
+        @mon_mutex_owner_object_id = nil
+        @mon_mutex = nil
+        initialize
+      end
+    end
+  else
+    puts "Monkeypatch for ActionController::TestResponse no longer needed"
+  end
+end

test/test_helper.rb

@@ -56,6 +56,8 @@ end
 
 require 'support/rails_app'
 
+require 'support/ruby_2_6_rails_4_2_patch'
+
 # require "rails/test_help"
 
 require 'support/serialization_testing'