Attempt to reduce non-deterministic output

Author: schneems

buildpacks/ruby/tests/integration_test.rs

@@ -191,6 +191,11 @@ fn test_default_app_ubuntu20() {
             STDERR.sync = true
 
             task "assets:precompile" do
+              # Non-determinism in output https://github.com/heroku/buildpacks-ruby/issues/409
+              STDOUT.puts
+              STDERR.puts
+              sleep 0.1
+
               puts "START RAKE TEST OUTPUT"
               run!("echo $PATH")
               run!("which -a rake")