How to check the compatible Ruby versions for a gem

Question

How do I find out if a particular gem is compatible with a certain Ruby version or not?

I want to upgrade the Ruby version of an application I am working on, But I did n

Answer 1

Looking for the gemspec file and checking RubyGems.org is a good way to check Ruby compatibility, but as mentioned above, it would be useless if a gem author didn't write a gemspec file.

If you using a Ruby version management system like RVM or rbenv, making a simple testing script would be a solution. If Ruby version 2.4.1 and 2.5.1 have been installed on your local machine, write a script similar to "Testing With Multiple Ruby And Gem Versions" like:

#!/usr/bin/env bash

set -e

rubies=("ruby-2.4.1" "ruby-2.5.3")
for i in "${rubies[@]}"
do
  echo "====================================================="
  echo "$i: Start Test"
  echo "====================================================="
  rvm $i exec bundle
  rvm $i exec bundle exec rake test
  echo "====================================================="
  echo "$i: End Test"
  echo "====================================================="
done

RVM will select a Ruby version and run the test for the selected Ruby version.

If a gem doesn't have any unit tests, this test script would be useless, too. But a gem that doesn't have any unit test would not be worth using.

Although, this solution isn't an authentic way of checking for a compatible Ruby version either, it'd be worth using for your testing.