Use better condition for the old ruby versions

1 files changed, 2 insertions, 2 deletions

diff --git a/tests/lib/envutil.rb b/tests/lib/envutil.rb
index 63e23ba..937e112 100644
--- a/tests/lib/envutil.rb
+++ b/tests/lib/envutil.rb
@@ -53,7 +53,7 @@ module EnvUtil
       @original_internal_encoding = Encoding.default_internal
       @original_external_encoding = Encoding.default_external
       @original_verbose = $VERBOSE
-      @original_warning = %i[deprecated experimental].to_h {|i| [i, Warning[i]]} if RUBY_VERSION > "2.7"
+      @original_warning = defined?(Warning.[]) ? %i[deprecated experimental].to_h {|i| [i, Warning[i]]} : nil
     end
   end
 
@@ -211,7 +211,7 @@ module EnvUtil
   ensure
     stderr, $stderr = $stderr, stderr
     $VERBOSE = EnvUtil.original_verbose
-    EnvUtil.original_warning.each {|i, v| Warning[i] = v}
+    EnvUtil.original_warning&.each {|i, v| Warning[i] = v}
   end
   module_function :verbose_warning