Ignore frozen string literal warning in ruby-head(3.4.0dev) and the P…

…rettyPrint#text (#177)

Fixes #176

https://bugs.ruby-lang.org/issues/20205
ruby/ruby#10262

test/helper.rb

@@ -3,6 +3,7 @@
 
 require 'stringio'
 require 'warning'
+require 'prettyprint'
 
 # How to use => https://test-unit.github.io/test-unit/en/
 require 'test/unit'
@@ -14,13 +15,16 @@
   Warning.ignore(//, path)
 end
 
+# https://github.com/kachick/irb-power_assert/issues/176
+# https://github.com/ruby/ruby/blob/e5b585ba908d371c67d97988795a5e40ec2f9e93/lib/prettyprint.rb#L184
+Warning.ignore(/literal string will be frozen in the future/, PrettyPrint.instance_method(:text).source_location.first)
+
 Warning.process do |_warning|
   :raise
 end
 
 require_relative '../lib/irb-power_assert'
 
-
 class Test::Unit::TestCase
   # Taken from https://github.com/ruby/irb/blob/ad08152c43d4309ee4dec3bbaf361ffc338c1f46/test/lib/minitest/unit.rb#L461-L495, thank you!
   def capture_io