diff --git a/.github/workflows/ruby.yml b/.github/workflows/ruby.yml
index dfe29097..265a1b60 100644
--- a/.github/workflows/ruby.yml
+++ b/.github/workflows/ruby.yml
@@ -17,22 +17,35 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        ruby_version: [3.3, 3.2, 3.1, '3.0', jruby]
+        ruby_version: [head, 3.3, 3.2, 3.1, '3.0', jruby]
         gemfile:
           - Gemfile
           - gemfiles/Gemfile.rails-6.0.x
           - gemfiles/Gemfile.rails-6.1.x
           - gemfiles/Gemfile.rails-7.0.x
           - gemfiles/Gemfile.rails-7.1.x
+          - gemfiles/Gemfile.rails-7.2.x
+          - gemfiles/Gemfile.rails-8.0.x
           - gemfiles/Gemfile.rails-main
         exclude:
-          # Ruby 3.0 is not supported by Rails main (requires at least Ruby 3.1)
+          # Rails 8+ requires at least Ruby 3.2
+          - ruby_version: '3.1'
+            gemfile: gemfiles/Gemfile.rails-main
           - ruby_version: '3.0'
             gemfile: gemfiles/Gemfile.rails-main
+          - ruby_version: '3.1'
+            gemfile: gemfiles/Gemfile.rails-8.0.x
+          - ruby_version: '3.0'
+            gemfile: gemfiles/Gemfile.rails-8.0.x
+          # Rails 7.2.x requires at least Ruby 3.1
+          - ruby_version: '3.0'
+            gemfile: gemfiles/Gemfile.rails-7.2.x
           # JRuby is not supported by Rails 7.0.x
           - ruby_version: jruby
             gemfile: gemfiles/Gemfile.rails-7.0.x
-          # JRuby is not supported by Rails main
+          # JRuby is not supported by Rails 8+
+          - ruby_version: jruby
+            gemfile: gemfiles/Gemfile.rails-8.0.x
           - ruby_version: jruby
             gemfile: gemfiles/Gemfile.rails-main
 
diff --git a/gemfiles/Gemfile.rails-6.1.x b/gemfiles/Gemfile.rails-6.1.x
index 6f67f785..43481a60 100644
--- a/gemfiles/Gemfile.rails-6.1.x
+++ b/gemfiles/Gemfile.rails-6.1.x
@@ -8,6 +8,8 @@ gem 'test_declarative', '0.0.6'
 gem 'rake'
 gem 'minitest', '~> 5.14'
 gem 'racc'
+gem 'base64'
+gem 'mutex_m'
 
 platforms :mri do
   gem 'oj'
diff --git a/gemfiles/Gemfile.rails-7.2.x b/gemfiles/Gemfile.rails-7.2.x
new file mode 100644
index 00000000..a4a00efe
--- /dev/null
+++ b/gemfiles/Gemfile.rails-7.2.x
@@ -0,0 +1,14 @@
+source 'https://rubygems.org'
+
+gemspec :path => '..'
+
+gem 'activesupport', '~> 7.2'
+gem 'mocha', '~> 2'
+gem 'test_declarative', '0.0.6'
+gem 'rake'
+gem 'minitest', '~> 5.1'
+gem 'racc'
+
+platforms :mri do
+  gem 'oj'
+end
diff --git a/gemfiles/Gemfile.rails-8.0.x b/gemfiles/Gemfile.rails-8.0.x
new file mode 100644
index 00000000..16d4dba4
--- /dev/null
+++ b/gemfiles/Gemfile.rails-8.0.x
@@ -0,0 +1,14 @@
+source 'https://rubygems.org'
+
+gemspec :path => '..'
+
+gem 'activesupport', '~> 8.0'
+gem 'mocha', '~> 2'
+gem 'test_declarative', '0.0.6'
+gem 'rake'
+gem 'minitest', '~> 5.1'
+gem 'racc'
+
+platforms :mri do
+  gem 'oj'
+end
diff --git a/lib/i18n/tests/localization/procs.rb b/lib/i18n/tests/localization/procs.rb
index 7db45d1d..2c5d8e15 100644
--- a/lib/i18n/tests/localization/procs.rb
+++ b/lib/i18n/tests/localization/procs.rb
@@ -34,7 +34,7 @@ module Procs
         test "localize Date: given a format that resolves to a Proc it calls the Proc with the object and extra options" do
           setup_time_proc_translations
           date = ::Date.new(2008, 3, 1)
-          assert_equal '[Sat, 01 Mar 2008, {:foo=>"foo"}]', I18n.l(date, :format => :proc, :foo => 'foo', :locale => :ru)
+          assert_equal %|[Sat, 01 Mar 2008, #{{:foo=>"foo"}}]|, I18n.l(date, :format => :proc, :foo => 'foo', :locale => :ru)
         end
 
         test "localize DateTime: given a format that resolves to a Proc it calls the Proc with the object" do
@@ -46,7 +46,7 @@ module Procs
         test "localize DateTime: given a format that resolves to a Proc it calls the Proc with the object and extra options" do
           setup_time_proc_translations
           datetime = ::DateTime.new(2008, 3, 1, 6)
-          assert_equal '[Sat, 01 Mar 2008 06:00:00 +00:00, {:foo=>"foo"}]', I18n.l(datetime, :format => :proc, :foo => 'foo', :locale => :ru)
+          assert_equal %|[Sat, 01 Mar 2008 06:00:00 +00:00, #{{:foo=>"foo"}}]|, I18n.l(datetime, :format => :proc, :foo => 'foo', :locale => :ru)
         end
 
         test "localize Time: given a format that resolves to a Proc it calls the Proc with the object" do
diff --git a/lib/i18n/tests/procs.rb b/lib/i18n/tests/procs.rb
index db99c766..d377117d 100644
--- a/lib/i18n/tests/procs.rb
+++ b/lib/i18n/tests/procs.rb
@@ -5,34 +5,38 @@ module Tests
     module Procs
       test "lookup: given a translation is a proc it calls the proc with the key and interpolation values" do
         I18n.backend.store_translations(:en, :a_lambda => lambda { |*args| I18n::Tests::Procs.filter_args(*args) })
-        assert_equal '[:a_lambda, {:foo=>"foo"}]', I18n.t(:a_lambda, :foo => 'foo')
+        assert_equal %|[:a_lambda, #{{:foo=>"foo"}}]|, I18n.t(:a_lambda, :foo => 'foo')
       end
 
       test "lookup: given a translation is a proc it passes the interpolation values as keyword arguments" do
         I18n.backend.store_translations(:en, :a_lambda => lambda { |key, foo:, **| I18n::Tests::Procs.filter_args(key, foo: foo) })
-        assert_equal '[:a_lambda, {:foo=>"foo"}]', I18n.t(:a_lambda, :foo => 'foo')
+        assert_equal %|[:a_lambda, #{{:foo=>"foo"}}]|, I18n.t(:a_lambda, :foo => 'foo')
       end
 
       test "defaults: given a default is a Proc it calls it with the key and interpolation values" do
         proc = lambda { |*args| I18n::Tests::Procs.filter_args(*args) }
-        assert_equal '[nil, {:foo=>"foo"}]', I18n.t(nil, :default => proc, :foo => 'foo')
+        assert_equal %|[nil, #{{:foo=>"foo"}}]|, I18n.t(nil, :default => proc, :foo => 'foo')
       end
 
       test "defaults: given a default is a key that resolves to a Proc it calls it with the key and interpolation values" do
         the_lambda = lambda { |*args| I18n::Tests::Procs.filter_args(*args) }
         I18n.backend.store_translations(:en, :a_lambda => the_lambda)
-        assert_equal '[:a_lambda, {:foo=>"foo"}]', I18n.t(nil, :default => :a_lambda, :foo => 'foo')
-        assert_equal '[:a_lambda, {:foo=>"foo"}]', I18n.t(nil, :default => [nil, :a_lambda], :foo => 'foo')
+        assert_equal %|[:a_lambda, #{{:foo=>"foo"}}]|, I18n.t(nil, :default => :a_lambda, :foo => 'foo')
+        assert_equal %|[:a_lambda, #{{:foo=>"foo"}}]|, I18n.t(nil, :default => [nil, :a_lambda], :foo => 'foo')
       end
 
       test "interpolation: given an interpolation value is a lambda it calls it with key and values before interpolating it" do
         proc = lambda { |*args| I18n::Tests::Procs.filter_args(*args) }
-        assert_match %r(\[\{:foo=>#<Proc.*>\}\]), I18n.t(nil, :default => '%{foo}', :foo => proc)
+        if RUBY_VERSION < "3.4"
+          assert_match %r(\[\{:foo=>#<Proc.*>\}\]), I18n.t(nil, :default => '%{foo}', :foo => proc)
+        else
+          assert_match %r(\[\{foo: #<Proc.*>\}\]), I18n.t(nil, :default => '%{foo}', :foo => proc)
+        end
       end
 
       test "interpolation: given a key resolves to a Proc that returns a string then interpolation still works" do
         proc = lambda { |*args| "%{foo}: " + I18n::Tests::Procs.filter_args(*args) }
-        assert_equal 'foo: [nil, {:foo=>"foo"}]', I18n.t(nil, :default => proc, :foo => 'foo')
+        assert_equal %|foo: [nil, #{{:foo=>"foo"}}]|, I18n.t(nil, :default => proc, :foo => 'foo')
       end
 
       test "pluralization: given a key resolves to a Proc that returns valid data then pluralization still works" do
diff --git a/test/backend/exceptions_test.rb b/test/backend/exceptions_test.rb
index e19c8121..2973935c 100644
--- a/test/backend/exceptions_test.rb
+++ b/test/backend/exceptions_test.rb
@@ -31,6 +31,6 @@ def setup
 
   test "exceptions: MissingInterpolationArgument message includes missing key, provided keys and full string" do
     exception = I18n::MissingInterpolationArgument.new('key', {:this => 'was given'}, 'string')
-    assert_equal 'missing interpolation argument "key" in "string" ({:this=>"was given"} given)', exception.message
+    assert_equal %|missing interpolation argument "key" in "string" (#{{:this=>"was given"}} given)|, exception.message
   end
 end
diff --git a/test/backend/interpolation_compiler_test.rb b/test/backend/interpolation_compiler_test.rb
index 35acce38..68a634ca 100644
--- a/test/backend/interpolation_compiler_test.rb
+++ b/test/backend/interpolation_compiler_test.rb
@@ -88,7 +88,7 @@ def test_custom_missing_interpolation_argument_handler
     I18n.config.missing_interpolation_argument_handler = lambda do |key, values, string|
       "missing key is #{key}, values are #{values.inspect}, given string is '#{string}'"
     end
-    assert_equal %|first missing key is last, values are {:first=>"first"}, given string is '%{first} %{last}'|,
+    assert_equal %|first missing key is last, values are #{{:first=>"first"}.to_s}, given string is '%{first} %{last}'|,
         compile_and_interpolate('%{first} %{last}', :first => 'first')
   ensure
     I18n.config.missing_interpolation_argument_handler = old_handler
diff --git a/test/i18n/exceptions_test.rb b/test/i18n/exceptions_test.rb
index 771308d0..9029c17c 100644
--- a/test/i18n/exceptions_test.rb
+++ b/test/i18n/exceptions_test.rb
@@ -43,7 +43,7 @@ def test_invalid_locale_stores_locale
   test "InvalidPluralizationData message contains count, data and missing key" do
     force_invalid_pluralization_data do |exception|
       assert_match '1', exception.message
-      assert_match '{:other=>"bar"}', exception.message
+      assert_match %|#{{:other=>"bar"}}|, exception.message
       assert_match 'one', exception.message
     end
   end
@@ -58,7 +58,7 @@ def test_invalid_locale_stores_locale
 
   test "MissingInterpolationArgument message contains the missing and given arguments" do
     force_missing_interpolation_argument do |exception|
-      assert_equal 'missing interpolation argument :bar in "%{bar}" ({:baz=>"baz"} given)', exception.message
+      assert_equal %|missing interpolation argument :bar in "%{bar}" (#{{:baz=>"baz"}.to_s} given)|, exception.message
     end
   end
 
diff --git a/test/i18n/interpolate_test.rb b/test/i18n/interpolate_test.rb
index 2d54090f..e9ef2c13 100644
--- a/test/i18n/interpolate_test.rb
+++ b/test/i18n/interpolate_test.rb
@@ -91,7 +91,7 @@ def teardown
   end
 
   test "String interpolation can use custom missing interpolation handler" do
-    assert_equal %|Masao missing key is last, values are {:first=>"Masao"}, given string is '%{first} %{last}'|,
+    assert_equal %|Masao missing key is last, values are #{{:first=>"Masao"}.to_s}, given string is '%{first} %{last}'|,
       I18n.interpolate("%{first} %{last}", :first => 'Masao')
   end
 end
diff --git a/test/locale/fallbacks_test.rb b/test/locale/fallbacks_test.rb
index c7218f38..d86041d2 100644
--- a/test/locale/fallbacks_test.rb
+++ b/test/locale/fallbacks_test.rb
@@ -179,6 +179,6 @@ def setup
   end
 
   test "#inspect" do
-    assert_equal('#<I18n::Locale::Fallbacks @map={:"de-AT"=>[:"de-DE"]} @defaults=[:"en-US", :en]>', @fallbacks.inspect)
+    assert_equal(%|#<I18n::Locale::Fallbacks @map=#{{:"de-AT"=>[:"de-DE"]}} @defaults=[:"en-US", :en]>|, @fallbacks.inspect)
   end
 end