diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index f232d7b..9c4e456 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -12,5 +12,21 @@ permissions:
   contents: read
 
 jobs:
-  Shared:
-    uses: fog/.github/.github/workflows/ci.yml@v1.4.0
+  test:
+
+    runs-on: ubuntu-latest
+
+    strategy:
+      matrix:
+        ruby-version: ['3.0', '3.1', '3.2', '3.3', 'head']
+    continue-on-error: ${{ matrix.ruby-version == 'head' }}
+
+    steps:
+    - uses: actions/checkout@v4
+    - name: Set up Ruby
+      uses: ruby/setup-ruby@v1
+      with:
+        ruby-version: ${{ matrix.ruby-version }}
+        bundler-cache: true # runs 'bundle install' and caches installed gems automatically
+    - name: Run tests
+      run: bundle exec rake RUBYOPT="--enable-frozen-string-literal"
diff --git a/lib/fog/compute.rb b/lib/fog/compute.rb
index 330cc89..62d1620 100644
--- a/lib/fog/compute.rb
+++ b/lib/fog/compute.rb
@@ -29,7 +29,7 @@ def self.new(orig_attributes)
           Fog::Compute::DigitalOcean.new(attributes)
         end
       else
-        super(orig_attributes)
+        super
       end
     end
 
diff --git a/lib/fog/core.rb b/lib/fog/core.rb
index 230f047..3e86ee2 100644
--- a/lib/fog/core.rb
+++ b/lib/fog/core.rb
@@ -1,5 +1,4 @@
 # external core dependencies
-require "base64"
 require "cgi"
 require "uri"
 require "excon"
diff --git a/lib/fog/core/mock.rb b/lib/fog/core/mock.rb
index 9352c1a..33696d1 100644
--- a/lib/fog/core/mock.rb
+++ b/lib/fog/core/mock.rb
@@ -81,7 +81,7 @@ def self.random_letters_and_numbers(length)
     end
 
     def self.random_selection(characters, length)
-      selection = ""
+      selection = +""
       length.times do
         position = rand(characters.length)
         selection << characters[position..position]
diff --git a/lib/fog/core/provider.rb b/lib/fog/core/provider.rb
index ccc0d90..04f95fa 100644
--- a/lib/fog/core/provider.rb
+++ b/lib/fog/core/provider.rb
@@ -18,7 +18,7 @@ def extended(base)
       private
 
       def underscore_name(string)
-        string.gsub(/::/, "/")
+        string.gsub("::", "/")
               .gsub(/([A-Z]+)([A-Z][a-z])/,'\1_\2')
               .gsub(/([a-z\d])([A-Z])/,'\1_\2')
               .tr("-", "_")
diff --git a/lib/fog/core/service.rb b/lib/fog/core/service.rb
index 637f8d4..3188453 100644
--- a/lib/fog/core/service.rb
+++ b/lib/fog/core/service.rb
@@ -212,7 +212,7 @@ def secrets(*args)
           @secrets ||= []
         else
           args.reduce(secrets) do |secrets, secret|
-            secrets << "@#{secret}".to_sym
+            secrets << :"@#{secret}"
           end
         end
       end
diff --git a/lib/fog/formatador.rb b/lib/fog/formatador.rb
index bc85aea..75c53a6 100644
--- a/lib/fog/formatador.rb
+++ b/lib/fog/formatador.rb
@@ -10,7 +10,7 @@ def self.formatador
     end
 
     def self.format(object, opts = { include_nested: true })
-      string = init_string(object)
+      string = +init_string(object)
       indent { string << object_string(object, opts) }
       string << "#{indentation}>"
     end
@@ -48,7 +48,7 @@ def self.init_string(object)
     end
 
     def self.object_string(object, opts)
-      string = attribute_string(object).to_s
+      string = +attribute_string(object).to_s
       string << nested_objects_string(object).to_s if opts[:include_nested]
       string
     end
@@ -68,7 +68,7 @@ def self.nested_objects_string(object)
       return nested if object.respond_to?(:empty) and object.empty?
       return nested unless object.is_a?(Enumerable)
 
-      nested = "#{indentation}[\n"
+      nested = +"#{indentation}[\n"
       indent { nested << indentation + inspect_object(object) }
       nested << "#{indentation}\n#{indentation}]\n"
     end
diff --git a/lib/fog/storage.rb b/lib/fog/storage.rb
index f721def..dd0ca7b 100644
--- a/lib/fog/storage.rb
+++ b/lib/fog/storage.rb
@@ -59,7 +59,6 @@ def self.parse_data(data)
         headers: {
           "Content-Length" => get_body_size(data),
           "Content-Type" => get_content_type(data)
-          # "Content-MD5" => Base64.encode64(Digest::MD5.digest(metadata[:body])).strip
         }
       }
     end
diff --git a/lib/tasks/test_task.rb b/lib/tasks/test_task.rb
index e42a9d4..a904871 100644
--- a/lib/tasks/test_task.rb
+++ b/lib/tasks/test_task.rb
@@ -22,10 +22,9 @@ def initialize
       def tests(mocked)
         Fog::Formatador.display_line
         start = Time.now.to_i
-        threads = []
         Thread.main[:results] = []
-        Fog.providers.each do |key, value|
-          threads << Thread.new do
+        threads = Fog.providers.map do |key, value|
+          Thread.new do
             Thread.main[:results] << {
               provider: value,
               success: sh("export FOG_MOCK=#{mocked} && bundle exec shindont +#{key}")
diff --git a/spec/core/collection_spec.rb b/spec/core/collection_spec.rb
index acea928..a972174 100644
--- a/spec/core/collection_spec.rb
+++ b/spec/core/collection_spec.rb
@@ -2,7 +2,7 @@
 require "securerandom"
 
 class FogTestModelForCollection < Fog::Model
-  identity  :id
+  identity :id
 end
 
 class FogTestCollection < Fog::Collection
diff --git a/spec/formatador_spec.rb b/spec/formatador_spec.rb
index 90a77db..e645832 100644
--- a/spec/formatador_spec.rb
+++ b/spec/formatador_spec.rb
@@ -42,7 +42,7 @@ def all
     end
 
     it "returns formatted representation" do
-      Fog::Formatador.format(@collection).must_equal @expected
+      _(Fog::Formatador.format(@collection)).must_equal @expected
     end
   end
 
@@ -65,7 +65,7 @@ def all
     end
 
     it "returns formatted representation" do
-      Fog::Formatador.format(@collection).must_equal @expected
+      _(Fog::Formatador.format(@collection)).must_equal @expected
     end
   end
 
@@ -90,7 +90,7 @@ def all
       EOS
 
       opts = { include_nested: false }
-      Fog::Formatador.format(@collection, opts).must_equal @expected
+      _(Fog::Formatador.format(@collection, opts)).must_equal @expected
     end
   end
 
@@ -105,7 +105,7 @@ def all
     end
 
     it "returns formatted representation" do
-      Fog::Formatador.format(@subject).must_equal @expected
+      _(Fog::Formatador.format(@subject)).must_equal @expected
     end
   end
 
@@ -148,7 +148,7 @@ def all
     end
 
     it "returns formatted representation" do
-      Fog::Formatador.format(@collection).must_equal @expected
+      _(Fog::Formatador.format(@collection)).must_equal @expected
     end
   end
 end
diff --git a/spec/service_spec.rb b/spec/service_spec.rb
index d09f278..18b3668 100644
--- a/spec/service_spec.rb
+++ b/spec/service_spec.rb
@@ -88,7 +88,7 @@ class Mock; def initialize(*_args); end; end
     it "returns the real service" do
       Fog.stub :mocking?, false do
         service = TestService.new(generic_api_key: "abc")
-        service.must_be_instance_of TestService::Real
+        _(service).must_be_instance_of TestService::Real
       end
     end
 
@@ -115,7 +115,7 @@ class Mock; def initialize(*_args); end; end
     it "returns mocked service" do
       Fog.stub :mocking?, true do
         service = TestService.new(generic_api_key: "abc")
-        service.must_be_instance_of TestService::Mock
+        _(service).must_be_instance_of TestService::Mock
       end
     end