diff --git a/sentry-ruby/lib/sentry/configuration.rb b/sentry-ruby/lib/sentry/configuration.rb
index ec582bdd6..424ff479e 100644
--- a/sentry-ruby/lib/sentry/configuration.rb
+++ b/sentry-ruby/lib/sentry/configuration.rb
@@ -405,7 +405,7 @@ def valid?
     def sample_allowed?
       return true if sample_rate == 1.0
 
-      if Random::DEFAULT.rand >= sample_rate
+      if Random.rand >= sample_rate
         @errors << "Excluded by random sample"
         false
       else
diff --git a/sentry-ruby/lib/sentry/core_ext/object/deep_dup.rb b/sentry-ruby/lib/sentry/core_ext/object/deep_dup.rb
index cb4ca46ba..1c4adb53f 100644
--- a/sentry-ruby/lib/sentry/core_ext/object/deep_dup.rb
+++ b/sentry-ruby/lib/sentry/core_ext/object/deep_dup.rb
@@ -20,6 +20,7 @@ def deep_dup
 end
 
 class Array
+  undef_method :deep_dup if method_defined?(:deep_dup)
   # Returns a deep copy of array.
   #
   #   array = [1, [2, 3]]
diff --git a/sentry-ruby/lib/sentry/core_ext/object/duplicable.rb b/sentry-ruby/lib/sentry/core_ext/object/duplicable.rb
index b70adb5bc..722adf04a 100644
--- a/sentry-ruby/lib/sentry/core_ext/object/duplicable.rb
+++ b/sentry-ruby/lib/sentry/core_ext/object/duplicable.rb
@@ -115,6 +115,7 @@ def duplicable?
 end
 
 class Method
+  undef_method :duplicable? if method_defined?(:duplicable?)
   # Methods are not duplicable:
   #
   #  method(:puts).duplicable? # => false
diff --git a/sentry-ruby/lib/sentry/transport/configuration.rb b/sentry-ruby/lib/sentry/transport/configuration.rb
index f630068f5..2ab6d7aad 100644
--- a/sentry-ruby/lib/sentry/transport/configuration.rb
+++ b/sentry-ruby/lib/sentry/transport/configuration.rb
@@ -2,7 +2,8 @@ module Sentry
   class Transport
     class Configuration
       attr_accessor :timeout, :open_timeout, :proxy, :ssl, :ssl_ca_file, :ssl_verification, :http_adapter, :faraday_builder,
-        :transport_class, :encoding
+        :encoding
+      attr_reader :transport_class
 
       def initialize
         @ssl_verification = true
diff --git a/sentry-ruby/spec/sentry/configuration_spec.rb b/sentry-ruby/spec/sentry/configuration_spec.rb
index 858ae0152..53ec68455 100644
--- a/sentry-ruby/spec/sentry/configuration_spec.rb
+++ b/sentry-ruby/spec/sentry/configuration_spec.rb
@@ -195,13 +195,13 @@
     end
 
     it 'captured_allowed false when sampled' do
-      allow(Random::DEFAULT).to receive(:rand).and_return(0.76)
+      allow(Random).to receive(:rand).and_return(0.76)
       expect(subject.sending_allowed?).to eq(false)
       expect(subject.errors).to eq(["Excluded by random sample"])
     end
 
     it 'captured_allowed true when not sampled' do
-      allow(Random::DEFAULT).to receive(:rand).and_return(0.74)
+      allow(Random).to receive(:rand).and_return(0.74)
       expect(subject.sending_allowed?).to eq(true)
     end
   end
diff --git a/sentry-ruby/spec/sentry/interfaces/request_interface_spec.rb b/sentry-ruby/spec/sentry/interfaces/request_interface_spec.rb
index 21c48dd65..801e1ca2f 100644
--- a/sentry-ruby/spec/sentry/interfaces/request_interface_spec.rb
+++ b/sentry-ruby/spec/sentry/interfaces/request_interface_spec.rb
@@ -66,7 +66,7 @@
       it 'does not call #to_s for unnecessary env variables' do
         expect(mock).not_to receive(:to_s)
 
-        interface = described_class.build(env: env)
+        described_class.build(env: env)
       end
     end
   end
@@ -133,7 +133,7 @@ def to_s
 
       new_env = env.merge("HTTP_FOO" => "BAR", "rails_object" => obj)
 
-      expect { interface = described_class.build(env: new_env) }.to_not raise_error
+      expect { described_class.build(env: new_env) }.to_not raise_error
     end
   end
 
diff --git a/sentry-ruby/spec/sentry/net/http_spec.rb b/sentry-ruby/spec/sentry/net/http_spec.rb
index 5b2007f86..89756ffcd 100644
--- a/sentry-ruby/spec/sentry/net/http_spec.rb
+++ b/sentry-ruby/spec/sentry/net/http_spec.rb
@@ -10,15 +10,7 @@
     ::Logger.new(string_io)
   end
 
-  original_buffered_io = Net::BufferedIO
-
-  before(:all) do
-    Net.send(:const_set, :BufferedIO, Net::WebMockNetBufferedIO)
-  end
-
-  after(:all) do
-    Net.send(:const_set, :BufferedIO, original_buffered_io)
-  end
+  before { stub_const('Net::BufferedIO', Net::WebMockNetBufferedIO) }
 
   class FakeSocket < StringIO
     def setsockopt(*args); end
diff --git a/sentry-ruby/spec/sentry/transport_spec.rb b/sentry-ruby/spec/sentry/transport_spec.rb
index dc89d4588..a318487f3 100644
--- a/sentry-ruby/spec/sentry/transport_spec.rb
+++ b/sentry-ruby/spec/sentry/transport_spec.rb
@@ -87,7 +87,7 @@
       before do
         configuration.logger = Logger.new(string_io)
         configuration.sample_rate = 0.5
-        allow(Random::DEFAULT).to receive(:rand).and_return(0.6)
+        allow(Random).to receive(:rand).and_return(0.6)
       end
 
       it "logs correct message" do