diff --git a/.rubocop.yml b/.rubocop.yml
index 241a8c9d18..20dac8c1d3 100644
--- a/.rubocop.yml
+++ b/.rubocop.yml
@@ -53,6 +53,12 @@ Naming/VariableNumber:
     - 'lib/facter/resolvers/windows/ffi/networking_ffi.rb'
     - 'lib/facter/util/facts/windows_release_finder.rb'
 
+RSpec/MultipleMemoizedHelpers:
+  Enabled: false
+
+RSpec/StubbedMock:
+  Enabled: false
+
 Style/IfUnlessModifier:
   Enabled: false
 
@@ -67,3 +73,43 @@ Style/GlobalStdStream:
     - 'lib/facter/framework/logging/logger.rb'
     - 'spec/framework/core/fact/internal/internal_fact_manager_spec.rb'
     - 'spec/framework/logging/logger_spec.rb'
+
+RSpec/DescribedClass:
+  EnforcedStyle: explicit
+
+RSpec/ExampleLength:
+  Enabled: false
+
+# It is sometimes better to expect().to receive().and_return
+# or to receive different messages.
+RSpec/MessageSpies:
+  Enabled: false
+
+RSpec/MultipleExpectations:
+  Max: 3
+
+RSpec/MultipleMemoizedHelpers:
+  Enabled: false
+
+RSpec/NestedGroups:
+  Enabled: 6
+
+RSpec/SubjectStub:
+  Exclude:
+    - 'spec/custom_facts/core/aggregate_spec.rb'
+    - 'spec/custom_facts/core/resolvable_spec.rb'
+    - 'spec/custom_facts/util/fact_spec.rb'
+    - 'spec/custom_facts/util/resolution_spec.rb'
+
+# Prefer instance_double/instance_spy over double/spy because only methods
+# defined on the underlying object can be stubbed. FFI and some Windows
+# code can't be verified because of the way we fake out those classes.
+RSpec/VerifiedDoubles:
+  Enabled: true
+  Exclude:
+    - 'spec/custom_facts/**/*'
+    - 'spec/facter/resolvers/aix/hardware_spec.rb'
+    - 'spec/facter/resolvers/*/ffi_helper_spec.rb'
+    - 'spec/facter/resolvers/windows/*'
+    - 'spec/facter/util/windows/network_utils_spec.rb'
+    - 'spec/facter/util/windows/win32ole_spec.rb'
diff --git a/.rubocop_todo.yml b/.rubocop_todo.yml
index 3239cc990d..4cc40fa416 100644
--- a/.rubocop_todo.yml
+++ b/.rubocop_todo.yml
@@ -6,95 +6,12 @@
 # Note that changes in the inspected code, or installation of new
 # versions of RuboCop, may require this file to be generated again.
 
-# Offense count: 3
-# This cop supports safe autocorrection (--autocorrect).
-Performance/RegexpMatch:
-  Exclude:
-    - 'install.rb'
-
-# Offense count: 1490
-# This cop supports unsafe autocorrection (--autocorrect-all).
-# Configuration parameters: SkipBlocks, EnforcedStyle.
-# SupportedStyles: described_class, explicit
-RSpec/DescribedClass:
-  Enabled: false
-
-# Offense count: 192
-# Configuration parameters: CountAsOne.
-RSpec/ExampleLength:
-  Max: 34
-
-# Offense count: 1
-# This cop supports safe autocorrection (--autocorrect).
-# Configuration parameters: CustomTransform, IgnoredWords, DisallowedExamples.
-# DisallowedExamples: works
-RSpec/ExampleWording:
-  Exclude:
-    - 'spec/custom_facts/core/execution/windows_spec.rb'
-
 # Offense count: 70
 # Configuration parameters: Include, CustomTransform, IgnoreMethods, SpecSuffixOnly.
 # Include: **/*_spec*rb*, **/spec/**/*
 RSpec/FilePath:
   Enabled: false
 
-# Offense count: 15
-# Configuration parameters: AssignmentOnly.
-RSpec/InstanceVariable:
-  Exclude:
-    - 'spec/custom_facts/core/execution/fact_manager_spec.rb'
-    - 'spec/custom_facts/util/collection_spec.rb'
-    - 'spec/custom_facts/util/confine_spec.rb'
-
-# Offense count: 8
-RSpec/LeakyConstantDeclaration:
-  Exclude:
-    - 'spec/custom_facts/core/resolvable_spec.rb'
-    - 'spec/custom_facts/core/suitable_spec.rb'
-    - 'spec/custom_facts/util/collection_spec.rb'
-    - 'spec/facter/resolvers/macosx/mountpoints_spec.rb'
-    - 'spec/facter/util/windows/network_utils_spec.rb'
-
-# Offense count: 51
-# Configuration parameters: EnforcedStyle.
-# SupportedStyles: have_received, receive
-RSpec/MessageSpies:
-  Enabled: false
-
-# Offense count: 13
-RSpec/MultipleExpectations:
-  Max: 3
-
-# Offense count: 166
-# Configuration parameters: AllowSubject.
-RSpec/MultipleMemoizedHelpers:
-  Max: 16
-
-# Offense count: 241
-# Configuration parameters: AllowedGroups.
-RSpec/NestedGroups:
-  Max: 6
-
-# Offense count: 3
-RSpec/StubbedMock:
-  Exclude:
-    - 'spec/custom_facts/core/execution/fact_manager_spec.rb'
-    - 'spec/custom_facts/util/confine_spec.rb'
-    - 'spec/custom_facts/util/parser_spec.rb'
-
-# Offense count: 6
-RSpec/SubjectStub:
-  Exclude:
-    - 'spec/custom_facts/core/aggregate_spec.rb'
-    - 'spec/custom_facts/core/resolvable_spec.rb'
-    - 'spec/custom_facts/util/fact_spec.rb'
-    - 'spec/custom_facts/util/resolution_spec.rb'
-
-# Offense count: 114
-# Configuration parameters: IgnoreNameless, IgnoreSymbolicNames.
-RSpec/VerifiedDoubles:
-  Enabled: false
-
 # Need to remove logger class variables
 Style/ClassVars:
   Exclude:
diff --git a/install.rb b/install.rb
index 730b17e1b0..12a8878632 100755
--- a/install.rb
+++ b/install.rb
@@ -40,7 +40,7 @@ class Installer
 
   # Returns true if OS is windows (copied from facter/util/config.rb)
   def windows?
-    (defined?(RbConfig) ? RbConfig : Config)::CONFIG['host_os'] =~ /mswin|win32|dos|mingw|cygwin/i
+    (defined?(RbConfig) ? RbConfig : Config)::CONFIG['host_os'].match?(/mswin|win32|dos|mingw|cygwin/i)
   end
 
   def glob(list)
@@ -153,7 +153,7 @@ def prepare_installation
     # /System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/bin
     # which is not generally where people expect executables to be installed
     # These settings are appropriate defaults for all OS X versions.
-    RbConfig::CONFIG['bindir'] = '/usr/bin' if RUBY_PLATFORM =~ /^universal-darwin[\d.]+$/
+    RbConfig::CONFIG['bindir'] = '/usr/bin' if RUBY_PLATFORM.match?(/^universal-darwin[\d.]+$/)
 
     # if InstallOptions.configdir
     #   configdir = InstallOptions.configdir
@@ -173,10 +173,10 @@ def prepare_installation
     else
       sitelibdir = RbConfig::CONFIG['sitelibdir']
       if sitelibdir.nil?
-        sitelibdir = $LOAD_PATH.find { |x| x =~ /site_ruby/ }
+        sitelibdir = $LOAD_PATH.find { |x| x.match?(/site_ruby/) }
         if sitelibdir.nil?
           sitelibdir = File.join(libdir, 'site_ruby')
-        elsif sitelibdir !~ Regexp.quote(version)
+        elsif !sitelibdir.match?(Regexp.quote(version))
           sitelibdir = File.join(sitelibdir, version)
         end
       end
@@ -232,7 +232,7 @@ def install_binfile(from, op_file, target)
       File.open(tmp_file.path, 'w') do |op|
         op.puts "#!#{ruby}"
         contents = ip.readlines
-        contents.shift if contents[0] =~ /^#!/
+        contents.shift if contents[0].match?(/^#!/)
         op.write contents.join
       end
     end
diff --git a/spec/custom_facts/core/execution/fact_manager_spec.rb b/spec/custom_facts/core/execution/fact_manager_spec.rb
index 2db211dc5c..1a6ce8f7f6 100644
--- a/spec/custom_facts/core/execution/fact_manager_spec.rb
+++ b/spec/custom_facts/core/execution/fact_manager_spec.rb
@@ -4,6 +4,8 @@
   subject(:executor) { Facter::Core::Execution::Posix.new }
 
   describe '#with_env' do
+    let(:sentinel_var) { :resolution_test_foo.to_s }
+
     it "executes the caller's block with the specified env vars" do
       test_env = { 'LANG' => 'C', 'LC_ALL' => 'C', 'FOO' => 'BAR' }
       executor.with_env test_env do
@@ -56,23 +58,21 @@
     end
 
     it "is not affected by a 'return' statement in the yield block" do
-      @sentinel_var = :resolution_test_foo.to_s
-
       # the intent of this test case is to test a yield block that contains a return statement.  However, it's illegal
       # to use a return statement outside of a method, so we need to create one here to give scope to the 'return'
       def handy_method
-        ENV[@sentinel_var] = 'foo'
-        new_env = { @sentinel_var => 'bar' }
+        ENV[sentinel_var] = 'foo'
+        new_env = { sentinel_var => 'bar' }
 
         executor.with_env new_env do
-          ENV[@sentinel_var] = 'bar'
+          ENV[sentinel_var] = 'bar'
           return
         end
       end
 
       handy_method
 
-      expect(ENV[@sentinel_var]).to eq 'foo'
+      expect(ENV[sentinel_var]).to eq 'foo'
     end
   end
 
diff --git a/spec/custom_facts/core/execution/windows_spec.rb b/spec/custom_facts/core/execution/windows_spec.rb
index 275702b243..13f7d6f04c 100644
--- a/spec/custom_facts/core/execution/windows_spec.rb
+++ b/spec/custom_facts/core/execution/windows_spec.rb
@@ -82,7 +82,7 @@
         expect(executor.which('foo.exe')).to eq 'C:\Windows\foo.exe'
       end
 
-      it "won't check all paths if one is executable" do
+      it 'does not check all paths if one is executable' do
         allow(File).to receive(:executable?).with('C:\Windows\system32\foo.exe').and_return false
         allow(File).to receive(:executable?).with('C:\Windows\foo.exe').and_return true
 
diff --git a/spec/custom_facts/util/collection_spec.rb b/spec/custom_facts/util/collection_spec.rb
index 7638a132cc..6ee3e0dab2 100755
--- a/spec/custom_facts/util/collection_spec.rb
+++ b/spec/custom_facts/util/collection_spec.rb
@@ -125,20 +125,21 @@ def load(collection)
   end
 
   describe 'when retrieving facts' do
-    before do
-      @fact = collection.add('YayNess')
-    end
+    let(:fact) { collection.add('YayNess') }
+
+    # initialize
+    before { fact }
 
     it 'returns the fact instance specified by the name' do
-      expect(collection.fact('YayNess')).to equal(@fact)
+      expect(collection.fact('YayNess')).to equal(fact)
     end
 
     it 'is case-insensitive' do
-      expect(collection.fact('yayness')).to equal(@fact)
+      expect(collection.fact('yayness')).to equal(fact)
     end
 
     it 'treats strings and symbols equivalently' do
-      expect(collection.fact(:yayness)).to equal(@fact)
+      expect(collection.fact(:yayness)).to equal(fact)
     end
 
     it 'uses its loader to try to load the fact if no fact can be found' do
diff --git a/spec/custom_facts/util/confine_spec.rb b/spec/custom_facts/util/confine_spec.rb
index a7e80e2c31..0b1bdf628e 100755
--- a/spec/custom_facts/util/confine_spec.rb
+++ b/spec/custom_facts/util/confine_spec.rb
@@ -27,14 +27,15 @@
   end
 
   describe 'when evaluating' do
+    let(:fact) { double 'fact' }
+
     def confined(fact_value, *confines)
-      allow(@fact).to receive(:value).and_return fact_value
+      allow(fact).to receive(:value).and_return fact_value
       LegacyFacter::Util::Confine.new('yay', *confines).true?
     end
 
     before do
-      @fact = double 'fact'
-      allow(Facter).to receive(:[]).and_return @fact
+      allow(Facter).to receive(:[]).and_return fact
     end
 
     it 'returns false if the fact does not exist' do
@@ -44,9 +45,9 @@ def confined(fact_value, *confines)
     end
 
     it 'uses the returned fact to get the value' do
-      allow(Facter).to receive(:[]).with('yay').and_return @fact
+      allow(Facter).to receive(:[]).with('yay').and_return fact
 
-      expect(@fact).to receive(:value).and_return nil
+      expect(fact).to receive(:value).and_return nil
 
       LegacyFacter::Util::Confine.new('yay', 'test').true?
     end
@@ -120,13 +121,13 @@ def confined(fact_value, *confines)
     end
 
     it 'accepts and evaluate a block argument against the fact' do
-      allow(@fact).to receive(:value).and_return 'foo'
+      allow(fact).to receive(:value).and_return 'foo'
       confine = LegacyFacter::Util::Confine.new(:yay) { |f| f == 'foo' }
       expect(confine.true?).to be true
     end
 
     it 'returns false if the block raises a StandardError when checking a fact' do
-      allow(@fact).to receive(:value).and_return 'foo'
+      allow(fact).to receive(:value).and_return 'foo'
       confine = LegacyFacter::Util::Confine.new(:yay) { |_f| raise StandardError }
       expect(confine.true?).to be false
     end
diff --git a/spec/facter/facts/macosx/memory/swap/capacity_spec.rb b/spec/facter/facts/macosx/memory/swap/capacity_spec.rb
index 2db9dd22a7..724d18ee02 100644
--- a/spec/facter/facts/macosx/memory/swap/capacity_spec.rb
+++ b/spec/facter/facts/macosx/memory/swap/capacity_spec.rb
@@ -3,7 +3,7 @@
 describe Facts::Macosx::Memory::Swap::Capacity do
   describe '#call_the_resolver' do
     it 'returns a fact' do
-      expected_fact = double(Facter::ResolvedFact, name: 'memory.swap.capacity', value: 1024)
+      expected_fact = instance_double(Facter::ResolvedFact, name: 'memory.swap.capacity', value: 1024)
 
       allow(Facter::Resolvers::Macosx::SwapMemory).to receive(:resolve).with(:capacity).and_return(1024)
       allow(Facter::ResolvedFact).to receive(:new).with('memory.swap.capacity', 1024).and_return(expected_fact)
diff --git a/spec/facter/facts/macosx/memory/swap/used_bytes_spec.rb b/spec/facter/facts/macosx/memory/swap/used_bytes_spec.rb
index 26578d2a56..5ec94c5cd6 100644
--- a/spec/facter/facts/macosx/memory/swap/used_bytes_spec.rb
+++ b/spec/facter/facts/macosx/memory/swap/used_bytes_spec.rb
@@ -3,7 +3,7 @@
 describe Facts::Macosx::Memory::Swap::UsedBytes do
   describe '#call_the_resolver' do
     it 'returns a fact' do
-      expected_fact = double(Facter::ResolvedFact, name: 'memory.swap.used_bytes', value: 1024)
+      expected_fact = instance_double(Facter::ResolvedFact, name: 'memory.swap.used_bytes', value: 1024)
 
       allow(Facter::Resolvers::Macosx::SwapMemory).to receive(:resolve).with(:used_bytes).and_return(1024)
       allow(Facter::ResolvedFact).to receive(:new).with('memory.swap.used_bytes', 1024).and_return(expected_fact)
diff --git a/spec/facter/facts/macosx/memory/system/capacity_spec.rb b/spec/facter/facts/macosx/memory/system/capacity_spec.rb
index 4aeefb370d..ad614e2d08 100644
--- a/spec/facter/facts/macosx/memory/system/capacity_spec.rb
+++ b/spec/facter/facts/macosx/memory/system/capacity_spec.rb
@@ -3,7 +3,7 @@
 describe Facts::Macosx::Memory::System::Capacity do
   describe '#call_the_resolver' do
     it 'returns a fact' do
-      expected_fact = double(Facter::ResolvedFact, name: 'memory.system.capacity', value: '15.53%')
+      expected_fact = instance_double(Facter::ResolvedFact, name: 'memory.system.capacity', value: '15.53%')
 
       allow(Facter::Resolvers::Macosx::SystemMemory).to receive(:resolve).with(:capacity).and_return('15.53%')
       allow(Facter::ResolvedFact).to receive(:new).with('memory.system.capacity', '15.53%').and_return(expected_fact)
diff --git a/spec/facter/facts/macosx/memory/system/used_bytes_spec.rb b/spec/facter/facts/macosx/memory/system/used_bytes_spec.rb
index ca6d05682f..a41dbe6928 100644
--- a/spec/facter/facts/macosx/memory/system/used_bytes_spec.rb
+++ b/spec/facter/facts/macosx/memory/system/used_bytes_spec.rb
@@ -3,7 +3,7 @@
 describe Facts::Macosx::Memory::System::UsedBytes do
   describe '#call_the_resolver' do
     it 'returns a fact' do
-      expected_fact = double(Facter::ResolvedFact, name: 'memory.system.used_bytes', value: 1024)
+      expected_fact = instance_double(Facter::ResolvedFact, name: 'memory.system.used_bytes', value: 1024)
 
       allow(Facter::Resolvers::Macosx::SystemMemory).to receive(:resolve).with(:used_bytes).and_return(1024)
       allow(Facter::ResolvedFact).to receive(:new).with('memory.system.used_bytes', 1024).and_return(expected_fact)
diff --git a/spec/facter/facts/windows/dmi/product/serial_number_spec.rb b/spec/facter/facts/windows/dmi/product/serial_number_spec.rb
index f713ada40f..00f06ec246 100644
--- a/spec/facter/facts/windows/dmi/product/serial_number_spec.rb
+++ b/spec/facter/facts/windows/dmi/product/serial_number_spec.rb
@@ -5,8 +5,8 @@
     subject(:fact) { Facts::Windows::Dmi::Product::SerialNumber.new }
 
     let(:value) { 'VMware-42 1a 0d 03 0a b7 98 28-78 98 5e 85 a0 ad 18 47' }
-    let(:expected_resolved_fact) { double(Facter::ResolvedFact, name: 'dmi.product.serial_number', value: value) }
-    let(:resolved_legacy_fact) { double(Facter::ResolvedFact, name: 'serialnumber', value: value, type: :legacy) }
+    let(:expected_resolved_fact) { instance_double(Facter::ResolvedFact, name: 'dmi.product.serial_number', value: value) }
+    let(:resolved_legacy_fact) { instance_double(Facter::ResolvedFact, name: 'serialnumber', value: value, type: :legacy) }
 
     before do
       allow(Facter::Resolvers::DMIBios).to receive(:resolve).with(:serial_number).and_return(value)
diff --git a/spec/facter/facts/windows/hypervisors/hyperv_spec.rb b/spec/facter/facts/windows/hypervisors/hyperv_spec.rb
index ac53f7a813..87a44520fb 100644
--- a/spec/facter/facts/windows/hypervisors/hyperv_spec.rb
+++ b/spec/facter/facts/windows/hypervisors/hyperv_spec.rb
@@ -4,7 +4,7 @@
   describe '#call_the_resolver' do
     context 'when is not HyperV hypervisor' do
       it 'returns nil' do
-        expected_fact = double(Facter::ResolvedFact, name: 'hypervisors.hyperv', value: nil)
+        expected_fact = instance_double(Facter::ResolvedFact, name: 'hypervisors.hyperv', value: nil)
         allow(Facter::Resolvers::Windows::Virtualization).to receive(:resolve).with(:virtual).and_return('value')
         allow(Facter::Resolvers::DMIBios).to receive(:resolve).with(:manufacturer).and_return('value')
         allow(Facter::ResolvedFact).to receive(:new).with('hypervisors.hyperv', nil).and_return(expected_fact)
@@ -16,7 +16,7 @@
 
     context 'when is HyperV hypervisor and CpuidSource resolver returns the required output' do
       it 'returns a fact' do
-        expected_fact = double(Facter::ResolvedFact, name: 'hypervisors.hyperv', value: {})
+        expected_fact = instance_double(Facter::ResolvedFact, name: 'hypervisors.hyperv', value: {})
         allow(Facter::Resolvers::Windows::Virtualization).to receive(:resolve).with(:virtual).and_return('hyperv')
         allow(Facter::ResolvedFact).to receive(:new).with('hypervisors.hyperv', {}).and_return(expected_fact)
 
@@ -27,7 +27,7 @@
 
     context 'when is HyperV hypervisor and DmiBios resolver returns the required output' do
       it 'returns a fact' do
-        expected_fact = double(Facter::ResolvedFact, name: 'hypervisors.hyperv', value: {})
+        expected_fact = instance_double(Facter::ResolvedFact, name: 'hypervisors.hyperv', value: {})
         allow(Facter::Resolvers::Windows::Virtualization).to receive(:resolve).with(:virtual).and_return('value')
         allow(Facter::Resolvers::DMIBios).to receive(:resolve).with(:manufacturer).and_return('Microsoft Enterprise')
         allow(Facter::ResolvedFact).to receive(:new).with('hypervisors.hyperv', {}).and_return(expected_fact)
diff --git a/spec/facter/facts/windows/hypervisors/kvm_spec.rb b/spec/facter/facts/windows/hypervisors/kvm_spec.rb
index 2cb0ba980e..bf00e23958 100644
--- a/spec/facter/facts/windows/hypervisors/kvm_spec.rb
+++ b/spec/facter/facts/windows/hypervisors/kvm_spec.rb
@@ -4,7 +4,7 @@
   describe '#call_the_resolver' do
     context 'when is not kvm hypervisor' do
       it 'returns nil' do
-        expected_fact = double(Facter::ResolvedFact, name: 'hypervisors.kvm', value: nil)
+        expected_fact = instance_double(Facter::ResolvedFact, name: 'hypervisors.kvm', value: nil)
         allow(Facter::Resolvers::Windows::Virtualization).to receive(:resolve).with(:virtual).and_return('value')
         allow(Facter::Resolvers::NetKVM).to receive(:resolve).with(:kvm).and_return(false)
         allow(Facter::Resolvers::DMIComputerSystem).to receive(:resolve).with(:name).and_return('value')
@@ -17,7 +17,7 @@
 
     context 'when is kvm hypervisor but product name is parallels' do
       it 'returns a fact' do
-        expected_fact = double(Facter::ResolvedFact, name: 'hypervisors.kvm', value: nil)
+        expected_fact = instance_double(Facter::ResolvedFact, name: 'hypervisors.kvm', value: nil)
         allow(Facter::Resolvers::Windows::Virtualization).to receive(:resolve).with(:virtual).and_return('kvm')
         allow(Facter::Resolvers::DMIComputerSystem).to receive(:resolve).with(:name).and_return('Parallels')
         allow(Facter::ResolvedFact).to receive(:new).with('hypervisors.kvm', nil).and_return(expected_fact)
@@ -29,7 +29,7 @@
 
     context 'when is kvm hypervisor and openstack' do
       it 'returns a fact' do
-        expected_fact = double(Facter::ResolvedFact, name: 'hypervisors.kvm', value: { openstack: true })
+        expected_fact = instance_double(Facter::ResolvedFact, name: 'hypervisors.kvm', value: { openstack: true })
         allow(Facter::Resolvers::Windows::Virtualization).to receive(:resolve).with(:virtual).and_return('kvm')
         allow(Facter::Resolvers::DMIComputerSystem).to receive(:resolve).with(:name).and_return('OpenStack')
         allow(Facter::Resolvers::DMIBios).to receive(:resolve).with(:manufacturer).and_return('value')
@@ -44,7 +44,7 @@
 
     context 'when is kvm hypervisor and gce' do
       it 'returns a fact' do
-        expected_fact = double(Facter::ResolvedFact, name: 'hypervisors.kvm', value: { google: true })
+        expected_fact = instance_double(Facter::ResolvedFact, name: 'hypervisors.kvm', value: { google: true })
         allow(Facter::Resolvers::Windows::Virtualization).to receive(:resolve).with(:virtual).and_return('gce')
         allow(Facter::Resolvers::NetKVM).to receive(:resolve).with(:kvm).and_return(true)
         allow(Facter::Resolvers::DMIComputerSystem).to receive(:resolve).with(:name).and_return('value')
diff --git a/spec/facter/facts/windows/hypervisors/virtualbox_spec.rb b/spec/facter/facts/windows/hypervisors/virtualbox_spec.rb
index 23e3968f29..1c3b18cac4 100644
--- a/spec/facter/facts/windows/hypervisors/virtualbox_spec.rb
+++ b/spec/facter/facts/windows/hypervisors/virtualbox_spec.rb
@@ -4,7 +4,7 @@
   describe '#call_the_resolver' do
     context 'when is not Virtualbox hypervisor' do
       it 'returns nil' do
-        expected_fact = double(Facter::ResolvedFact, name: 'hypervisors.virtualbox', value: nil)
+        expected_fact = instance_double(Facter::ResolvedFact, name: 'hypervisors.virtualbox', value: nil)
         allow(Facter::Resolvers::Windows::Virtualization).to receive(:resolve).with(:virtual).and_return('value')
         allow(Facter::Resolvers::DMIComputerSystem).to receive(:resolve).with(:name).and_return('value')
         allow(Facter::ResolvedFact).to receive(:new).with('hypervisors.virtualbox', nil).and_return(expected_fact)
@@ -16,7 +16,7 @@
 
     context 'when is VirtualBox hypervisor and CpuidSource resolver returns the required output' do
       it 'returns a fact' do
-        expected_fact = double(Facter::ResolvedFact, name: 'hypervisors.virtualbox', value:
+        expected_fact = instance_double(Facter::ResolvedFact, name: 'hypervisors.virtualbox', value:
             { revision: ' 13.4', version: ' 13.4' })
         allow(Facter::Resolvers::Windows::Virtualization).to receive(:resolve).with(:virtual).and_return('virtualbox')
         allow(Facter::Resolvers::Windows::Virtualization)
@@ -33,7 +33,7 @@
 
     context 'when is VirtualBox hypervisor and DMIComputerSystem resolver returns the required output' do
       it 'returns a fact' do
-        expected_fact = double(Facter::ResolvedFact, name: 'hypervisors.virtualbox', value:
+        expected_fact = instance_double(Facter::ResolvedFact, name: 'hypervisors.virtualbox', value:
             { revision: '', version: '' })
         allow(Facter::Resolvers::Windows::Virtualization).to receive(:resolve).with(:virtual).and_return('value')
         allow(Facter::Resolvers::DMIComputerSystem).to receive(:resolve).with(:name).and_return('VirtualBox')
diff --git a/spec/facter/facts/windows/hypervisors/vmware_spec.rb b/spec/facter/facts/windows/hypervisors/vmware_spec.rb
index 22cfd83915..8409de3777 100644
--- a/spec/facter/facts/windows/hypervisors/vmware_spec.rb
+++ b/spec/facter/facts/windows/hypervisors/vmware_spec.rb
@@ -4,7 +4,7 @@
   describe '#call_the_resolver' do
     context 'when is not VMware hypervisor' do
       it 'returns nil' do
-        expected_fact = double(Facter::ResolvedFact, name: 'hypervisors.vmware', value: nil)
+        expected_fact = instance_double(Facter::ResolvedFact, name: 'hypervisors.vmware', value: nil)
         allow(Facter::Resolvers::Windows::Virtualization).to receive(:resolve).with(:virtual).and_return('value')
         allow(Facter::Resolvers::DMIBios).to receive(:resolve).with(:manufacturer).and_return('value')
         allow(Facter::ResolvedFact).to receive(:new).with('hypervisors.vmware', nil).and_return(expected_fact)
@@ -16,7 +16,7 @@
 
     context 'when is VMware hypervisor and virtualization resolver returns the required output' do
       it 'returns a fact' do
-        expected_fact = double(Facter::ResolvedFact, name: 'hypervisors.vmware', value: {})
+        expected_fact = instance_double(Facter::ResolvedFact, name: 'hypervisors.vmware', value: {})
         allow(Facter::Resolvers::Windows::Virtualization).to receive(:resolve).with(:virtual).and_return('vmware')
         allow(Facter::ResolvedFact).to receive(:new).with('hypervisors.vmware', {}).and_return(expected_fact)
 
@@ -27,7 +27,7 @@
 
     context 'when is VMware hypervisor and DmiBios resolver returns the required output' do
       it 'returns a fact' do
-        expected_fact = double(Facter::ResolvedFact, name: 'hypervisors.vmware', value: {})
+        expected_fact = instance_double(Facter::ResolvedFact, name: 'hypervisors.vmware', value: {})
         allow(Facter::Resolvers::Windows::Virtualization).to receive(:resolve).with(:virtual).and_return('value')
         allow(Facter::Resolvers::DMIBios).to receive(:resolve).with(:manufacturer).and_return('VMware, Inc.')
         allow(Facter::ResolvedFact).to receive(:new).with('hypervisors.vmware', {}).and_return(expected_fact)
diff --git a/spec/facter/facts/windows/hypervisors/xen_spec.rb b/spec/facter/facts/windows/hypervisors/xen_spec.rb
index 17bdca285c..d28ab25c36 100644
--- a/spec/facter/facts/windows/hypervisors/xen_spec.rb
+++ b/spec/facter/facts/windows/hypervisors/xen_spec.rb
@@ -4,7 +4,7 @@
   describe '#call_the_resolver' do
     context 'when is not xen hypervisor' do
       it 'returns nil' do
-        expected_fact = double(Facter::ResolvedFact, name: 'hypervisors.xen', value: nil)
+        expected_fact = instance_double(Facter::ResolvedFact, name: 'hypervisors.xen', value: nil)
         allow(Facter::Resolvers::Windows::Virtualization).to receive(:resolve).with(:virtual).and_return('value')
         allow(Facter::ResolvedFact).to receive(:new).with('hypervisors.xen', nil).and_return(expected_fact)
 
@@ -15,7 +15,7 @@
 
     context 'when is xen hypervisor and context not hvm' do
       it 'returns a fact' do
-        expected_fact = double(Facter::ResolvedFact, name: 'hypervisors.xen', value: { context: 'pv' })
+        expected_fact = instance_double(Facter::ResolvedFact, name: 'hypervisors.xen', value: { context: 'pv' })
         allow(Facter::Resolvers::Windows::Virtualization).to receive(:resolve).with(:virtual).and_return('xen')
         allow(Facter::Resolvers::DMIComputerSystem).to receive(:resolve).with(:name).and_return('PV domU')
         allow(Facter::ResolvedFact).to receive(:new)
@@ -28,7 +28,7 @@
 
     context 'when is xen hypervisor and context hvm' do
       it 'returns a fact' do
-        expected_fact = double(Facter::ResolvedFact, name: 'hypervisors.xen', value: { context: 'hvm' })
+        expected_fact = instance_double(Facter::ResolvedFact, name: 'hypervisors.xen', value: { context: 'hvm' })
         allow(Facter::Resolvers::Windows::Virtualization).to receive(:resolve).with(:virtual).and_return('xen')
         allow(Facter::Resolvers::DMIComputerSystem).to receive(:resolve).with(:name).and_return('HVM domU')
         allow(Facter::ResolvedFact).to receive(:new)
diff --git a/spec/facter/facts/windows/identity/privileged_spec.rb b/spec/facter/facts/windows/identity/privileged_spec.rb
index 932d5d60a9..49288c9704 100644
--- a/spec/facter/facts/windows/identity/privileged_spec.rb
+++ b/spec/facter/facts/windows/identity/privileged_spec.rb
@@ -3,7 +3,7 @@
 describe Facts::Windows::Identity::Privileged do
   describe '#call_the_resolver' do
     it 'returns a fact' do
-      expected_fact = double(Facter::ResolvedFact, name: 'identity.privileged', value: 'value')
+      expected_fact = instance_double(Facter::ResolvedFact, name: 'identity.privileged', value: 'value')
       allow(Facter::Resolvers::Identity).to receive(:resolve).with(:privileged).and_return('value')
       allow(Facter::ResolvedFact).to receive(:new).with('identity.privileged', 'value').and_return(expected_fact)
 
diff --git a/spec/facter/facts/windows/memory/system/capacity_spec.rb b/spec/facter/facts/windows/memory/system/capacity_spec.rb
index 6656ce2dfd..1904d0095c 100644
--- a/spec/facter/facts/windows/memory/system/capacity_spec.rb
+++ b/spec/facter/facts/windows/memory/system/capacity_spec.rb
@@ -3,7 +3,7 @@
 describe Facts::Windows::Memory::System::Capacity do
   describe '#call_the_resolver' do
     it 'returns a fact' do
-      expected_fact = double(Facter::ResolvedFact, name: 'memory.system.capacity', value: 'value')
+      expected_fact = instance_double(Facter::ResolvedFact, name: 'memory.system.capacity', value: 'value')
       allow(Facter::Resolvers::Memory).to receive(:resolve).with(:capacity).and_return('value')
       allow(Facter::ResolvedFact).to receive(:new).with('memory.system.capacity', 'value').and_return(expected_fact)
 
diff --git a/spec/facter/facts/windows/memory/system/used_bytes_spec.rb b/spec/facter/facts/windows/memory/system/used_bytes_spec.rb
index 21194baced..7ac2053bbd 100644
--- a/spec/facter/facts/windows/memory/system/used_bytes_spec.rb
+++ b/spec/facter/facts/windows/memory/system/used_bytes_spec.rb
@@ -3,7 +3,7 @@
 describe Facts::Windows::Memory::System::UsedBytes do
   describe '#call_the_resolver' do
     it 'returns a fact' do
-      expected_fact = double(Facter::ResolvedFact, name: 'memory.system.used_bytes', value: 1024)
+      expected_fact = instance_double(Facter::ResolvedFact, name: 'memory.system.used_bytes', value: 1024)
       allow(Facter::Resolvers::Memory).to receive(:resolve).with(:used_bytes).and_return(1024)
       allow(Facter::ResolvedFact).to receive(:new).with('memory.system.used_bytes', 1024).and_return(expected_fact)
 
diff --git a/spec/facter/facts/windows/networking/interfaces_spec.rb b/spec/facter/facts/windows/networking/interfaces_spec.rb
index c0df6ca8e0..e20a39a7d1 100644
--- a/spec/facter/facts/windows/networking/interfaces_spec.rb
+++ b/spec/facter/facts/windows/networking/interfaces_spec.rb
@@ -3,7 +3,7 @@
 describe Facts::Windows::Networking::Interfaces do
   describe '#call_the_resolver' do
     it 'returns a fact' do
-      expected_fact = double(Facter::ResolvedFact, name: 'networking.interfaces', value: 'value')
+      expected_fact = instance_double(Facter::ResolvedFact, name: 'networking.interfaces', value: 'value')
       allow(Facter::Resolvers::Windows::Networking).to receive(:resolve).with(:interfaces).and_return('value')
       allow(Facter::ResolvedFact).to receive(:new).with('networking.interfaces', 'value').and_return(expected_fact)
 
diff --git a/spec/facter/facts/windows/networking/mtu_spec.rb b/spec/facter/facts/windows/networking/mtu_spec.rb
index a4616eb3dd..10b9dba2d5 100644
--- a/spec/facter/facts/windows/networking/mtu_spec.rb
+++ b/spec/facter/facts/windows/networking/mtu_spec.rb
@@ -3,7 +3,7 @@
 describe Facts::Windows::Networking::Mtu do
   describe '#call_the_resolver' do
     it 'returns a fact' do
-      expected_fact = double(Facter::ResolvedFact, name: 'networking.mtu', value: 'value')
+      expected_fact = instance_double(Facter::ResolvedFact, name: 'networking.mtu', value: 'value')
       allow(Facter::Resolvers::Windows::Networking).to receive(:resolve).with(:mtu).and_return('value')
       allow(Facter::ResolvedFact).to receive(:new).with('networking.mtu', 'value').and_return(expected_fact)
 
diff --git a/spec/facter/facts/windows/processors/models_spec.rb b/spec/facter/facts/windows/processors/models_spec.rb
index 4e69d7df36..1a444e7a97 100644
--- a/spec/facter/facts/windows/processors/models_spec.rb
+++ b/spec/facter/facts/windows/processors/models_spec.rb
@@ -3,7 +3,7 @@
 describe Facts::Windows::Processors::Models do
   describe '#call_the_resolver' do
     it 'returns a fact' do
-      expected_fact = double(Facter::ResolvedFact, name: 'processors.models', value: 'value')
+      expected_fact = instance_double(Facter::ResolvedFact, name: 'processors.models', value: 'value')
       allow(Facter::Resolvers::Processors).to receive(:resolve).with(:models).and_return('value')
       allow(Facter::ResolvedFact).to receive(:new).with('processors.models', 'value').and_return(expected_fact)
 
diff --git a/spec/facter/query_parser_spec.rb b/spec/facter/query_parser_spec.rb
index 360a5311b5..d1e3f11f73 100644
--- a/spec/facter/query_parser_spec.rb
+++ b/spec/facter/query_parser_spec.rb
@@ -8,9 +8,9 @@
       os_name_class = 'Facter::Ubuntu::OsName'
       os_family_class = 'Facter::Ubuntu::OsFamily'
 
-      loaded_fact_os_name = double(Facter::LoadedFact, name: 'os.name', klass: os_name_class, type: :core, file: nil)
-      loaded_fact_os_family = double(Facter::LoadedFact, name: 'os.family', klass: os_family_class, type: :core,
-                                                         file: nil)
+      loaded_fact_os_name = instance_double(Facter::LoadedFact, name: 'os.name', klass: os_name_class, type: :core, file: nil)
+      loaded_fact_os_family = instance_double(Facter::LoadedFact, name: 'os.family', klass: os_family_class, type: :core,
+                                                                  file: nil)
       loaded_facts = [loaded_fact_os_name, loaded_fact_os_family]
 
       matched_facts = Facter::QueryParser.parse(query_list, loaded_facts)
@@ -25,10 +25,10 @@
       networking_class = 'Facter::Ubuntu::NetworkInterface'
       os_family_class = 'Facter::Ubuntu::OsFamily'
 
-      loaded_fact_networking = double(Facter::LoadedFact, name: 'ipaddress_.*', klass: networking_class, type: :legacy,
-                                                          file: nil)
-      loaded_fact_os_family = double(Facter::LoadedFact, name: 'os.family', klass: os_family_class, type: :core,
-                                                         file: nil)
+      loaded_fact_networking = instance_double(Facter::LoadedFact, name: 'ipaddress_.*', klass: networking_class, type: :legacy,
+                                                                   file: nil)
+      loaded_fact_os_family = instance_double(Facter::LoadedFact, name: 'os.family', klass: os_family_class, type: :core,
+                                                                  file: nil)
       loaded_facts = [loaded_fact_networking, loaded_fact_os_family]
 
       matched_facts = Facter::QueryParser.parse(query_list, loaded_facts)
@@ -57,8 +57,8 @@
       query_list = ['custom_fact']
       os_name_class = 'Facter::Ubuntu::OsName'
 
-      loaded_fact_os_name = double(Facter::LoadedFact, name: 'os.name', klass: os_name_class, type: :core, file: nil)
-      loaded_fact_custom_fact = double(Facter::LoadedFact, name: 'custom_fact', klass: nil, type: :custom, file: nil)
+      loaded_fact_os_name = instance_double(Facter::LoadedFact, name: 'os.name', klass: os_name_class, type: :core, file: nil)
+      loaded_fact_custom_fact = instance_double(Facter::LoadedFact, name: 'custom_fact', klass: nil, type: :custom, file: nil)
       loaded_facts = [loaded_fact_os_name, loaded_fact_custom_fact]
 
       matched_facts = Facter::QueryParser.parse(query_list, loaded_facts)
@@ -70,7 +70,7 @@
     it 'queries if param is symbol' do
       query_list = [:path]
       path_class = 'Facter::Ubuntu::Path'
-      loaded_fact_path = double(Facter::LoadedFact, name: 'path', klass: path_class, type: :core, file: nil)
+      loaded_fact_path = instance_double(Facter::LoadedFact, name: 'path', klass: path_class, type: :core, file: nil)
       loaded_facts = [loaded_fact_path]
 
       matched_facts = Facter::QueryParser.parse(query_list, loaded_facts)
@@ -84,9 +84,9 @@
         query_list = ['ldom.domainrole.impl']
         ldom_class = 'Facter::Solaris::Ldom'
 
-        loaded_fact_ldom = double(Facter::LoadedFact, name: 'ldom', klass: ldom_class, type: :core, file: nil)
-        ldom_fact_ldom_alias = double(Facter::LoadedFact, name: 'ldom_domainrole_impl', klass: ldom_class,
-                                                          type: :legacy, file: nil)
+        loaded_fact_ldom = instance_double(Facter::LoadedFact, name: 'ldom', klass: ldom_class, type: :core, file: nil)
+        ldom_fact_ldom_alias = instance_double(Facter::LoadedFact, name: 'ldom_domainrole_impl', klass: ldom_class,
+                                                                   type: :legacy, file: nil)
         loaded_facts = [loaded_fact_ldom, ldom_fact_ldom_alias]
 
         matched_facts = Facter::QueryParser.parse(query_list, loaded_facts)
@@ -112,7 +112,7 @@
 
     context 'when a fact name contains a regex special character' do
       let(:query_list) { ['regex(string'] }
-      let(:loaded_facts) { [double(Facter::LoadedFact, name: 'a_loaded_fact', klass: nil, type: :custom, file: nil)] }
+      let(:loaded_facts) { [instance_double(Facter::LoadedFact, name: 'a_loaded_fact', klass: nil, type: :custom, file: nil)] }
 
       it 'is escaped correctly and does not result in an unexpected regex parse error' do
         matched_facts = Facter::QueryParser.parse(query_list, loaded_facts)
diff --git a/spec/facter/resolvers/freebsd/ffi_helper_spec.rb b/spec/facter/resolvers/freebsd/ffi_helper_spec.rb
index 17302ae79b..9abc41520e 100644
--- a/spec/facter/resolvers/freebsd/ffi_helper_spec.rb
+++ b/spec/facter/resolvers/freebsd/ffi_helper_spec.rb
@@ -36,7 +36,7 @@
 
     context 'when expecting an uint32_t' do
       let(:result) { 42 }
-      let(:oldlen) { double('Integer') }
+      let(:oldlen) { instance_double(Integer) }
 
       before do
         allow(FFI::MemoryPointer).to receive(:new)
diff --git a/spec/facter/resolvers/macosx/mountpoints_spec.rb b/spec/facter/resolvers/macosx/mountpoints_spec.rb
index f729ae92ae..a8def81cdb 100644
--- a/spec/facter/resolvers/macosx/mountpoints_spec.rb
+++ b/spec/facter/resolvers/macosx/mountpoints_spec.rb
@@ -8,14 +8,14 @@ class Error < StandardError; end
 
 describe Facter::Resolvers::Macosx::Mountpoints do
   let(:mount) do
-    double(Sys::Filesystem::Mount, mount_type: 'ext4', mount_point: '/proc/a', options: mount_options,
-                                   name: '/dev/nvme0n1p2', dump_frequency: 0, pass_number: 0)
+    instance_double(Sys::Filesystem::Mount, mount_type: 'ext4', mount_point: '/proc/a',
+                                            options: mount_options, name: '/dev/nvme0n1p2', dump_frequency: 0, pass_number: 0)
   end
 
   let(:stat) do
-    double(Sys::Filesystem::Stat,
-           path: '/proc/a', base_type: nil, fragment_size: 4096, block_size: 4096, blocks: 113_879_332,
-           blocks_available: 16_596_603, blocks_free: 22_398_776)
+    instance_double(Sys::Filesystem::Stat, path: '/proc/a', base_type: nil, fragment_size: 4096,
+                                           block_size: 4096, blocks: 113_879_332,
+                                           blocks_available: 16_596_603, blocks_free: 22_398_776)
   end
 
   let(:fact) do
@@ -57,8 +57,8 @@ class Error < StandardError; end
     let(:fact_options) { %w[rw noatime] }
 
     let(:mount) do
-      double(Sys::Filesystem::Mount, mount_point: '/', mount_type: 'ext4', options: mount_options,
-                                     name: '/dev/root')
+      instance_double(Sys::Filesystem::Mount, mount_point: '/', mount_type: 'ext4', options: mount_options,
+                                              name: '/dev/root')
     end
 
     it 'looks up the actual device if /dev/root' do
diff --git a/spec/facter/resolvers/mountpoints_spec.rb b/spec/facter/resolvers/mountpoints_spec.rb
index 9618a08633..177487b170 100644
--- a/spec/facter/resolvers/mountpoints_spec.rb
+++ b/spec/facter/resolvers/mountpoints_spec.rb
@@ -2,16 +2,16 @@
 
 describe Facter::Resolvers::Mountpoints do
   let(:mount) do
-    double(Sys::Filesystem::Mount,
-           mount_point: '/', mount_time: nil,
-           mount_type: 'ext4', options: 'rw,noatime', name:
-           '/dev/nvme0n1p2', dump_frequency: 0, pass_number: 0)
+    instance_double(Sys::Filesystem::Mount,
+                    mount_point: '/', mount_time: nil,
+                    mount_type: 'ext4', options: 'rw,noatime',
+                    name: '/dev/nvme0n1p2', dump_frequency: 0, pass_number: 0)
   end
 
   let(:stat) do
-    double(Sys::Filesystem::Stat,
-           path: '/', base_type: nil, fragment_size: 4096, block_size: 4096, blocks: 113_879_332,
-           blocks_available: -16_596_603, blocks_free: 22_398_776)
+    instance_double(Sys::Filesystem::Stat,
+                    path: '/', base_type: nil, fragment_size: 4096, block_size: 4096, blocks: 113_879_332,
+                    blocks_available: -16_596_603, blocks_free: 22_398_776)
   end
 
   let(:fact) do
@@ -29,8 +29,8 @@
   end
 
   let(:ignored_mounts) do
-    [double(Sys::Filesystem::Mount, mount_type: 'ext4', mount_point: '/proc/a', name: '/dev/ignore', options: 'rw'),
-     double(Sys::Filesystem::Mount, mount_type: 'autofs', mount_point: '/mnt/auto', name: '/dev/ignore', options: 'rw')]
+    [instance_double(Sys::Filesystem::Mount, mount_type: 'ext4', mount_point: '/proc/a', name: '/dev/ignore', options: 'rw'),
+     instance_double(Sys::Filesystem::Mount, mount_type: 'autofs', mount_point: '/mnt/auto', name: '/dev/ignore', options: 'rw')]
   end
 
   before do
@@ -109,7 +109,7 @@
 
   describe '.root_device' do
     let(:mount) do
-      double(Sys::Filesystem::Mount, mount_point: '/', mount_type: 'ext4', options: 'rw,noatime', name: '/dev/root')
+      instance_double(Sys::Filesystem::Mount, mount_point: '/', mount_type: 'ext4', options: 'rw,noatime', name: '/dev/root')
     end
 
     it 'looks up the actual device if /dev/root' do
diff --git a/spec/facter/resolvers/solaris/mountpoints_spec.rb b/spec/facter/resolvers/solaris/mountpoints_spec.rb
index c5934df05d..4bc4a0c4f5 100644
--- a/spec/facter/resolvers/solaris/mountpoints_spec.rb
+++ b/spec/facter/resolvers/solaris/mountpoints_spec.rb
@@ -4,39 +4,39 @@
   let(:resolver) { Facter::Resolvers::Solaris::Mountpoints }
   let(:mounts) do
     [
-      object_double(Sys::Filesystem::Mount,
-                    mount_point: '/', mount_time: nil,
-                    mount_type: 'zfs', options: 'dev=4490002', name:
-                    'rpool/ROOT/solaris', dump_frequency: nil, pass_number: nil),
-      object_double(Sys::Filesystem::Mount,
-                    mount_point: '/devices', mount_time: nil,
-                    mount_type: 'devfs', options: 'dev=8580000', name:
-                    '/devices', dump_frequency: nil, pass_number: nil),
-      object_double(Sys::Filesystem::Mount,
-                    mount_point: '/proc', mount_time: nil,
-                    mount_type: 'proc', options: 'dev=8600000', name:
-                    'proc', dump_frequency: nil, pass_number: nil),
-      object_double(Sys::Filesystem::Mount,
-                    mount_point: '/net', mount_time: nil,
-                    mount_type: 'autofs', options: 'nosuid,indirect,ignore,nobrowse,dev=8900007', name:
-                    '-hosts', dump_frequency: nil, pass_number: nil),
-      object_double(Sys::Filesystem::Mount,
-                    mount_point: '/home', mount_time: nil,
-                    mount_type: 'autofs', options: 'indirect,ignore,nobrowse,dev=8900008', name:
-                    'auto_home', dump_frequency: nil, pass_number: nil),
-      object_double(Sys::Filesystem::Mount,
-                    mount_point: '/home/user', mount_time: nil,
-                    mount_type: 'zfs', options: 'dev=8900009', name:
-                    'rpool/user', dump_frequency: nil, pass_number: nil)
+      instance_double(Sys::Filesystem::Mount,
+                      mount_point: '/', mount_time: nil,
+                      mount_type: 'zfs', options: 'dev=4490002', name:
+                      'rpool/ROOT/solaris', dump_frequency: nil, pass_number: nil),
+      instance_double(Sys::Filesystem::Mount,
+                      mount_point: '/devices', mount_time: nil,
+                      mount_type: 'devfs', options: 'dev=8580000', name:
+                      '/devices', dump_frequency: nil, pass_number: nil),
+      instance_double(Sys::Filesystem::Mount,
+                      mount_point: '/proc', mount_time: nil,
+                      mount_type: 'proc', options: 'dev=8600000', name:
+                      'proc', dump_frequency: nil, pass_number: nil),
+      instance_double(Sys::Filesystem::Mount,
+                      mount_point: '/net', mount_time: nil,
+                      mount_type: 'autofs', options: 'nosuid,indirect,ignore,nobrowse,dev=8900007', name:
+                      '-hosts', dump_frequency: nil, pass_number: nil),
+      instance_double(Sys::Filesystem::Mount,
+                      mount_point: '/home', mount_time: nil,
+                      mount_type: 'autofs', options: 'indirect,ignore,nobrowse,dev=8900008', name:
+                      'auto_home', dump_frequency: nil, pass_number: nil),
+      instance_double(Sys::Filesystem::Mount,
+                      mount_point: '/home/user', mount_time: nil,
+                      mount_type: 'zfs', options: 'dev=8900009', name:
+                      'rpool/user', dump_frequency: nil, pass_number: nil)
     ]
   end
 
   let(:mount) { mounts.first }
 
   let(:stat) do
-    object_double('Sys::Filesystem::Stat',
-                  path: '/', base_type: 'zfs', fragment_size: 512, block_size: 131_072, blocks: 20_143_706,
-                  blocks_available: 11_731_043, blocks_free: 11_731_043)
+    instance_double('Sys::Filesystem::Stat',
+                    path: '/', base_type: 'zfs', fragment_size: 512, block_size: 131_072, blocks: 20_143_706,
+                    blocks_available: 11_731_043, blocks_free: 11_731_043)
   end
 
   let(:fact) do
diff --git a/spec/framework/core/fact_loaders/external_fact_loader_spec.rb b/spec/framework/core/fact_loaders/external_fact_loader_spec.rb
index 84e541b685..5c3e8a47cd 100644
--- a/spec/framework/core/fact_loaders/external_fact_loader_spec.rb
+++ b/spec/framework/core/fact_loaders/external_fact_loader_spec.rb
@@ -1,7 +1,7 @@
 # frozen_string_literal: true
 
 describe Facter::ExternalFactLoader do
-  let(:collection) { double(LegacyFacter::Util::Collection) }
+  let(:collection) { instance_double(LegacyFacter::Util::Collection) }
   let(:external_fact) { Facter::Util::Fact.new('external_fact', options: { fact_type: :external }) }
   let(:custom_fact) { Facter::Util::Fact.new('custom_fact', options: { fact_type: :custom }) }
 
diff --git a/spec/framework/core/session_cache_spec.rb b/spec/framework/core/session_cache_spec.rb
index 4b0c9da822..e6a857bbcf 100644
--- a/spec/framework/core/session_cache_spec.rb
+++ b/spec/framework/core/session_cache_spec.rb
@@ -1,12 +1,12 @@
 # frozen_string_literal: true
 
 describe Facter::SessionCache do
-  let(:uname_resolver) { spy(Facter::Resolvers::Uname) }
+  let(:uname_resolver) { Facter::Resolvers::Uname.new }
 
   it 'registers resolver subscription' do
-    Facter::SessionCache.subscribe(uname_resolver)
-    Facter::SessionCache.invalidate_all_caches
+    expect(uname_resolver.class).to receive(:invalidate_cache)
 
-    expect(uname_resolver).to have_received(:invalidate_cache)
+    Facter::SessionCache.subscribe(uname_resolver.class)
+    Facter::SessionCache.invalidate_all_caches
   end
 end
diff --git a/spec/framework/formatters/hocon_fact_formatter_spec.rb b/spec/framework/formatters/hocon_fact_formatter_spec.rb
index 59d05bc0e3..8d1838a9c2 100644
--- a/spec/framework/formatters/hocon_fact_formatter_spec.rb
+++ b/spec/framework/formatters/hocon_fact_formatter_spec.rb
@@ -3,14 +3,14 @@
 describe Facter::HoconFactFormatter do
   it 'formats to hocon when no user query' do
     resolved_fact1 =
-      double(Facter::ResolvedFact, name: 'os.name', value: 'Darwin',
-                                   user_query: '', type: :core)
+      instance_double(Facter::ResolvedFact, name: 'os.name', value: 'Darwin',
+                                            user_query: '', type: :core)
     resolved_fact2 =
-      double(Facter::ResolvedFact, name: 'os.family', value: 'Darwin',
-                                   user_query: '', type: :core)
+      instance_double(Facter::ResolvedFact, name: 'os.family', value: 'Darwin',
+                                            user_query: '', type: :core)
     resolved_fact3 =
-      double(Facter::ResolvedFact, name: 'os.architecture', value: 'x86_64',
-                                   user_query: '', type: :core)
+      instance_double(Facter::ResolvedFact, name: 'os.architecture', value: 'x86_64',
+                                            user_query: '', type: :core)
     resolved_fact_list = [resolved_fact1, resolved_fact2, resolved_fact3]
 
     formatted_output = Facter::HoconFactFormatter.new.format(resolved_fact_list)
@@ -22,8 +22,8 @@
 
   it 'formats to hocon for a single user query' do
     resolved_fact =
-      double(Facter::ResolvedFact, name: 'os.name', value: 'Darwin',
-                                   user_query: 'os.name', type: :core)
+      instance_double(Facter::ResolvedFact, name: 'os.name', value: 'Darwin',
+                                            user_query: 'os.name', type: :core)
     resolved_fact_list = [resolved_fact]
     formatted_output = Facter::HoconFactFormatter.new.format(resolved_fact_list)
 
@@ -34,11 +34,11 @@
 
   it 'formats to hocon for multiple user queries' do
     resolved_fact1 =
-      double(Facter::ResolvedFact, name: 'os.name', value: 'Darwin',
-                                   user_query: 'os.name', type: :core)
+      instance_double(Facter::ResolvedFact, name: 'os.name', value: 'Darwin',
+                                            user_query: 'os.name', type: :core)
     resolved_fact2 =
-      double(Facter::ResolvedFact, name: 'os.family', value: 'Darwin',
-                                   user_query: 'os.family', type: :core)
+      instance_double(Facter::ResolvedFact, name: 'os.family', value: 'Darwin',
+                                            user_query: 'os.family', type: :core)
     resolved_fact_list = [resolved_fact1, resolved_fact2]
     formatted_output = Facter::HoconFactFormatter.new.format(resolved_fact_list)
 
@@ -55,8 +55,8 @@
 
   it 'returns empty string when the fact value is nil' do
     resolved_fact1 =
-      double(Facter::ResolvedFact, name: 'my_external_fact', value: nil,
-                                   user_query: 'my_external_fact', type: :core)
+      instance_double(Facter::ResolvedFact, name: 'my_external_fact', value: nil,
+                                            user_query: 'my_external_fact', type: :core)
     resolved_fact_list = [resolved_fact1]
 
     formatted_output = Facter::HoconFactFormatter.new.format(resolved_fact_list)
diff --git a/spec/framework/formatters/json_fact_formatter_spec.rb b/spec/framework/formatters/json_fact_formatter_spec.rb
index 13aca0c02d..e9928c03e9 100644
--- a/spec/framework/formatters/json_fact_formatter_spec.rb
+++ b/spec/framework/formatters/json_fact_formatter_spec.rb
@@ -3,18 +3,16 @@
 describe Facter::JsonFactFormatter do
   it 'formats to json when no user query' do
     resolved_fact1 =
-      double(Facter::ResolvedFact, name: 'os.name', value: 'Darwin',
-                                   user_query: '', type: :core)
+      instance_double(Facter::ResolvedFact, name: 'os.name', value: 'Darwin',
+                                            user_query: '', type: :core)
     resolved_fact2 =
-      double(Facter::ResolvedFact, name: 'os.family', value: 'Darwin',
-                                   user_query: '', type: :core)
+      instance_double(Facter::ResolvedFact, name: 'os.family', value: 'Darwin',
+                                            user_query: '', type: :core)
     resolved_fact3 =
-      double(Facter::ResolvedFact, name: 'os.architecture', value: 'x86_64',
-                                   user_query: '', type: :core)
+      instance_double(Facter::ResolvedFact, name: 'os.architecture', value: 'x86_64',
+                                            user_query: '', type: :core)
     resolved_fact_list = [resolved_fact1, resolved_fact2, resolved_fact3]
 
-    double
-
     formatted_output = Facter::JsonFactFormatter.new.format(resolved_fact_list)
 
     expected_output =
@@ -25,8 +23,8 @@
 
   it 'formats to json for a single user query' do
     resolved_fact =
-      double(Facter::ResolvedFact, name: 'os.name', value: 'Darwin',
-                                   user_query: 'os.name', type: :core)
+      instance_double(Facter::ResolvedFact, name: 'os.name', value: 'Darwin',
+                                            user_query: 'os.name', type: :core)
     resolved_fact_list = [resolved_fact]
     formatted_output = Facter::JsonFactFormatter.new.format(resolved_fact_list)
 
@@ -37,11 +35,11 @@
 
   it 'formats to json for multiple user queries' do
     resolved_fact1 =
-      double(Facter::ResolvedFact, name: 'os.name', value: 'Darwin',
-                                   user_query: 'os.name', type: :core)
+      instance_double(Facter::ResolvedFact, name: 'os.name', value: 'Darwin',
+                                            user_query: 'os.name', type: :core)
     resolved_fact2 =
-      double(Facter::ResolvedFact, name: 'os.family', value: 'Darwin',
-                                   user_query: 'os.family', type: :core)
+      instance_double(Facter::ResolvedFact, name: 'os.family', value: 'Darwin',
+                                            user_query: 'os.family', type: :core)
     resolved_fact_list = [resolved_fact1, resolved_fact2]
     formatted_output = Facter::JsonFactFormatter.new.format(resolved_fact_list)
 
diff --git a/spec/mocks/sys_filesystem.rb b/spec/mocks/sys_filesystem.rb
index 10fadb3bb0..1aca75d121 100644
--- a/spec/mocks/sys_filesystem.rb
+++ b/spec/mocks/sys_filesystem.rb
@@ -5,43 +5,92 @@ class Filesystem
     def self.mounts; end
 
     class Mount
-      def self.mount_point; end
+      # The name of the mounted resource.
+      attr_accessor :name
 
-      def self.mount_type; end
+      # The mount point/directory.
+      attr_accessor :mount_point
 
-      def self.options; end
+      # The type of filesystem mount, e.g. ufs, nfs, etc.
+      attr_accessor :mount_type
 
-      def self.mount_time; end
+      # A list of comma separated options for the mount, e.g. nosuid, etc.
+      attr_accessor :options
 
-      def self.name; end
+      # The time the filesystem was mounted. May be nil.
+      attr_accessor :mount_time
 
-      def self.dump_frequency; end
+      # The dump frequency in days. May be nil.
+      attr_accessor :dump_frequency
 
-      def self.pass_number; end
+      # The pass number of the filessytem check. May be nil.
+      attr_accessor :pass_number
     end
 
     class Stat
-      def self.path; end
+      # The path of the filesystem.
+      attr_accessor :path
 
-      def self.base_type; end
+      # The preferred system block size.
+      attr_accessor :block_size
 
-      def self.fragment_size; end
+      # The fragment size, i.e. fundamental filesystem block size.
+      attr_accessor :fragment_size
 
-      def self.block_size; end
+      # The total number of +fragment_size+ blocks in the filesystem.
+      attr_accessor :blocks
 
-      def self.blocks; end
+      # The total number of free blocks in the filesystem.
+      attr_accessor :blocks_free
 
-      def self.blocks_available; end
+      # The number of free blocks available to unprivileged processes.
+      attr_accessor :blocks_available
 
-      def self.blocks_free; end
+      # The total number of files/inodes that can be created.
+      attr_accessor :files
 
-      def self.bytes_total; end
+      # The total number of files/inodes on the filesystem.
+      attr_accessor :files_free
 
-      def self.bytes_available; end
+      # The number of free files/inodes available to unprivileged processes.
+      attr_accessor :files_available
 
-      def self.bytes_free; end
+      # The filesystem identifier.
+      attr_accessor :filesystem_id
 
-      def self.bytes_used; end
+      # A bit mask of flags.
+      attr_accessor :flags
+
+      # The maximum length of a file name permitted on the filesystem.
+      attr_accessor :name_max
+
+      # The filesystem type, e.g. UFS.
+      attr_accessor :base_type
+
+      # Returns the total space on the partition.
+      def bytes_total
+        blocks * fragment_size
+      end
+
+      # Returns the total amount of free space on the partition.
+      def bytes_free
+        blocks_free * fragment_size
+      end
+
+      # Returns the amount of free space available to unprivileged processes.
+      def bytes_available
+        blocks_available * fragment_size
+      end
+
+      # Returns the total amount of used space on the partition.
+      def bytes_used
+        bytes_total - bytes_free
+      end
+
+      # Returns the percentage of the partition that has been used.
+      def percent_used
+        100 - (100.0 * bytes_free.to_f / bytes_total.to_f)
+      end
     end
   end
 end
diff --git a/spec/mocks/util.rb b/spec/mocks/util.rb
index bbd5344bff..dd10dd7453 100644
--- a/spec/mocks/util.rb
+++ b/spec/mocks/util.rb
@@ -27,26 +27,26 @@ def mock_query_parser(user_query, loaded_fact_hash)
     .with(user_query, loaded_fact_hash)
 end
 
-private_methods def allow_attr_change(resolved_fact_mock, fact_name, fact_value)
+private_methods def allow_attr_change(resolved_fact_mock, fact_value)
   allow(resolved_fact_mock)
     .to receive(:value=)
     .with(fact_value)
 
-  allow(resolved_fact_mock)
-    .to receive(:name=)
-    .with(fact_name)
-
   allow(resolved_fact_mock)
     .to receive(:user_query=)
 end
 
 def mock_resolved_fact(fact_name, fact_value, user_query = nil, type = :core)
-  resolved_fact_mock = double(Facter::ResolvedFact, name: fact_name, value: fact_value,
-                                                    user_query: user_query, type: type,
-                                                    legacy?: type == :legacy, core?: type == :core, file: nil,
-                                                    resolves?: fact_name == user_query)
+  resolved_fact_mock = instance_double(
+    Facter::ResolvedFact, name: fact_name, value: fact_value,
+                          user_query: user_query, type: type,
+                          legacy?: type == :legacy,
+                          core?: type == :core,
+                          file: nil,
+                          resolves?: fact_name == user_query
+  )
 
-  allow_attr_change(resolved_fact_mock, fact_name, fact_value)
+  allow_attr_change(resolved_fact_mock, fact_value)
   resolved_fact_mock
 end