diff --git a/lib/puppet/defaults.rb b/lib/puppet/defaults.rb
index 97fed251066..9d1757863b7 100644
--- a/lib/puppet/defaults.rb
+++ b/lib/puppet/defaults.rb
@@ -47,29 +47,15 @@ def self.default_cadir
   end
 
   def self.default_basemodulepath
-    if Puppet::Util::Platform.windows?
-      path = ['$codedir/modules']
-      installdir = ENV.fetch("FACTER_env_windows_installdir", nil)
-      if installdir
-        path << "#{installdir}/puppet/modules"
-      end
-      path.join(File::PATH_SEPARATOR)
-    else
-      '$codedir/modules:/opt/puppetlabs/puppet/modules'
+    path = ['$codedir/modules']
+    if (run_mode_dir = Puppet.run_mode.common_module_dir)
+      path << run_mode_dir
     end
+    path.join(File::PATH_SEPARATOR)
   end
 
   def self.default_vendormoduledir
-    if Puppet::Util::Platform.windows?
-      installdir = ENV.fetch("FACTER_env_windows_installdir", nil)
-      if installdir
-        "#{installdir}\\puppet\\vendor_modules"
-      else
-        nil
-      end
-    else
-      '/opt/puppetlabs/puppet/vendor_modules'
-    end
+    Puppet.run_mode.vendor_module_dir
   end
 
   ############################################################################################
diff --git a/lib/puppet/provider/package/gem.rb b/lib/puppet/provider/package/gem.rb
index c0a46c1a4e9..88dab6768e2 100644
--- a/lib/puppet/provider/package/gem.rb
+++ b/lib/puppet/provider/package/gem.rb
@@ -83,6 +83,7 @@ def self.execute_gem_command(command, command_options, custom_environment = {})
       custom_environment[:PATH] = windows_path_without_puppet_bin
     end
 
+    # This uses an unusual form of passing the command and args as [<cmd>, [<arg1>, <arg2>, ...]]
     execute(cmd, { :failonfail => true, :combine => true, :custom_environment => custom_environment })
   end
 
diff --git a/lib/puppet/provider/package/puppet_gem.rb b/lib/puppet/provider/package/puppet_gem.rb
index 3adde08a2d9..3578a05c197 100644
--- a/lib/puppet/provider/package/puppet_gem.rb
+++ b/lib/puppet/provider/package/puppet_gem.rb
@@ -8,20 +8,7 @@
 
   confine :true => Puppet.runtime[:facter].value(:aio_agent_version)
 
-  def self.windows_gemcmd
-    puppet_dir = ENV.fetch('PUPPET_DIR', nil)
-    if puppet_dir
-      File.join(puppet_dir.to_s, 'bin', 'gem.bat')
-    else
-      File.join(Gem.default_bindir, 'gem.bat')
-    end
-  end
-
-  if Puppet::Util::Platform.windows?
-    commands :gemcmd => windows_gemcmd
-  else
-    commands :gemcmd => "/opt/puppetlabs/puppet/bin/gem"
-  end
+  commands :gemcmd => Puppet.run_mode.gem_cmd
 
   def uninstall
     super
@@ -30,7 +17,9 @@ def uninstall
   end
 
   def self.execute_gem_command(command, command_options, custom_environment = {})
-    custom_environment['PKG_CONFIG_PATH'] = '/opt/puppetlabs/puppet/lib/pkgconfig' unless Puppet::Util::Platform.windows?
+    if (pkg_config_path = Puppet.run_mode.pkg_config_path)
+      custom_environment['PKG_CONFIG_PATH'] = pkg_config_path
+    end
     super(command, command_options, custom_environment)
   end
 end
diff --git a/lib/puppet/util/run_mode.rb b/lib/puppet/util/run_mode.rb
index 06af3eea006..a64198150f4 100644
--- a/lib/puppet/util/run_mode.rb
+++ b/lib/puppet/util/run_mode.rb
@@ -87,6 +87,22 @@ def run_dir
       def log_dir
         which_dir("/var/log/puppetlabs/puppet", "~/.puppetlabs/var/log")
       end
+
+      def pkg_config_path
+        '/opt/puppetlabs/puppet/lib/pkgconfig'
+      end
+
+      def gem_cmd
+        '/opt/puppetlabs/puppet/bin/gem'
+      end
+
+      def common_module_dir
+        '/opt/puppetlabs/puppet/modules'
+      end
+
+      def vendor_module_dir
+        '/opt/puppetlabs/puppet/vendor_modules'
+      end
     end
 
     class WindowsRunMode < RunMode
@@ -114,8 +130,32 @@ def log_dir
         which_dir(File.join(windows_common_base("puppet/var/log")), "~/.puppetlabs/var/log")
       end
 
+      def pkg_config_path
+        nil
+      end
+
+      def gem_cmd
+        if (puppet_dir = ENV.fetch('PUPPET_DIR', nil))
+          File.join(puppet_dir.to_s, 'bin', 'gem.bat')
+        else
+          File.join(Gem.default_bindir, 'gem.bat')
+        end
+      end
+
+      def common_module_dir
+        "#{installdir}/puppet/modules" if installdir
+      end
+
+      def vendor_module_dir
+        "#{installdir}\\puppet\\vendor_modules" if installdir
+      end
+
       private
 
+      def installdir
+        ENV.fetch('FACTER_env_windows_installdir', nil)
+      end
+
       def windows_common_base(*extra)
         [ENV.fetch('ALLUSERSPROFILE', nil), "PuppetLabs"] + extra
       end
diff --git a/spec/unit/provider/package/puppet_gem_spec.rb b/spec/unit/provider/package/puppet_gem_spec.rb
index ea95d7aec1a..d2098ee3061 100644
--- a/spec/unit/provider/package/puppet_gem_spec.rb
+++ b/spec/unit/provider/package/puppet_gem_spec.rb
@@ -20,42 +20,26 @@
     let(:provider_gem_cmd) { '/opt/puppetlabs/puppet/bin/gem' }
   end
 
-  custom_environment = {"HOME"=>ENV["HOME"]}
-  custom_environment['PKG_CONFIG_PATH'] = '/opt/puppetlabs/puppet/lib/pkgconfig'
-
-  let(:execute_options) { {:failonfail => true, :combine => true, :custom_environment => custom_environment} }
+  let(:execute_options) do
+    {
+      failonfail: true,
+      combine: true,
+      custom_environment: {
+        'HOME'=>ENV['HOME'],
+        'PKG_CONFIG_PATH' => '/opt/puppetlabs/puppet/lib/pkgconfig'
+      }
+    }
+  end
 
   before :each do
     resource.provider = provider
-    allow(described_class).to receive(:command).with(:gemcmd).and_return(provider_gem_cmd)
-    allow(Puppet::Util::Platform).to receive(:windows?).and_return(false)
-  end
-
-
-  describe '.windows_gemcmd' do
-    context 'when PUPPET_DIR is not set' do
-      before do
-        # allow(ENV).to receive(:fetch, anything).and_call_original
-        allow(ENV).to receive(:fetch).with('PUPPET_DIR', anything).and_return(nil)
-        allow(Gem).to receive(:default_bindir).and_return('default_gem_bin')
-      end
-
-      it 'uses Gem.default_bindir' do
-        expected_path = File.join('default_gem_bin', 'gem.bat')
-        expect(described_class.windows_gemcmd).to eql(expected_path)
-      end
-    end
-
-    context 'when PUPPET_DIR is set' do
-      before do
-        allow(ENV).to receive(:fetch).with('PUPPET_DIR', anything).and_return('puppet_dir')
-      end
-
-      it 'uses Gem.default_bindir' do
-        expected_path = File.join('puppet_dir', 'bin', 'gem.bat')
-        expect(described_class.windows_gemcmd).to eql(expected_path)
-      end
+    if Puppet::Util::Platform.windows?
+      # provider is loaded before we can stub, so stub the class we're testing
+      allow(provider.class).to receive(:command).with(:gemcmd).and_return(provider_gem_cmd)
+    else
+      allow(provider.class).to receive(:which).with(provider_gem_cmd).and_return(provider_gem_cmd)
     end
+    allow(File).to receive(:file?).with(provider_gem_cmd).and_return(true)
   end
 
   context "when installing" do
@@ -64,45 +48,43 @@
     end
 
     it "should use the path to the gem command" do
-      allow(described_class).to receive(:validate_command).with(provider_gem_cmd)
-      expect(described_class).to receive(:execute).with(be_a(Array), execute_options) { |args| expect(args[0]).to eq(provider_gem_cmd) }.and_return('')
+      expect(described_class).to receive(:execute).with([provider_gem_cmd, be_an(Array)], be_a(Hash)).and_return('')
       provider.install
     end
 
     it "should not append install_options by default" do
-      expect(described_class).to receive(:execute_gem_command).with(provider_gem_cmd, %w{install --no-rdoc --no-ri myresource}).and_return('')
+      expect(described_class).to receive(:execute).with([provider_gem_cmd, %w{install --no-rdoc --no-ri myresource}], anything).and_return('')
       provider.install
     end
 
     it "should allow setting an install_options parameter" do
       resource[:install_options] = [ '--force', {'--bindir' => '/usr/bin' } ]
-      expect(described_class).to receive(:execute_gem_command).with(provider_gem_cmd, %w{install --force --bindir=/usr/bin --no-rdoc --no-ri myresource}).and_return('')
+      expect(described_class).to receive(:execute).with([provider_gem_cmd, %w{install --force --bindir=/usr/bin --no-rdoc --no-ri myresource}], anything).and_return('')
       provider.install
     end
   end
 
   context "when uninstalling" do
     it "should use the path to the gem command" do
-      allow(described_class).to receive(:validate_command).with(provider_gem_cmd)
-      expect(described_class).to receive(:execute).with(be_a(Array), execute_options) { |args| expect(args[0]).to eq(provider_gem_cmd) }.and_return('')
+      expect(described_class).to receive(:execute).with([provider_gem_cmd, be_an(Array)], be_a(Hash)).and_return('')
       provider.uninstall
     end
 
     it "should not append uninstall_options by default" do
-      expect(described_class).to receive(:execute_gem_command).with(provider_gem_cmd, %w{uninstall --executables --all myresource}).and_return('')
+      expect(described_class).to receive(:execute).with([provider_gem_cmd, %w{uninstall --executables --all myresource}], anything).and_return('')
       provider.uninstall
     end
 
     it "should allow setting an uninstall_options parameter" do
       resource[:uninstall_options] = [ '--force', {'--bindir' => '/usr/bin' } ]
-      expect(described_class).to receive(:execute_gem_command).with(provider_gem_cmd, %w{uninstall --executables --all myresource --force --bindir=/usr/bin}).and_return('')
+      expect(described_class).to receive(:execute).with([provider_gem_cmd, %w{uninstall --executables --all myresource --force --bindir=/usr/bin}], anything).and_return('')
       provider.uninstall
     end
 
     it 'should invalidate the rubygems cache' do
       gem_source = double('gem_source')
       allow(Puppet::Util::Autoload).to receive(:gem_source).and_return(gem_source)
-      expect(described_class).to receive(:execute_gem_command).with(provider_gem_cmd, %w{uninstall --executables --all myresource}).and_return('')
+      expect(described_class).to receive(:execute).with([provider_gem_cmd, %w{uninstall --executables --all myresource}], anything).and_return('')
       expect(gem_source).to receive(:clear_paths)
       provider.uninstall
     end
@@ -125,5 +107,4 @@
       it { is_expected.to be > 100 }
     end
   end
-
 end
diff --git a/spec/unit/provider/package/puppetserver_gem_spec.rb b/spec/unit/provider/package/puppetserver_gem_spec.rb
index da4b9082784..69f6c3a815e 100644
--- a/spec/unit/provider/package/puppetserver_gem_spec.rb
+++ b/spec/unit/provider/package/puppetserver_gem_spec.rb
@@ -16,37 +16,37 @@
 
   let(:provider_gem_cmd) { '/opt/puppetlabs/bin/puppetserver' }
 
-  custom_environment = { HOME: ENV['HOME'] }
-
-  let(:execute_options) { { failonfail: true, combine: true, custom_environment: custom_environment } }
+  let(:execute_options) do
+    { failonfail: true, combine: true, custom_environment: { 'HOME' => ENV['HOME'] } }
+  end
 
   before :each do
     resource.provider = provider
     allow(Puppet::Util).to receive(:which).with(provider_gem_cmd).and_return(provider_gem_cmd)
+    allow(File).to receive(:file?).with(provider_gem_cmd).and_return(true)
   end
 
   describe "#install" do
     it "uses the path to the gem command" do
-      allow(described_class).to receive(:validate_command).with(provider_gem_cmd)
-      expect(Puppet::Util::Execution).to receive(:execute).with(be_a(Array), execute_options) { |args| expect(args[0]).to eq(provider_gem_cmd) }.and_return('')
+      expect(Puppet::Util::Execution).to receive(:execute).with([provider_gem_cmd, be_an(Array)], be_a(Hash)).and_return('')
       provider.install
     end
 
     it "appends version if given" do
       resource[:ensure] = ['1.2.1']
-      expect(described_class).to receive(:puppetservercmd).with(%w{gem install -v 1.2.1 --no-document myresource}).and_return('')
+      expect(Puppet::Util::Execution).to receive(:execute).with([provider_gem_cmd, %w{gem install -v 1.2.1 --no-document myresource}], anything).and_return('')
       provider.install
     end
 
     context "with install_options" do
       it "does not append the parameter by default" do
-        expect(described_class).to receive(:puppetservercmd).with(%w{gem install --no-document myresource}).and_return('')
+        expect(Puppet::Util::Execution).to receive(:execute).with([provider_gem_cmd, %w{gem install --no-document myresource}], anything).and_return('')
         provider.install
       end
 
       it "allows setting the parameter" do
         resource[:install_options] = [ '--force', {'--bindir' => '/usr/bin' } ]
-        expect(described_class).to receive(:puppetservercmd).with(%w{gem install --force --bindir=/usr/bin --no-document myresource}).and_return('')
+        expect(Puppet::Util::Execution).to receive(:execute).with([provider_gem_cmd, %w{gem install --force --bindir=/usr/bin --no-document myresource}], anything).and_return('')
         provider.install
       end
     end
@@ -54,19 +54,19 @@
     context "with source" do
       it "correctly sets http source" do
         resource[:source] = 'http://rubygems.com'
-        expect(described_class).to receive(:puppetservercmd).with(%w{gem install --no-document --source http://rubygems.com myresource}).and_return('')
+        expect(Puppet::Util::Execution).to receive(:execute).with([provider_gem_cmd, %w{gem install --no-document --source http://rubygems.com myresource}], anything).and_return('')
         provider.install
       end
 
       it "correctly sets local file source" do
         resource[:source] = 'paint-2.2.0.gem'
-        expect(described_class).to receive(:puppetservercmd).with(%w{gem install --no-document paint-2.2.0.gem}).and_return('')
+        expect(Puppet::Util::Execution).to receive(:execute).with([provider_gem_cmd, %w{gem install --no-document paint-2.2.0.gem}], anything).and_return('')
         provider.install
       end
 
       it "correctly sets local file source with URI scheme" do
         resource[:source] = 'file:///root/paint-2.2.0.gem'
-        expect(described_class).to receive(:puppetservercmd).with(%w{gem install --no-document /root/paint-2.2.0.gem}).and_return('')
+        expect(Puppet::Util::Execution).to receive(:execute).with([provider_gem_cmd, %w{gem install --no-document /root/paint-2.2.0.gem}], anything).and_return('')
         provider.install
       end
 
@@ -84,20 +84,19 @@
 
   describe "#uninstall" do
     it "uses the path to the gem command" do
-      allow(described_class).to receive(:validate_command).with(provider_gem_cmd)
-      expect(Puppet::Util::Execution).to receive(:execute).with(be_a(Array), execute_options) { |args| expect(args[0]).to eq(provider_gem_cmd) }.and_return('')
+      expect(Puppet::Util::Execution).to receive(:execute).with([provider_gem_cmd, be_an(Array)], be_a(Hash)).and_return('')
       provider.uninstall
     end
 
     context "with uninstall_options" do
       it "does not append the parameter by default" do
-        expect(described_class).to receive(:puppetservercmd).with(%w{gem uninstall --executables --all myresource}).and_return('')
+        expect(Puppet::Util::Execution).to receive(:execute).with([provider_gem_cmd, %w{gem uninstall --executables --all myresource}], anything).and_return('')
         provider.uninstall
       end
 
       it "allows setting the parameter" do
         resource[:uninstall_options] = [ '--force', {'--bindir' => '/usr/bin' } ]
-        expect(described_class).to receive(:puppetservercmd).with(%w{gem uninstall --executables --all myresource --force --bindir=/usr/bin}).and_return('')
+        expect(Puppet::Util::Execution).to receive(:execute).with([provider_gem_cmd, %w{gem uninstall --executables --all myresource --force --bindir=/usr/bin}], anything).and_return('')
         provider.uninstall
       end
     end
@@ -106,14 +105,17 @@
   describe ".gemlist" do
     context "listing installed packages" do
       it "uses the puppet_gem provider_command to list local gems" do
+        allow(Puppet::Type::Package::ProviderPuppet_gem).to receive(:provider_command).and_return('/opt/puppetlabs/puppet/bin/gem')
+        allow(described_class).to receive(:validate_command).with('/opt/puppetlabs/puppet/bin/gem')
+
         expected = { name: 'world_airports', provider: :puppetserver_gem, ensure: ['1.1.3'] }
-        expect(described_class).to receive(:execute_rubygems_list_command).with(['gem', 'list', '--local']).and_return(File.read(my_fixture('gem-list-local-packages')))
+        expect(Puppet::Util::Execution).to receive(:execute).with(['/opt/puppetlabs/puppet/bin/gem', %w[list --local]], anything).and_return(File.read(my_fixture('gem-list-local-packages')))
         expect(described_class.gemlist({ local: true })).to include(expected)
       end
     end
 
     it "appends the gem source if given" do
-      expect(described_class).to receive(:puppetservercmd).with(%w{gem list --remote --source https://rubygems.com}).and_return('')
+      expect(Puppet::Util::Execution).to receive(:execute).with([provider_gem_cmd, %w{gem list --remote --source https://rubygems.com}], anything).and_return('')
       described_class.gemlist({ source: 'https://rubygems.com' })
     end
   end
diff --git a/spec/unit/util/run_mode_spec.rb b/spec/unit/util/run_mode_spec.rb
index 46a0a55008e..cd7d3f72d6a 100644
--- a/spec/unit/util/run_mode_spec.rb
+++ b/spec/unit/util/run_mode_spec.rb
@@ -97,6 +97,22 @@
         end
       end
     end
+
+    describe "#pkg_config_path" do
+      it { expect(@run_mode.pkg_config_path).to eq('/opt/puppetlabs/puppet/lib/pkgconfig') }
+    end
+
+    describe "#gem_cmd" do
+      it { expect(@run_mode.gem_cmd).to eq('/opt/puppetlabs/puppet/bin/gem') }
+    end
+
+    describe "#common_module_dir" do
+      it { expect(@run_mode.common_module_dir).to eq('/opt/puppetlabs/puppet/modules') }
+    end
+
+    describe "#vendor_module_dir" do
+      it { expect(@run_mode.vendor_module_dir).to eq('/opt/puppetlabs/puppet/vendor_modules') }
+    end
   end
 
   describe Puppet::Util::WindowsRunMode, :if => Puppet::Util::Platform.windows? do
@@ -171,6 +187,81 @@
         end
       end
     end
+
+    describe '#gem_cmd' do
+      before do
+        allow(ENV).to receive(:fetch).and_call_original
+        allow(ENV).to receive(:fetch).with('PUPPET_DIR', nil).and_return(puppetdir)
+      end
+
+      context 'when PUPPET_DIR is not set' do
+        let(:puppetdir) { nil }
+
+        before do
+          allow(Gem).to receive(:default_bindir).and_return('default_gem_bin')
+        end
+
+        it 'uses Gem.default_bindir' do
+          expected_path = File.join('default_gem_bin', 'gem.bat')
+          expect(@run_mode.gem_cmd).to eql(expected_path)
+        end
+      end
+
+      context 'when PUPPET_DIR is set' do
+        let(:puppetdir) { 'puppet_dir' }
+
+        it 'uses Gem.default_bindir' do
+          expected_path = File.join('puppet_dir', 'bin', 'gem.bat')
+          expect(@run_mode.gem_cmd).to eql(expected_path)
+        end
+      end
+    end
+
+    describe '#common_module_dir' do
+      before do
+        allow(ENV).to receive(:fetch).and_call_original
+        allow(ENV).to receive(:fetch).with('FACTER_env_windows_installdir', nil).and_return(installdir)
+      end
+
+      context 'when installdir is not set' do
+        let(:installdir) { nil }
+
+        it 'returns nil' do
+          expect(@run_mode.common_module_dir).to be(nil)
+        end
+      end
+
+      context 'with installdir' do
+        let(:installdir) { 'C:\Program Files\Puppet Labs\Puppet' }
+
+        it 'returns INSTALLDIR/puppet/modules' do
+          expect(@run_mode.common_module_dir).to eq('C:\Program Files\Puppet Labs\Puppet/puppet/modules')
+        end
+      end
+    end
+
+    describe '#vendor_module_dir' do
+      before do
+        allow(ENV).to receive(:fetch).and_call_original
+        allow(ENV).to receive(:fetch).with('FACTER_env_windows_installdir', nil).and_return(installdir)
+      end
+
+      context 'when installdir is not set' do
+        let(:installdir) { nil }
+
+        it 'returns nil' do
+          expect(@run_mode.vendor_module_dir).to be(nil)
+        end
+      end
+
+      context 'with installdir' do
+        let(:installdir) { 'C:\Program Files\Puppet Labs\Puppet' }
+
+        it 'returns INSTALLDIR\puppet\vendor_modules' do
+          expect(@run_mode.vendor_module_dir).to eq('C:\Program Files\Puppet Labs\Puppet\puppet\vendor_modules')
+        end
+      end
+    end
   end
 
   def as_root