diff --git a/spec/spec_helper.rb b/spec/spec_helper.rb
index feb5720..65c6128 100644
--- a/spec/spec_helper.rb
+++ b/spec/spec_helper.rb
@@ -1,54 +1,71 @@
 require 'puppetlabs_spec_helper/module_spec_helper'
 require 'rspec-puppet-facts'
 
 require 'spec_helper_local' if File.file?(File.join(File.dirname(__FILE__), 'spec_helper_local.rb'))
 
 include RspecPuppetFacts
 
 default_facts = {
   puppetversion: Puppet.version,
   facterversion: Facter.version,
 }
 
 default_fact_files = [
   File.expand_path(File.join(File.dirname(__FILE__), 'default_facts.yml')),
   File.expand_path(File.join(File.dirname(__FILE__), 'default_module_facts.yml')),
 ]
 
 default_fact_files.each do |f|
   next unless File.exist?(f) && File.readable?(f) && File.size?(f)
 
   begin
     default_facts.merge!(YAML.safe_load(File.read(f), [], [], true))
   rescue => e
     RSpec.configuration.reporter.message "WARNING: Unable to load #{f}: #{e}"
   end
 end
 
 # read default_facts and merge them over what is provided by facterdb
 default_facts.each do |fact, value|
   add_custom_fact fact, value
 end
 
 RSpec.configure do |c|
   c.default_facts = default_facts
   c.before :each do
     # set to strictest setting for testing
     # by default Puppet runs at warning level
     Puppet.settings[:strict] = :warning
   end
   c.filter_run_excluding(bolt: true) unless ENV['GEM_BOLT']
   c.after(:suite) do
   end
 end
 
 # Ensures that a module is defined
 # @param module_name Name of the module
 def ensure_module_defined(module_name)
   module_name.split('::').reduce(Object) do |last_module, next_module|
     last_module.const_set(next_module, Module.new) unless last_module.const_defined?(next_module, false)
     last_module.const_get(next_module, false)
   end
+
+  c.mock_with :rspec
+  c.before :each do
+    # Ensure that we don't accidentally cache facts and environment between
+    # test cases.  This requires each example group to explicitly load the
+    # facts being exercised with something like
+    # Facter.collection.loader.load(:ipaddress)
+    Facter.clear
+    Facter.clear_messages
+
+    RSpec::Mocks.setup
+  end
+
+  c.after :each do
+    RSpec::Mocks.verify
+    RSpec::Mocks.teardown
+  end
 end
 
 # 'spec_overrides' from sync.yml will appear below this line
diff --git a/spec/unit/puppet/provider/loginctl_user/ruby_spec.rb b/spec/unit/puppet/provider/loginctl_user/ruby_spec.rb
index 03ab8b1..3289254 100644
--- a/spec/unit/puppet/provider/loginctl_user/ruby_spec.rb
+++ b/spec/unit/puppet/provider/loginctl_user/ruby_spec.rb
@@ -1,18 +1,29 @@
 require 'spec_helper'
 require 'puppet'
 
 provider_class = Puppet::Type.type(:loginctl_user).provider(:ruby)
 describe provider_class do
   let(:common_params) do
     {
       title: 'foo',
       linger: 'enabled',
     }
   end
 
+  context 'when listing instances' do
+    it 'should find all entries' do
+      allow(provider_class).to receive(:loginctl).with('list-users', '--no-legend').and_return("0 root\n42 foo\n314 bar\n")
+      allow(provider_class).to receive(:loginctl).with('show-user', '-p', 'Name', '-p', 'Linger', 'root', 'foo', 'bar').and_return("Name=root\nLinger=no\n\nName=foo\nLinger=yes\n\nName=bar\nLinger=no\n")
+      inst = provider_class.instances.map do |p|
+      end
+
+      inst.size.is_expected.to eq(3)
+    end
+  end
+
   context 'when enabling linger' do
     it 'should enable linger' do
       resource = Puppet::Type::LoginctlUser.new(common_params)
     end
   end
 end