diff --git a/manifests/config.pp b/manifests/config.pp
index 564fc8f2d..4b60e32e6 100644
--- a/manifests/config.pp
+++ b/manifests/config.pp
@@ -13,9 +13,7 @@
 #
 class icinga2::config {
 
-  if defined($caller_module_name) and $module_name != $caller_module_name {
-    fail("icinga2::config is a private class of the module icinga2, you're not permitted to use it.")
-  }
+  assert_private()
 
   $constants      = prefix($::icinga2::_constants, 'const ')
   $conf_dir       = $::icinga2::params::conf_dir
diff --git a/manifests/debian/dbconfig.pp b/manifests/debian/dbconfig.pp
index 24ab14fc1..99cb81f17 100644
--- a/manifests/debian/dbconfig.pp
+++ b/manifests/debian/dbconfig.pp
@@ -8,9 +8,7 @@
   $ssl = false,
 ) {
 
-  if defined($caller_module_name) and $module_name != $caller_module_name and $caller_module_name != '' {
-    fail("icinga2::debian::dbconfig is a private define resource of the module icinga2, you're not permitted to use it.")
-  }
+  assert_private()
 
   validate_re($dbtype, [ '^mysql$', '^pgsql$' ],
     "${dbtype} isn't supported. Valid values are 'mysql' and 'pgsql'.")
diff --git a/manifests/feature.pp b/manifests/feature.pp
index b50ec2afa..d886d2649 100644
--- a/manifests/feature.pp
+++ b/manifests/feature.pp
@@ -8,13 +8,7 @@
   $feature = $title,
 ) {
 
-  if defined($caller_module_name) and $module_name != $caller_module_name and $caller_module_name != '' {
-    fail("icinga2::feature is a private define resource of the module icinga2, you're not permitted to use it.")
-  }
-
-  if ! defined(Class['::icinga2']) {
-    fail('You must include the icinga2 base class before using any icinga2 feature class!')
-  }
+  assert_private()
 
   validate_re($ensure, [ '^present$', '^absent$' ],
     "${ensure} isn't supported. Valid values are 'present' and 'absent'.")
diff --git a/manifests/install.pp b/manifests/install.pp
index 3d0c9d278..71c057394 100644
--- a/manifests/install.pp
+++ b/manifests/install.pp
@@ -14,9 +14,7 @@
 #
 class icinga2::install {
 
-  if defined($caller_module_name) and $module_name != $caller_module_name {
-    fail("icinga2::install is a private class of the module icinga2, you're not permitted to use it.")
-  }
+  assert_private()
 
   $package        = $::icinga2::params::package
   $conf_dir       = $::icinga2::params::conf_dir
diff --git a/manifests/object.pp b/manifests/object.pp
index 6c356de3c..8fced1297 100644
--- a/manifests/object.pp
+++ b/manifests/object.pp
@@ -77,9 +77,7 @@
   $attrs        = {},
 ) {
 
-  if defined($caller_module_name) and $module_name != $caller_module_name and $caller_module_name != '' {
-    fail("icinga2::object is a private define resource of the module icinga2, you're not permitted to use it.")
-  }
+  assert_private()
 
   include ::icinga2::params
 
diff --git a/manifests/repo.pp b/manifests/repo.pp
index 4fd01a86c..897e445b8 100644
--- a/manifests/repo.pp
+++ b/manifests/repo.pp
@@ -16,9 +16,7 @@
 #
 class icinga2::repo {
 
-  if defined($caller_module_name) and $module_name != $caller_module_name {
-    fail("icinga2::repo is a private class of the module icinga2, you're not permitted to use it.")
-  }
+  assert_private()
 
   if $::icinga2::manage_repo and $::icinga2::manage_package {
 
diff --git a/manifests/service.pp b/manifests/service.pp
index 04c664b2b..b06c542dd 100644
--- a/manifests/service.pp
+++ b/manifests/service.pp
@@ -16,9 +16,7 @@
 #
 class icinga2::service {
 
-  if defined($caller_module_name) and $module_name != $caller_module_name {
-    fail("icinga2::service is a private class of the module icinga2, you're not permitted to use it.")
-  }
+  assert_private()
 
   $ensure         = $::icinga2::ensure
   $enable         = $::icinga2::enable
diff --git a/spec/spec_helper.rb b/spec/spec_helper.rb
index fda28e6bc..70db1fba0 100644
--- a/spec/spec_helper.rb
+++ b/spec/spec_helper.rb
@@ -10,4 +10,9 @@
   default_facts.merge!(YAML.load(File.read(File.expand_path('../default_facts.yml', __FILE__)))) if File.exist?(File.expand_path('../default_facts.yml', __FILE__))
   default_facts.merge!(YAML.load(File.read(File.expand_path('../default_module_facts.yml', __FILE__)))) if File.exist?(File.expand_path('../default_module_facts.yml', __FILE__))
   c.default_facts = default_facts
+
+  c.before(:each) do
+    # Stub assert_private function from stdlib to not fail within this test
+    Puppet::Parser::Functions.newfunction(:assert_private) { |_| }
+  end
 end