--- a/modules/stdlib/spec/functions/flatten_spec.rb	Tue Dec 31 13:49:38 2019 +0000
+++ b/modules/stdlib/spec/functions/flatten_spec.rb	Fri Jan 03 19:56:04 2020 +0000
@@ -1,27 +1,15 @@
-#! /usr/bin/env ruby -S rspec
 require 'spec_helper'
 
-describe "the flatten function" do
-  let(:scope) { PuppetlabsSpec::PuppetInternals.scope }
-  it "should exist" do
-    expect(Puppet::Parser::Functions.function("flatten")).to eq("function_flatten")
-  end
-
-  it "should raise a ParseError if there is less than 1 arguments" do
-    expect { scope.function_flatten([]) }.to( raise_error(Puppet::ParseError))
-  end
-
-  it "should raise a ParseError if there is more than 1 argument" do
-    expect { scope.function_flatten([[], []]) }.to( raise_error(Puppet::ParseError))
-  end
-
-  it "should flatten a complex data structure" do
-    result = scope.function_flatten([["a","b",["c",["d","e"],"f","g"]]])
-    expect(result).to(eq(["a","b","c","d","e","f","g"]))
-  end
-
-  it "should do nothing to a structure that is already flat" do
-    result = scope.function_flatten([["a","b","c","d"]])
-    expect(result).to(eq(["a","b","c","d"]))
-  end
+describe 'flatten', :if => Puppet::Util::Package.versioncmp(Puppet.version, '5.5.0') < 0 do
+  it { is_expected.not_to eq(nil) }
+  it { is_expected.to run.with_params.and_raise_error(Puppet::ParseError) }
+  it { is_expected.to run.with_params([], []).and_raise_error(Puppet::ParseError) }
+  it { is_expected.to run.with_params(1).and_raise_error(Puppet::ParseError) }
+  it { is_expected.to run.with_params('one').and_raise_error(Puppet::ParseError) }
+  it { is_expected.to run.with_params([]).and_return([]) }
+  it { is_expected.to run.with_params(['one']).and_return(['one']) }
+  it { is_expected.to run.with_params([['one']]).and_return(['one']) }
+  it { is_expected.to run.with_params(%w[a b c d e f g]).and_return(%w[a b c d e f g]) }
+  it { is_expected.to run.with_params([['a', 'b', ['c', %w[d e], 'f', 'g']]]).and_return(%w[a b c d e f g]) }
+  it { is_expected.to run.with_params(['ã', 'β', ['ĉ', %w[đ ẽ ƒ ġ]]]).and_return(%w[ã β ĉ đ ẽ ƒ ġ]) }
 end