Convert tests to use plain rspec-puppet

Tests in the new style produces the following documentation output:

abs
  should not eq nil
  should run abs() and raise an Puppet::ParseError
  should run abs(-34) and return 34
  should run abs("-34") and return 34
  should run abs(34) and return 34
  should run abs("34") and return 34

1 files changed, 6 insertions, 19 deletions

diff --git a/spec/functions/parsejson_spec.rb b/spec/functions/parsejson_spec.rb
index 1dd41b9..436566e 100755
--- a/spec/functions/parsejson_spec.rb
+++ b/spec/functions/parsejson_spec.rb
@@ -1,22 +1,9 @@
-#! /usr/bin/env ruby -S rspec
 require 'spec_helper'
 
-describe "the parsejson function" do
-  let(:scope) { PuppetlabsSpec::PuppetInternals.scope }
-
-  it "should exist" do
-    expect(Puppet::Parser::Functions.function("parsejson")).to eq("function_parsejson")
-  end
-
-  it "should raise a ParseError if there is less than 1 arguments" do
-    expect { scope.function_parsejson([]) }.to( raise_error(Puppet::ParseError))
-  end
-
-  it "should convert JSON to a data structure" do
-    json = <<-EOS
-["aaa","bbb","ccc"]
-EOS
-    result = scope.function_parsejson([json])
-    expect(result).to(eq(['aaa','bbb','ccc']))
-  end
+describe 'parsejson' do
+  it { is_expected.not_to eq(nil) }
+  it { is_expected.to run.with_params().and_raise_error(Puppet::ParseError, /wrong number of arguments/i) }
+  it { is_expected.to run.with_params('', '').and_raise_error(Puppet::ParseError, /wrong number of arguments/i) }
+  it { is_expected.to run.with_params('["one"').and_raise_error(PSON::ParserError) }
+  it { is_expected.to run.with_params('["one", "two", "three"]').and_return(['one', 'two', 'three']) }
 end