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, 8 insertions, 26 deletions

diff --git a/spec/functions/is_hash_spec.rb b/spec/functions/is_hash_spec.rb
index a849411..c2599a0 100755
--- a/spec/functions/is_hash_spec.rb
+++ b/spec/functions/is_hash_spec.rb
@@ -1,29 +1,11 @@
-#! /usr/bin/env ruby -S rspec
 require 'spec_helper'
 
-describe "the is_hash function" do
-  let(:scope) { PuppetlabsSpec::PuppetInternals.scope }
-
-  it "should exist" do
-    expect(Puppet::Parser::Functions.function("is_hash")).to eq("function_is_hash")
-  end
-
-  it "should raise a ParseError if there is less than 1 arguments" do
-    expect { scope.function_is_hash([]) }.to( raise_error(Puppet::ParseError))
-  end
-
-  it "should return true if passed a hash" do
-    result = scope.function_is_hash([{"a"=>1,"b"=>2}])
-    expect(result).to(eq(true))
-  end
-
-  it "should return false if passed an array" do
-    result = scope.function_is_hash([["a","b"]])
-    expect(result).to(eq(false))
-  end
-
-  it "should return false if passed a string" do
-    result = scope.function_is_hash(["asdf"])
-    expect(result).to(eq(false))
-  end
+describe 'is_hash' 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('').and_return(false) }
+  it { is_expected.to run.with_params({}).and_return(true) }
+  it { is_expected.to run.with_params([]).and_return(false) }
+  it { is_expected.to run.with_params(1).and_return(false) }
 end