1 files changed, 19 insertions, 0 deletions
diff --git a/spec/unit/puppet/parser/functions/difference_spec.rb b/spec/unit/puppet/parser/functions/difference_spec.rb
new file mode 100644
index 0000000..9feff09
--- /dev/null
+++ b/spec/unit/puppet/parser/functions/difference_spec.rb
@@ -0,0 +1,19 @@
+#! /usr/bin/env ruby -S rspec
+require 'spec_helper'
+
+describe "the difference function" do
+  let(:scope) { PuppetlabsSpec::PuppetInternals.scope }
+
+  it "should exist" do
+    Puppet::Parser::Functions.function("difference").should == "function_difference"
+  end
+
+  it "should raise a ParseError if there are fewer than 2 arguments" do
+    lambda { scope.function_difference([]) }.should( raise_error(Puppet::ParseError) )
+  end
+
+  it "should return the difference between two arrays" do
+    result = scope.function_difference([["a","b","c"],["b","c","d"]])
+    result.should(eq(["a"]))
+  end
+end