(#13610) Add is_function_available to stdlib

This function provides a simple wrapper around
Puppet::Parser::Functions.function for access within Puppet manifests.
This will allow users to check whether or not a plugin or functionality
such as hiera is installed on the server.

1 files changed, 31 insertions, 0 deletions

diff --git a/spec/unit/puppet/parser/functions/is_function_available.rb b/spec/unit/puppet/parser/functions/is_function_available.rb
new file mode 100644
index 0000000..bd40c51
--- /dev/null
+++ b/spec/unit/puppet/parser/functions/is_function_available.rb
@@ -0,0 +1,31 @@
+#!/usr/bin/env rspec
+require 'spec_helper'
+
+describe "the is_function_available function" do
+  before :all do
+    Puppet::Parser::Functions.autoloader.loadall
+  end
+
+  before :each do
+    @scope = Puppet::Parser::Scope.new
+  end
+
+  it "should exist" do
+    Puppet::Parser::Functions.function("is_function_available").should == "function_is_function_available"
+  end
+
+  it "should raise a ParseError if there is less than 1 arguments" do
+    lambda { @scope.function_is_function_available([]) }.should( raise_error(Puppet::ParseError))
+  end
+
+  it "should return false if a nonexistent function is passed" do
+    result = @scope.function_is_function_available(['jeff_mccunes_left_sock'])
+    result.should(eq(false))
+  end
+
+  it "should return true if an available function is passed" do
+    result = @scope.function_is_function_available(['require'])
+    result.should(eq(true))
+  end
+
+end