Merge branch 'pull-56'

lib/puppet/parser/functions/range.rb

@@ -27,6 +27,13 @@ Will return: ["a","b","c"]
     range("host01", "host10")
 
 Will return: ["host01", "host02", ..., "host09", "host10"]
+
+Passing a third argument will cause the generated range to step by that 
+interval, e.g.
+
+    range("0", "9", "2")
+
+Will return: [0,2,4,6,8]
     EOS
   ) do |arguments|
 
@@ -37,6 +44,7 @@ Will return: ["host01", "host02", ..., "host09", "host10"]
     if arguments.size > 1
       start = arguments[0]
       stop  = arguments[1]
+      step  = arguments[2].nil? ? 1 : arguments[2].to_i.abs
 
       type = '..' # We select simplest type for Range available in Ruby ...
 
@@ -71,7 +79,7 @@ Will return: ["host01", "host02", ..., "host09", "host10"]
         when /^(\.\.\.)$/  then (start ... stop) # Exclusive of last element ...
       end
 
-      result = range.collect { |i| i } # Get them all ... Pokemon ...
+      result = range.step(step).collect { |i| i } # Get them all ... Pokemon ...
 
     return result
   end

spec/unit/puppet/parser/functions/range_spec.rb

@@ -4,31 +4,67 @@ require 'spec_helper'
 describe "the range function" do
   let(:scope) { PuppetlabsSpec::PuppetInternals.scope }
 
-  it "should exist" do
+  it "exists" do
     Puppet::Parser::Functions.function("range").should == "function_range"
   end
 
-  it "should raise a ParseError if there is less than 1 arguments" do
+  it "raises a ParseError if there is less than 1 arguments" do
-    lambda { scope.function_range([]) }.should( raise_error(Puppet::ParseError))
+    expect { scope.function_range([]) }.to raise_error Puppet::ParseError, /Wrong number of arguments.*0 for 1/
   end
 
-  it "should return a letter range" do
+  describe 'with a letter range' do
+    it "returns a letter range" do
       result = scope.function_range(["a","d"])
-    result.should(eq(['a','b','c','d']))
+      result.should eq ['a','b','c','d']
     end
 
-  it "should return a number range" do
+    it "returns a letter range given a step of 1" do
+      result = scope.function_range(["a","d","1"])
+      result.should eq ['a','b','c','d']
+    end
+
+    it "returns a stepped letter range" do
+      result = scope.function_range(["a","d","2"])
+      result.should eq ['a','c']
+    end
+
+    it "returns a stepped letter range given a negative step" do
+      result = scope.function_range(["a","d","-2"])
+      result.should eq ['a','c']
+    end
+  end
+
+  describe 'with a number range' do
+    it "returns a number range" do
       result = scope.function_range(["1","4"])
-    result.should(eq([1,2,3,4]))
+      result.should eq [1,2,3,4]
     end
 
-  it "should work with padded hostname like strings" do
+    it "returns a number range given a step of 1" do
+      result = scope.function_range(["1","4","1"])
+      result.should eq [1,2,3,4]
+    end
+
+    it "returns a stepped number range" do
+      result = scope.function_range(["1","4","2"])
+      result.should eq [1,3]
+    end
+
+    it "returns a stepped number range given a negative step" do
+      result = scope.function_range(["1","4","-2"])
+      result.should eq [1,3]
+    end
+  end
+
+  describe 'with a numeric-like string range' do
+    it "works with padded hostname like strings" do
       expected = ("host01".."host10").to_a
       scope.function_range(["host01","host10"]).should eq expected
     end
 
-  it "should coerce zero padded digits to integers" do
+    it "coerces zero padded digits to integers" do
       expected = (0..10).to_a
       scope.function_range(["00", "10"]).should eq expected
     end
+  end
 end