2 files changed, 90 insertions, 5 deletions

diff --git a/lib/puppet/parser/functions/validate_re.rb b/lib/puppet/parser/functions/validate_re.rb
index 8033ca3..9c216d8 100644
--- a/lib/puppet/parser/functions/validate_re.rb
+++ b/lib/puppet/parser/functions/validate_re.rb
@@ -1,5 +1,4 @@
 module Puppet::Parser::Functions
-
   newfunction(:validate_re, :doc => <<-'ENDHEREDOC') do |args|
     Perform simple validation of a string against one or more regular
     expressions. The first argument of this function should be a string to
@@ -8,6 +7,9 @@ module Puppet::Parser::Functions
     of the regular expressions match the string passed in, compilation will
     abort with a parse error.
 
+    If a third argument is specified, this will be the error message raised and
+    seen by the user.
+
     The following strings will validate against the regular expressions:
 
         validate_re('one', '^one$')
@@ -17,17 +19,20 @@ module Puppet::Parser::Functions
 
         validate_re('one', [ '^two', '^three' ])
 
+    A helpful error message can be returned like this:
+
+        validate_re($::puppetversion, '^2.7', 'The $puppetversion fact value does not match 2.7')
+
     ENDHEREDOC
-    if args.length != 2 then
-      raise Puppet::ParseError, ("validate_re(): wrong number of arguments (#{args.length}; must be 2)")
+    if (args.length < 2) or (args.length > 3) then
+      raise Puppet::ParseError, ("validate_re(): wrong number of arguments (#{args.length}; must be 2 or 3)")
     end
 
-    msg = "validate_re(): #{args[0].inspect} does not match #{args[1].inspect}"
+    msg = args[2] || "validate_re(): #{args[0].inspect} does not match #{args[1].inspect}"
 
     raise Puppet::ParseError, (msg) unless args[1].any? do |re_str|
       args[0] =~ Regexp.compile(re_str)
     end
 
   end
-
 end
diff --git a/spec/unit/puppet/parser/functions/validate_re_spec.rb b/spec/unit/puppet/parser/functions/validate_re_spec.rb
new file mode 100644
index 0000000..c35ae14
--- /dev/null
+++ b/spec/unit/puppet/parser/functions/validate_re_spec.rb
@@ -0,0 +1,80 @@
+require 'spec_helper'
+
+describe Puppet::Parser::Functions.function(:validate_re) do
+  before :all do
+    Puppet::Parser::Functions.autoloader.loadall
+  end
+
+  let(:scope) do
+    scope = Puppet::Parser::Scope.new
+  end
+
+  # The subject of these examplres is the method itself.
+  subject do
+    scope.method :function_validate_re
+  end
+
+  context 'Using Puppet::Parser::Scope.new' do
+
+    describe 'Garbage inputs' do
+      inputs = [
+        [ nil ],
+        [ [ nil ] ],
+        [ { 'foo' => 'bar' } ],
+        [ { } ],
+        [ '' ],
+        [ "one", "one", "MSG to User", "4th arg" ],
+      ]
+
+      inputs.each do |input|
+        it "validate_re(#{input.inspect}) should fail" do
+          expect { subject.call [input] }.to raise_error Puppet::ParseError
+        end
+      end
+    end
+
+    describe 'Valid inputs' do
+      inputs = [
+        [ '/full/path/to/something', '^/full' ],
+        [ '/full/path/to/something', 'full' ],
+        [ '/full/path/to/something', ['full', 'absent'] ],
+        [ '/full/path/to/something', ['full', 'absent'], 'Message to the user' ],
+      ]
+
+      inputs.each do |input|
+        it "validate_re(#{input.inspect}) should not fail" do
+          expect { subject.call input }.not_to raise_error
+        end
+      end
+    end
+    describe "Valid inputs which should raise an exception without a message" do
+      # The intent here is to make sure valid inputs raise exceptions when they
+      # don't specify an error message to display.  This is the behvior in
+      # 2.2.x and prior.
+      inputs = [
+        [ "hello", [ "bye", "later", "adios" ] ],
+        [ "greetings", "salutations" ],
+      ]
+
+      inputs.each do |input|
+        it "validate_re(#{input.inspect}) should fail" do
+          expect { subject.call input }.to raise_error /validate_re.*?does not match/
+        end
+      end
+    end
+    describe "Nicer Error Messages" do
+      # The intent here is to make sure the function returns the 3rd argument
+      # in the exception thrown
+      inputs = [
+        [ "hello", [ "bye", "later", "adios" ], "MSG to User" ],
+        [ "greetings", "salutations", "Error, greetings does not match salutations" ],
+      ]
+
+      inputs.each do |input|
+        it "validate_re(#{input.inspect}) should fail" do
+          expect { subject.call input }.to raise_error /#{input[2]}/
+        end
+      end
+    end
+  end
+end