Warn on conf when an option is not recognized

spec/conf_spec.rb

@@ -4,17 +4,17 @@ require 'spec_helper'
 describe Squib::Conf do
 
   it 'parses the project template file just fine' do
-    conf = Squib::Conf.load(project_template('config.yml'))
+    conf = Squib::Conf.load project_template('config.yml')
     expect(conf.backend).to eq(Squib::Conf::DEFAULTS['backend'])
   end
 
   it 'parses an empty file' do
-    conf = Squib::Conf.load(conf('empty.yml'))
+    conf = Squib::Conf.load conf('empty.yml')
     expect(conf.backend).to eq(Squib::Conf::DEFAULTS['backend'])
   end
 
   it 'parses the sample custom config' do
-    conf = Squib::Conf.load(sample_file('custom-config.yml'))
+    conf = Squib::Conf.load sample_file('custom-config.yml')
     expect(conf.progress_bars).to  be true
     expect(conf.text_hint).to      eq '#FF0000'
     expect(conf.custom_colors).to  eq({ 'foo' => '#ccc' })
@@ -26,4 +26,9 @@ describe Squib::Conf do
     expect(Squib::Conf.new.antialias).to          eq 'subpixel'
   end
 
+  it 'warns when the yml has an unrecognized option' do
+    expect(Squib::logger).to receive(:warn).with('Unrecognized configuration option(s): unicorns')
+    Squib::Conf.load conf('unrecognized.yml')
+  end
+
 end

spec/data/conf/unrecognized.yml

@@ -0,0 +1,4 @@
+# This is recognized, so it should be fine.
+backend: svg
+# This is not recognized.
+unicorns: true