(antonlindstrom#15) Improve error message on failure

Author: ju5t

manifests/config.pp

@@ -6,7 +6,7 @@
   $type    = 'authoritative'
 ) {
 
-  if $value == '' and ! ($setting in [ 'gmysql-dnssec', 'only-notify' ]) { fail("Value can't be empty.") }
+  if $value == '' and ! ($setting in [ 'gmysql-dnssec', 'only-notify' ]) { fail("Value for ${setting} can't be empty.") }
   if $setting == 'gmysql-dnssec' { $line = $setting }
   else { $line = "${setting}=${value}" }
 

spec/defines/powerdns_config_spec.rb

@@ -99,7 +99,7 @@
           end
 
           it 'fails' do
-            expect { subject.call } .to raise_error(/Value can't be empty./)
+            expect { subject.call } .to raise_error(/Value for empty can't be empty./)
           end
         end