Allow i18n key for include_blank and prompt

lib/simple_form/inputs/collection_input.rb

@@ -23,7 +23,7 @@ module SimpleForm
         options[:include_blank] = true unless skip_include_blank?
 
         [:prompt, :include_blank].each do |key|
-          options[key] = translate(key, true) if options[key] == :translate
+          translate_option options, key
         end
 
         options
@@ -101,6 +101,16 @@ module SimpleForm
           true
         end
       end
+
+      def translate_option(options, key)
+        return unless options[key].is_a? Symbol
+
+        options[key] = if options[key] == :translate
+          translate(key, true)
+        else
+          I18n.t(options[key], scope: :"simple_form.#{key}")
+        end
+      end
     end
   end
 end

test/inputs/collection_select_input_test.rb

@@ -105,6 +105,16 @@ class CollectionSelectInputTest < ActionView::TestCase
     end
   end
 
+  test 'input should translate include blank with a particular key' do
+    store_translations(:en, :simple_form => { :include_blank => {
+      :age => 'Rather not say',
+      :user => { :age => 'Should be overridden' }
+    } } ) do
+      with_input_for @user, :age, :select, :collection => 18..30, :include_blank => :age
+      assert_select 'select option[value=]', 'Rather not say'
+    end
+  end
+
   test 'input should not translate include blank when set to a string' do
     store_translations(:en, :simple_form => { :include_blank => { :user => {
       :age => 'Rather not say'
@@ -165,6 +175,16 @@ class CollectionSelectInputTest < ActionView::TestCase
     end
   end
 
+  test 'input should translate prompt with a particular key' do
+    store_translations(:en, :simple_form => { :prompt => {
+      :age => 'Select age:',
+      :user => { :age => 'Should be overridden' }
+    } } ) do
+      with_input_for @user, :age, :select, :collection => 18..30, :prompt => :age
+      assert_select 'select option[value=]', 'Select age:'
+    end
+  end
+
   test 'input should not translate prompt when set to a string' do
     store_translations(:en, :simple_form => { :prompt => { :user => {
       :age => 'Select age:'