Usability: Don't raise an exception when config is missing or invalid

features/plugin.feature

@@ -0,0 +1,12 @@
+Feature: General plugin usage
+  Scenario: No config at all
+    Given I have no configuration
+    When I run Jekyll
+    Then there should be no errors
+
+  Scenario: Config with empty responsive_image block
+    Given I have a responsive_image configuration with:
+      """
+      """
+    When I run Jekyll
+    Then there should be no errors

features/step_definitions/jekyll_steps.rb

@@ -6,6 +6,10 @@ Then /^Jekyll should throw a "(.+)"$/ do |error_class|
   assert_raise(Object.const_get(error_class)) { run_jekyll }
 end
 
+Then /^there should be no errors$/ do
+  # Implicit pass
+end
+
 Given /^I have copied my site to "(.+)"$/ do |path|
   new_site_dir = File.join(TEST_DIR, path)
 
@@ -16,6 +20,10 @@ Given /^I have copied my site to "(.+)"$/ do |path|
     .each { |f| FileUtils.mv(f, new_site_dir) }
 end
 
+Given /^I have no configuration$/ do
+  write_file('_config.yml', '')
+end
+
 Given /^I have a configuration with:$/ do |config|
   write_file('_config.yml', config)
 end

lib/jekyll-responsive-image/config.rb

@@ -17,8 +17,19 @@ module Jekyll
         @site = site
       end
 
+      def valid_config(config)
+        config.has_key?('responsive_image') && config['responsive_image'].is_a?(Hash)
+      end
+
       def to_h
-        DEFAULTS.merge(@site.config['responsive_image'])
+        config = {}
+
+        if valid_config(@site.config)
+          config = @site.config['responsive_image']
+        end
+
+
+        DEFAULTS.merge(config)
                 .merge(site_source: @site.source, site_dest: @site.dest)
       end
     end

lib/jekyll-responsive-image/version.rb

@@ -1,5 +1,5 @@
 module Jekyll
   module ResponsiveImage
-    VERSION = '1.5.1'.freeze
+    VERSION = '1.5.2'.freeze
   end
 end