Add tests for large image Twitter card

lib/template.html

@@ -132,13 +132,12 @@
 {% endif %}
 
 {% if site.twitter %}
-
-  {% if page.image %}
+  {% if seo_page_image %}
     <meta name="twitter:card" content="summary_large_image" />
   {% else %}
     <meta name="twitter:card" content="summary" />
   {% endif %}
-  
+
   <meta name="twitter:site" content="@{{ site.twitter.username | replace:"@","" }}" />
 
   {% if seo_author_twitter %}

spec/jekyll_seo_tag_spec.rb

@@ -203,6 +203,9 @@ EOS
         let(:page) { make_page('author' => 'benbalter') }
 
         it 'outputs twitter card meta' do
+          expected = %r{<meta name="twitter:card" content="summary" />}
+          expect(output).to match(expected)
+
           expected = %r{<meta name="twitter:site" content="@jekyllrb" />}
           expect(output).to match(expected)
 
@@ -241,6 +244,15 @@ EOS
         end
       end
 
+      context 'with page.image' do
+        let(:page) { make_page('image' => '/img/foo.png') }
+
+        it 'outputs summary card with large image' do
+          expected = %r{<meta name="twitter:card" content="summary_large_image" />}
+          expect(output).to match(expected)
+        end
+      end
+
       context 'with page.author as a hash' do
         let(:page) { make_page('author' => { 'twitter' => '@test' }) }