Fixed Gollum pages link url expansion to render correctly in preview

lib/banzai/filter/gollum_tags_filter.rb

@@ -144,12 +144,18 @@ module Banzai
       # if it is not.
       def process_page_link_tag(parts)
         if parts.size == 1
-          url = parts[0].strip
+          reference = parts[0].strip
         else
-          name, url = *parts.compact.map(&:strip)
+          name, reference = *parts.compact.map(&:strip)
         end
 
-        content_tag(:a, name || url, href: url)
+        if url?(reference)
+          href = reference
+        else
+          href = ::File.join(project_wiki_base_path, reference)
+        end
+
+        content_tag(:a, name || reference, href: href)
       end
 
       def project_wiki

spec/lib/banzai/filter/gollum_tags_filter_spec.rb

@@ -70,20 +70,22 @@ describe Banzai::Filter::GollumTagsFilter, lib: true do
   end
 
   context 'linking internal resources' do
-    it "the created link's text will be equal to the resource's text" do
+    it "the created link's text will include the resource's text and project_wiki_base_path" do
       tag = '[[wiki-slug]]'
       doc = filter("See #{tag}", project_wiki: project_wiki)
+      expected_path = ::File.join(project_wiki.wiki_base_path, 'wiki-slug')
 
       expect(doc.at_css('a').text).to eq 'wiki-slug'
-      expect(doc.at_css('a')['href']).to eq 'wiki-slug'
+      expect(doc.at_css('a')['href']).to eq expected_path
     end
 
     it "the created link's text will be link-text" do
       tag = '[[link-text|wiki-slug]]'
       doc = filter("See #{tag}", project_wiki: project_wiki)
+      expected_path = ::File.join(project_wiki.wiki_base_path, 'wiki-slug')
 
       expect(doc.at_css('a').text).to eq 'link-text'
-      expect(doc.at_css('a')['href']).to eq 'wiki-slug'
+      expect(doc.at_css('a')['href']).to eq expected_path
     end
   end