Add Blob#file_type convenience method

app/models/blob.rb

@@ -155,6 +155,10 @@ class Blob < SimpleDelegator
     @extension ||= extname.downcase.delete('.')
   end
 
+  def file_type
+    Gitlab::FileDetector.type_of(path)
+  end
+
   def video?
     UploaderHelper::VIDEO_EXT.include?(extension)
   end

app/models/blob_viewer/base.rb

@@ -52,7 +52,7 @@ module BlobViewer
     def self.can_render?(blob, verify_binary: true)
       return false if verify_binary && binary? != blob.binary?
       return true if extensions&.include?(blob.extension)
-      return true if file_types&.include?(Gitlab::FileDetector.type_of(blob.path))
+      return true if file_types&.include?(blob.file_type)
 
       false
     end

spec/models/blob_spec.rb

@@ -199,6 +199,14 @@ describe Blob do
     end
   end
 
+  describe '#file_type' do
+    it 'returns the file type' do
+      blob = fake_blob(path: 'README.md')
+
+      expect(blob.file_type).to eq(:readme)
+    end
+  end
+
   describe '#simple_viewer' do
     context 'when the blob is empty' do
       it 'returns an empty viewer' do