diff --git a/lib/linguist/blob_helper.rb b/lib/linguist/blob_helper.rb
index 09d1bf3d..75bee673 100644
--- a/lib/linguist/blob_helper.rb
+++ b/lib/linguist/blob_helper.rb
@@ -32,7 +32,10 @@ module Linguist
     #
     # Returns a mime type String.
     def mime_type
-      @mime_type ||= Mime.mime_for(extname.to_s)
+      @mime_type ||= begin
+        mime_type = Mime.lookup_mime_type_for(extname.to_s)
+        mime_type ? mime_type.to_s : 'text/plain'
+      end
     end
 
     # Public: Get the Content-Type header value
diff --git a/lib/linguist/mime.rb b/lib/linguist/mime.rb
index 59f30ada..a1e5555f 100644
--- a/lib/linguist/mime.rb
+++ b/lib/linguist/mime.rb
@@ -3,24 +3,6 @@ require 'yaml'
 
 module Linguist
   module Mime
-    # Internal: Look up mime type for extension.
-    #
-    # ext - The extension String. May include leading "."
-    #
-    # Examples
-    #
-    #   Mime.mime_for('.html')
-    #   # => 'text/html'
-    #
-    #   Mime.mime_for('txt')
-    #   # => 'text/plain'
-    #
-    # Return mime type String otherwise falls back to 'text/plain'.
-    def self.mime_for(ext)
-      mime_type = lookup_mime_type_for(ext)
-      mime_type ? mime_type.to_s : 'text/plain'
-    end
-
     # Internal: Lookup mime type for extension or mime type
     #
     # ext_or_mime_type - A file extension ".txt" or mime type "text/plain".
diff --git a/test/test_mime.rb b/test/test_mime.rb
deleted file mode 100644
index 81c212ec..00000000
--- a/test/test_mime.rb
+++ /dev/null
@@ -1,48 +0,0 @@
-require 'linguist/mime'
-
-require 'test/unit'
-
-class TestMime < Test::Unit::TestCase
-  include Linguist
-
-  def test_extension_lookup
-    # Default to plain text if we have no idea.
-    assert_equal 'text/plain', Mime.mime_for(nil)
-    assert_equal 'text/plain', Mime.mime_for('')
-
-    # Add an assertion to this list if you add/change any extensions
-    # in mimes.yml. Its still useful to test even trivial cases since
-    # MIME::Type's extension lookup may return multiple matches and we
-    # only pick one of them. Please keep this list alphabetized.
-    assert_equal 'application/javascript', Mime.mime_for('.js')
-    assert_equal 'application/octet-stream', Mime.mime_for('.dll')
-    assert_equal 'application/octet-stream', Mime.mime_for('.dmg')
-    assert_equal 'application/octet-stream', Mime.mime_for('.exe')
-    assert_equal 'application/postscript', Mime.mime_for('.ai')
-    assert_equal 'application/postscript', Mime.mime_for('.eps')
-    assert_equal 'application/postscript', Mime.mime_for('.ps')
-    assert_equal 'application/vnd.adobe.air-application-installer-package+zip', Mime.mime_for('.air')
-    assert_equal 'application/vnd.oasis.opendocument.presentation', Mime.mime_for('.odp')
-    assert_equal 'application/vnd.oasis.opendocument.spreadsheet', Mime.mime_for('.ods')
-    assert_equal 'application/vnd.oasis.opendocument.text', Mime.mime_for('.odt')
-    assert_equal 'application/vnd.openxmlformats-officedocument.presentationml.presentation', Mime.mime_for('.pptx')
-    assert_equal 'application/x-debian-package', Mime.mime_for('.deb')
-    assert_equal 'application/x-latex', Mime.mime_for('.latex')
-    assert_equal 'application/x-perl', Mime.mime_for('.pl')
-    assert_equal 'application/x-perl', Mime.mime_for('.pm')
-    assert_equal 'application/x-python', Mime.mime_for('.py')
-    assert_equal 'application/x-ruby', Mime.mime_for('.rb')
-    assert_equal 'application/x-sh', Mime.mime_for('.sh')
-    assert_equal 'application/x-shockwave-flash', Mime.mime_for('.swf')
-    assert_equal 'text/html', Mime.mime_for('.html')
-    assert_equal 'text/plain', Mime.mime_for('.c')
-    assert_equal 'text/plain', Mime.mime_for('.cc')
-    assert_equal 'text/plain', Mime.mime_for('.cpp')
-    assert_equal 'text/plain', Mime.mime_for('.cxx')
-    assert_equal 'text/plain', Mime.mime_for('.h')
-    assert_equal 'text/plain', Mime.mime_for('.hh')
-    assert_equal 'text/plain', Mime.mime_for('.hpp')
-    assert_equal 'text/plain', Mime.mime_for('.kt')
-    assert_equal 'video/quicktime', Mime.mime_for('.mov')
-  end
-end