Replace mimemagic with marcel (#95)

Mimemagic requires users to download or install additional files.

Rails used Marcel as an abstration layer on this library. Marcel
was updated to another file matching database. Following Rails in
this matter will remove the need for users to do additional work,
just to use caxlsx.

2 files changed, 1 insertions, 3 deletions

diff --git a/test/tc_helper.rb b/test/tc_helper.rb
index 396f19b2..af40a1e4 100644
--- a/test/tc_helper.rb
+++ b/test/tc_helper.rb
@@ -8,5 +8,3 @@ end
 require 'test/unit'
 require "timecop"
 require "axlsx.rb"
-# MIME detection for Microsoft Office 2007+ formats
-require 'mimemagic/overlay'
diff --git a/test/tc_package.rb b/test/tc_package.rb
index d313c2bd..f1ce0421 100644
--- a/test/tc_package.rb
+++ b/test/tc_package.rb
@@ -228,7 +228,7 @@ class TestPackage < Test::Unit::TestCase
   end
 
   def test_serialization_creates_files_with_excel_mime_type
-    assert_equal(MimeMagic.by_magic(@package.to_stream).type,
+    assert_equal(Marcel::MimeType.for(@package.to_stream),
                  'application/vnd.openxmlformats-officedocument.spreadsheetml.sheet')
   end