Sort archive entries for correct MIME detection with file command

2 files changed, 9 insertions, 3 deletions

diff --git a/lib/axlsx/package.rb b/lib/axlsx/package.rb
index 1b30c815..2faec2e3 100644
--- a/lib/axlsx/package.rb
+++ b/lib/axlsx/package.rb
@@ -206,12 +206,10 @@ module Axlsx
     # @private
     def parts
       parts = [
-       {:entry => RELS_PN, :doc => relationships, :schema => RELS_XSD},
        {:entry => "xl/#{STYLES_PN}", :doc => workbook.styles, :schema => SML_XSD},
        {:entry => CORE_PN, :doc => @core, :schema => CORE_XSD},
        {:entry => APP_PN, :doc => @app, :schema => APP_XSD},
        {:entry => WORKBOOK_RELS_PN, :doc => workbook.relationships, :schema => RELS_XSD},
-       {:entry => CONTENT_TYPES_PN, :doc => content_types, :schema => CONTENT_TYPES_XSD},
        {:entry => WORKBOOK_PN, :doc => workbook, :schema => SML_XSD}
       ]
 
@@ -256,7 +254,11 @@ module Axlsx
       end
 
       # Sort parts for correct MIME detection
-      parts.sort_by { |part| part[:entry] }
+      [
+        {:entry => CONTENT_TYPES_PN, :doc => content_types, :schema => CONTENT_TYPES_XSD},
+        {:entry => RELS_PN, :doc => relationships, :schema => RELS_XSD},
+        *(parts.sort_by { |part| part[:entry] }.reverse)
+      ]
     end
 
     # Performs xsd validation for a signle document
diff --git a/test/tc_package.rb b/test/tc_package.rb
index b07f0d2f..6a943635 100644
--- a/test/tc_package.rb
+++ b/test/tc_package.rb
@@ -262,6 +262,10 @@ class TestPackage < Test::Unit::TestCase
     #no mystery parts
     assert_equal(25, p.size)
 
+    #sorted for correct MIME detection
+    assert_equal("[Content_Types].xml", p[0][:entry], "first entry should be `[Content_Types].xml`")
+    assert_equal("_rels/.rels", p[1][:entry], "second entry should be `_rels/.rels`")
+    assert_match(/\Axl\//, p[2][:entry], "third entry should begin with `xl/`")
   end
 
   def test_shared_strings_requires_part