Attempt to alleviate strange Windows encoding error.

Error:
TestGeneratedSite#test_: generated sites should render latest post's content. :
Encoding::CompatibilityError: incompatible character encodings: IBM437 and UTF-8
    C:/projects/jekyll/test/test_generated_site.rb:22:in `include?'
    C:/projects/jekyll/test/test_generated_site.rb:22:in `block (2 levels) in <class:TestGeneratedSite>'
    C:/projects/jekyll/test/test_generated_site.rb:34:in `instance_exec'
    C:/projects/jekyll/test/test_generated_site.rb:34:in `block in create_test_from_should_hash'

test/source/_posts/2017-2-5-i-dont-like-zeroes.md

@@ -1,5 +1,5 @@
 ---
-foo: barj
+foo: bar
 ---
 I have an abbreviated date. Instead of "2017-02-05", I am instead "2017-2-5".
 Zeros have always seemed superfluous.

test/test_generated_site.rb

@@ -7,7 +7,10 @@ class TestGeneratedSite < JekyllUnitTest
 
       @site = fixture_site
       @site.process
-      @index = File.read(dest_dir("index.html"))
+      @index = File.read(
+        dest_dir("index.html"),
+        Utils.merged_file_read_opts(@site, {})
+      )
     end
 
     should "ensure post count is as expected" do