diff --git a/test/unit/lib/redmine/scm/adapters/git_adapter_test.rb b/test/unit/lib/redmine/scm/adapters/git_adapter_test.rb
index 15200184e..1189e6cff 100644
--- a/test/unit/lib/redmine/scm/adapters/git_adapter_test.rb
+++ b/test/unit/lib/redmine/scm/adapters/git_adapter_test.rb
@@ -400,7 +400,7 @@ begin
         str_felix_hex  = FELIX_HEX.dup
         last_rev_author = last_rev.author
         if last_rev_author.respond_to?(:force_encoding)
-          last_rev_author.force_encoding('UTF-8')
+          str_felix_hex.force_encoding('ASCII-8BIT')
         end
         assert_equal "ed5bb786bbda2dee66a2d50faf51429dbc043a7b", last_rev.scmid
         assert_equal "ed5bb786bbda2dee66a2d50faf51429dbc043a7b", last_rev.identifier