diff --git a/test/unit/debug.rb b/test/unit/debug.rb
index 88baf56..b694f21 100644
--- a/test/unit/debug.rb
+++ b/test/unit/debug.rb
@@ -24,7 +24,8 @@ class DebugEncoderTest < Test::Unit::TestCase
     ["   \n", :space],
     ["[]", :method],
     [:end_line, :head],
-  ].flatten
+  ]
+  TEST_INPUT.flatten!
   TEST_OUTPUT = <<-'DEBUG'.chomp
 integer(10)operator((\\\))string<content(test)>head[
 
diff --git a/test/unit/statistic.rb b/test/unit/statistic.rb
index 1326dca..776774d 100644
--- a/test/unit/statistic.rb
+++ b/test/unit/statistic.rb
@@ -24,7 +24,8 @@ class StatisticEncoderTest < Test::Unit::TestCase
     ["   \n", :space],
     ["[]", :method],
     [:end_line, :test],
-  ].flatten
+  ]
+  TEST_INPUT.flatten!
   TEST_OUTPUT = <<-'DEBUG'
 
 Code Statistics
@@ -56,4 +57,4 @@ Token Types (7):
     assert_equal TEST_OUTPUT, TEST_INPUT.statistic
   end
   
-end
\ No newline at end of file
+end
-- 
2.29.2