diff --git a/lib/e2mmap.rb b/lib/e2mmap.rb
index ac2fb2dd49..74e0f36577 100644
--- a/lib/e2mmap.rb
+++ b/lib/e2mmap.rb
@@ -146,7 +146,7 @@ module Exception2MessageMapper
       E2MM.Fail E2MM, ErrNotRegisteredException, err.inspect
     end
   end
-  class <<E2MM
+  class << E2MM
     alias Fail Raise
   end
 
@@ -160,7 +160,7 @@ module Exception2MessageMapper
     end
     nil
   end
-  class <<self
+  class << self
     alias message e2mm_message
   end
 
diff --git a/test/ruby/test_rubyoptions.rb b/test/ruby/test_rubyoptions.rb
index 4c49d31d93..3364d1c7be 100644
--- a/test/ruby/test_rubyoptions.rb
+++ b/test/ruby/test_rubyoptions.rb
@@ -182,7 +182,7 @@ class TestRubyOptions < Test::Unit::TestCase
   end
 
   def test_syntax_check
-    assert_in_out_err(%w(-c -e 1+1), "", ["Syntax OK"], [])
+    assert_in_out_err(%w(-c -e a=1+1), "", ["Syntax OK"], [])
   end
 
   def test_invalid_option
diff --git a/test/test_mathn.rb b/test/test_mathn.rb
index 7083568525..d36985378b 100644
--- a/test/test_mathn.rb
+++ b/test/test_mathn.rb
@@ -4,7 +4,7 @@ require_relative 'ruby/envutil'
 # mathn redefines too much. It must be isolated to child processes.
 class TestMathn < Test::Unit::TestCase
   def test_power
-    assert_in_out_err ['-r', 'mathn', '-e', '1**2'], "", [], [], '[ruby-core:25740]'
-    assert_in_out_err ['-r', 'mathn', '-e', '(1<<126)**2'], "", [], [], '[ruby-core:25740]'
+    assert_in_out_err ['-r', 'mathn', '-e', 'a=1**2'], "", [], [], '[ruby-core:25740]'
+    assert_in_out_err ['-r', 'mathn', '-e', 'a=(1<<126)**2'], "", [], [], '[ruby-core:25740]'
   end
 end