diff --git a/test/assertion_helper_test.rb b/test/assertion_helper_test.rb
index 88138f2bc..b75b2b716 100644
--- a/test/assertion_helper_test.rb
+++ b/test/assertion_helper_test.rb
@@ -6,7 +6,7 @@ module DEBUGGER__
   class AssertLineTextTest < TestCase
     def program
       <<~RUBY
-        a = 1
+        1| a = 1
       RUBY
     end
 
diff --git a/test/support/test_case.rb b/test/support/test_case.rb
index e2163d471..c9ca263e2 100644
--- a/test/support/test_case.rb
+++ b/test/support/test_case.rb
@@ -16,7 +16,7 @@ def teardown
     end
 
     def remove_temp_file
-      File.unlink(@temp_file)
+      File.unlink(@temp_file) if @temp_file
       @temp_file = nil
     end
 
diff --git a/test/support/utils.rb b/test/support/utils.rb
index 5a211c29f..b1382121d 100644
--- a/test/support/utils.rb
+++ b/test/support/utils.rb
@@ -16,6 +16,8 @@ def create_message fail_msg
 
     # This method will execute both local and remote mode by default.
     def debug_code(program, boot_options: '-r debug/run', remote: true, &block)
+      check_line_num!(program)
+
       @scenario = block
       write_temp_file(strip_line_num(program))
       inject_lib_to_load_path
@@ -29,15 +31,12 @@ def debug_code(program, boot_options: '-r debug/run', remote: true, &block)
         debug_on_unix_domain_socket
         debug_on_tcpip
       end
-
-      check_line_num!(program)
     end
 
-    DEBUG_MODE = false
     ASK_CMD = %w[quit delete kill undisplay]
 
     def debug_print msg
-      print msg if DEBUG_MODE
+      print msg if ENV['RUBY_DEBUG_TEST_DEBUG_MODE']
     end
 
     RUBY = RbConfig.ruby
diff --git a/test/test_utils_test.rb b/test/test_utils_test.rb
index 9241e79a7..cfce86d44 100644
--- a/test/test_utils_test.rb
+++ b/test/test_utils_test.rb
@@ -6,7 +6,7 @@ module DEBUGGER__
   class PseudoTerminalTest < TestCase
     def program
       <<~RUBY
-        a = 1
+        1| a = 1
       RUBY
     end