Stop checking char from "read"

Because it's sometimes nil due to race condition.

1 files changed, 6 insertions, 3 deletions

diff --git a/test/readline/test_readline.rb b/test/readline/test_readline.rb
index 3661aace15..c0f1b30925 100644
--- a/test/readline/test_readline.rb
+++ b/test/readline/test_readline.rb
@@ -520,14 +520,16 @@ module BasetestReadline
     EnvUtil.invoke_ruby(["-I#{__dir__}", script.path], "", true, :merge_to_stdout) do |_in, _out, _, pid|
       Timeout.timeout(TIMEOUT) do
         log << "** START **"
-        while c = _out.read(1)
+        loop do
+          c = _out.read(1)
           log << c if c
           break if log.include?('input>')
         end
         log << "** SIGINT **"
         Process.kill(:INT, pid)
         sleep 0.1
-        while c = _out.read(1)
+        loop do
+          c = _out.read(1)
           log << c if c
           break if log.include?('TRAP')
         end
@@ -537,7 +539,8 @@ module BasetestReadline
         rescue Errno::EPIPE
           # The "write" will fail if Reline crashed by SIGINT.
         end
-        while c = _out.read(1)
+        loop do
+          c = _out.read(1)
           log << c if c
           if log.include?('FAILED')
             assert false, "Should handle SIGINT correctly but raised interrupt.\nLog: #{log}\n----"