Add test for cause on pty

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@65422 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

test/ruby/test_backtrace.rb

@@ -1,6 +1,7 @@
 # frozen_string_literal: false
 require 'test/unit'
 require 'tempfile'
+require 'pty'
 
 class TestBacktrace < Test::Unit::TestCase
   def test_exception
@@ -329,4 +330,52 @@ class TestBacktrace < Test::Unit::TestCase
     bar
     end;
   end
+
+  def assert_pty(args, test_stdin = "", dummy, expected)
+    actual = nil
+    PTY.spawn(EnvUtil.rubybin, *args) do |r, w, pid|
+      w.puts test_stdin
+      w.puts "__END__"
+      w.close
+      actual = r.read
+    end
+    expected = test_stdin.chomp + "\n__END__\n" + expected.to_s
+    expected.gsub!(/\n/, "\r\n")
+    assert_equal expected, actual
+  end
+
+  def test_tty_backtrace
+    err = "\e[1mTraceback\e[m (most recent call last):\n" +
+           "-:1:in `<main>': \e[1m\e[1;4munhandled exception\e[m\n"
+    assert_pty([], "raise", [], err)
+
+    err = "\e[1mTraceback\e[m (most recent call last):\n" +
+      "\t1: from -:4:in `<main>'\n" +
+      "-:2:in `foo': \e[1mfoo! (\e[1;4mRuntimeError\e[m\e[1m)\e[m\n"
+    assert_pty([], <<-"end;", [], err)
+    def foo
+      raise "foo!"
+    end
+    foo
+    end;
+
+    err = "\e[1mTraceback\e[m (most recent call last):\n" +
+      "\t2: from -:9:in `<main>'\n" +
+      "\t1: from -:5:in `bar'\n" +
+      "-:2:in `foo': \e[1mfoo! (\e[1;4mRuntimeError\e[m\e[1m)\e[m\n" +
+      "\t2: from -:9:in `<main>'\n" +
+      "\t1: from -:4:in `bar'\n" +
+      "-:7:in `rescue in bar': \e[1mbar! (\e[1;4mRuntimeError\e[m\e[1m)\e[m\n"
+    assert_pty([], <<-"end;", [], err)
+    def foo
+      raise "foo!"
+    end
+    def bar
+      foo
+    rescue
+      raise "bar!"
+    end
+    bar
+    end;
+  end
 end