Add test case for socket:unget roundtrip

Author: daurnimator

regress/90-unget-textmode.lua

@@ -0,0 +1,28 @@
+#!/bin/sh
+_=[[
+	. "${0%%/*}/regress.sh"
+	exec runlua "$0" "$@"
+]]
+require"regress".export".*"
+
+local function test_with_mode(str, mode)
+	local c, s = socket.pair()
+	check(s:xwrite(str, "bn"))
+	local foo = c:xread(-99999, mode)
+	check(c:unget(foo, mode))
+	local bar = c:xread(-99999, mode)
+	check(foo == bar, "unget + read does not round trip")
+end
+local function test(str)
+	info("testing: %q", str)
+	test_with_mode(str, "t")
+	test_with_mode(str, "b")
+end
+
+test'test'
+test'test\n'
+test'hi\r\nthere\nworld\r'
+test'\n\n'
+test'foo\r\r\n'
+
+say("OK")