xargs: fix xargs -e; added test for that

testsuite/xargs.tests

@@ -0,0 +1,19 @@
+#!/bin/sh
+# Copyright 2008 by Denys Vlasenko
+# Licensed under GPL v2, see file LICENSE for details.
+
+. testing.sh
+
+# testing "test name" "command" "expected result" "file input" "stdin"
+
+testing "xargs stops on underscore" \
+	"xargs" \
+	"a\n" \
+	"" "a\n_\nb\n"
+
+testing "xargs -e without param" \
+	"xargs -e" \
+	"a _ b\n" \
+	"" "a\n_\nb\n"
+
+exit $FAILCOUNT