use ^@, ^A,... escapes in XML output + test

to avoid writing non-printable characters
to the XML file.

t/CMDTEST_junit.rb

@@ -0,0 +1,45 @@
+
+require "selftest_utils"
+
+class CMDTEST_junit < Cmdtest::Testcase
+
+  include SelftestUtils
+
+  def make_files(cmd="true")
+    create_file "CMDTEST_foo.rb", [
+      "class CMDTEST_foo1 < Cmdtest::Testcase",
+      "  def setup",
+      "    prepend_path #{BIN.inspect}",
+      "    prepend_path #{PLATFORM_BIN.inspect}",
+      "  end",
+      "",
+
+      '  def test_foo1',
+      '    cmd "%s" do' % cmd,
+      '    end',
+      '  end',
+      '',
+      'end',
+    ]
+  end
+
+  def test_1
+    make_files("echo_ctrl_chars.rb 1:5 27:32")
+    
+    cmd_cmdtest_verbose "--quiet --xml=tmp.xml" do
+      exit_nonzero
+      stdout_contain [
+        "### echo_ctrl_chars.rb 1:5 27:32",
+        "--- ERROR: wrong stdout",
+        /--- \^A --- \x01 ---/,
+        /--- \^B --- \x02 ---/,
+      ]
+      created_files "tmp.xml"
+      file_equal "tmp.xml", /--- \^A --- \^A ---/
+      file_equal "tmp.xml", /--- \^B --- \^B ---/
+      file_equal "tmp.xml", /--- \^\[ --- \^\[ ---/
+    end
+
+  end
+
+end