test current directory in "teardown" method

even when current directory is changed within a test method
the "teardown" method should have same current directory
as "setup" and as the the original value in the test method.

t/CMDTEST_teardown.rb

@@ -0,0 +1,42 @@
+
+require "selftest_utils"
+
+class CMDTEST_teardown < Cmdtest::Testcase
+  include SelftestUtils
+
+  def test_teardown
+    create_file "CMDTEST_foo.rb", [
+      "class CMDTEST_foo < Cmdtest::Testcase",
+      "  def setup",
+      "    puts 'setup: ' + Dir.pwd",
+      "  end",
+      "",
+      "  def teardown",
+      "    puts 'teardown: ' + Dir.pwd",
+      "  end",
+      "",
+      "  def test_foo",
+      "    puts 'test: ' + Dir.pwd",
+      "    Dir.mkdir('subdir')",
+      "    Dir.chdir('subdir') do",
+      "      puts 'test_subdir: ' + Dir.pwd",
+      "    end",
+      "  end",
+      "end",
+    ]
+
+    cwd = Dir.pwd
+    cmdtest = "#{TOP}/bin/cmdtest.rb"
+    command = "ruby %s --quiet" % _quote(cmdtest)
+    cmd(command) do
+      stdout_equal [
+        "setup: #{cwd}/tmp-cmdtest-2/top/work",
+        "test: #{cwd}/tmp-cmdtest-2/top/work",
+        "test_subdir: #{cwd}/tmp-cmdtest-2/top/work/subdir",
+        "teardown: #{cwd}/tmp-cmdtest-2/top/work",
+      ]
+    end
+
+  end
+
+end