diff --git a/t/CMDTEST_chdir.rb b/t/CMDTEST_chdir.rb
new file mode 100644
index 0000000..7c40787
--- /dev/null
+++ b/t/CMDTEST_chdir.rb
@@ -0,0 +1,105 @@
+
+require "selftest_utils"
+
+class CMDTEST_chdir < Cmdtest::Testcase
+
+  include SelftestUtils
+
+  # The Ruby builtin "Dir.chdir" and "chdir" from "cmdtest"
+  # can be used in a test-method. In both cases the following
+  # should happen:
+  #
+  # - the "current directory" of the "cmdtest" Ruby process should be set,
+  #   so later code in the samne test-method can rely on the new
+  #   current directory.
+  #
+  # - when a command is executed with "cmd", it should get the same
+  #   current directory as the "cmdtest" Ruby process.
+  #
+
+  # without any "chdir"
+  def test_chdir_NONE
+    create_CMDTEST_foo [
+      "create_file 'SUBDIR/.flagfile', ''",
+      "system 'pwd'",
+    ]
+    cmd_cmdtest do
+      stdout_equal /^\/.*\/top\/work$/
+
+    end
+  end
+
+  # "chdir" to a subdirectory
+  def test_chdir_SUBDIR
+    create_CMDTEST_foo [
+      "create_file 'SUBDIR/.flagfile', ''",
+      "chdir 'SUBDIR'",
+      "system 'pwd'",
+    ]
+    cmd_cmdtest do
+      stdout_equal /^\/.*\/top\/work\/SUBDIR$/
+
+    end
+  end
+
+  # "Dir.chdir" to a subdirectory
+  def test_dir_chdir_SUBDIR
+    create_CMDTEST_foo [
+      "create_file 'SUBDIR/.flagfile', ''",
+      "Dir.chdir 'SUBDIR'",
+      "system 'pwd'",
+    ]
+    cmd_cmdtest do
+      stdout_equal /^\/.*\/top\/work\/SUBDIR$/
+
+    end
+  end
+
+  # "cmd" after no "chdir"
+  def test_chdir_NONE_cmd
+    create_CMDTEST_foo [
+      "create_file 'SUBDIR/.flagfile', ''",
+      "cmd 'echo PWD=$(pwd)' do",
+      "    stdout_equal /^PWD=\\/.*\\/top\\/work$/",
+      "end",
+    ]
+    cmd_cmdtest do
+      stdout_equal [
+        "### echo PWD=$(pwd)",
+      ]
+    end
+  end
+
+  # "cmd" after "chdir"
+  def test_chdir_SUBDIR_cmd
+    create_CMDTEST_foo [
+      "create_file 'SUBDIR/.flagfile', ''",
+      "chdir 'SUBDIR'",
+      "cmd 'echo PWD=$(pwd)' do",
+      "    stdout_equal /^PWD=\\/.*\\/top\\/work\\/SUBDIR$/",
+      "end",
+    ]
+    cmd_cmdtest do
+      stdout_equal [
+        "### echo PWD=$(pwd)",
+      ]
+    end
+  end
+
+  # "cmd" after "Dir.chdir"
+  def test_dir_chdir_SUBDIR_cmd
+    create_CMDTEST_foo [
+      "create_file 'SUBDIR/.flagfile', ''",
+      "Dir.chdir 'SUBDIR'",
+      "cmd 'echo PWD=$(pwd)' do",
+      "    stdout_equal /^PWD=\\/.*\\/top\\/work\\/SUBDIR$/",
+      "end",
+    ]
+    cmd_cmdtest do
+      stdout_equal [
+        "### echo PWD=$(pwd)",
+      ]
+    end
+  end
+
+end