diff --git a/tests/test_cli.py b/tests/test_cli.py
new file mode 100644
index 0000000..ca39e1e
--- /dev/null
+++ b/tests/test_cli.py
@@ -0,0 +1,97 @@
+import argparse
+import os
+from unittest.mock import patch, mock_open
+
+import pytest
+
+from pydumpling.cli import main, parser
+from pydumpling.helpers import validate_file_name
+
+
+@patch('os.path.exists')
+def test_validate_file_name_valid(mock_exists):
+    mock_exists.return_value = True
+    result = validate_file_name("test.dump")
+    assert result == "test.dump"
+    mock_exists.assert_called_once_with("test.dump")
+
+
+def test_validate_file_name_invalid():
+    with pytest.raises(argparse.ArgumentTypeError) as exc:
+        validate_file_name("test.txt")
+    assert str(exc.value) == "File must be .dump file"
+
+
+def test_validate_file_name_empty():
+    with pytest.raises(argparse.ArgumentTypeError) as exc:
+        validate_file_name("")
+    assert str(exc.value) == "File must be .dump file"
+
+
+@patch('os.path.exists')
+@patch('pydumpling.cli.load_dumpling')
+@patch('pydumpling.cli.print_traceback_and_except')
+def test_main_print(mock_print, mock_load, mock_exists):
+    mock_exists.return_value = True
+    test_args = ['--print', 'test.dump']
+    with patch('sys.argv', ['pydumpling'] + test_args):
+        main()
+        mock_load.assert_called_once_with('test.dump')
+        mock_print.assert_called_once_with(mock_load.return_value)
+
+
+@patch('os.path.exists')
+@patch('pydumpling.cli.debug_dumpling')
+def test_main_debug(mock_debug, mock_exists):
+    mock_exists.return_value = True
+    test_args = ['--debug', 'test.dump']
+    with patch('sys.argv', ['pydumpling'] + test_args):
+        main()
+        mock_debug.assert_called_once_with('test.dump')
+
+
+@patch('os.path.exists')
+@patch('pydumpling.cli.r_post_mortem')
+def test_main_rdebug(mock_rpost, mock_exists):
+    mock_exists.return_value = True
+    test_args = ['--rdebug', 'test.dump']
+    with patch('sys.argv', ['pydumpling'] + test_args):
+        main()
+        mock_rpost.assert_called_once_with('test.dump')
+
+
+def test_parser_no_args():
+    with pytest.raises(SystemExit):
+        parser.parse_args([])
+
+
+def test_parser_multiple_actions():
+    with pytest.raises(SystemExit):
+        parser.parse_args(['--print', '--debug', 'test.dump'])
+
+
+def test_parser_missing_filename():
+    with pytest.raises(SystemExit):
+        parser.parse_args(['--print'])
+
+
+@patch('os.path.exists')
+def test_parser_invalid_filename(mock_exists):
+    mock_exists.return_value = False
+    with pytest.raises(SystemExit):
+        parser.parse_args(['--print', 'test.txt'])
+
+
+def test_parser_help(capsys):
+    with pytest.raises(SystemExit):
+        parser.parse_args(['--help'])
+    captured = capsys.readouterr()
+    assert 'pydumpling cli tools' in captured.out
+
+
+@patch('os.path.exists')
+def test_validate_file_name_not_found(mock_exists):
+    mock_exists.return_value = False
+    with pytest.raises(argparse.ArgumentTypeError) as exc:
+        validate_file_name("test.dump")
+    assert str(exc.value) == "File test.dump not found"