fix version cli flag

src/cookiecutter_python/cli.py

@@ -2,6 +2,7 @@
 
 import os
 import sys
+import typing as t
 
 import click
 
@@ -17,10 +18,10 @@
 
 def version_msg():
     """Message about Python Generator version, location and Python version."""
-    python_version = sys.version[:3]
+    python_version: t.Tuple[int, int, int] = sys.version_info[:3]
     message = u'Python Generator %(version)s from {} (Python {})'
     location = os.path.dirname(this_file_location)
-    return message.format(location, python_version)
+    return message.format(location, ".".join(map(str, python_version)))
 
 
 @click.command(context_settings=dict(help_option_names=[u'-h', u'--help']))

tests/test_build_backend_sdist.py

@@ -146,6 +146,7 @@ def sdist_expected_correct_file_structure():
         # 'src/stubs/requests_futures/sessions.pyi',
     )
     TESTS = (
+        'tests/test_version_string.py',
         'tests/test_git_sdk.py',
         'tests/test_git_porcelain.py',
         'tests/test_is_repo_clean_function.py',

tests/test_version_string.py

@@ -0,0 +1,50 @@
+from pathlib import Path
+
+import pytest
+
+
+def test_version_msg_function_returns_expected_string(distro_loc: Path):
+    # GIVEN the version_msg function
+    from cookiecutter_python.cli import version_msg
+
+    # WHEN the version_msg function is called
+    result: str = version_msg()
+
+    # THEN it should return the expected string
+    import sys
+
+    EXPECTED_PYTHON_VERSION: str = ".".join(map(str, sys.version_info[:3]))
+
+    EXPECTED_PARENT_DIR_OF_COOKIECUTTER_PYTHON: Path = distro_loc.parent
+
+    assert result == (
+        f'Python Generator %(version)s from {EXPECTED_PARENT_DIR_OF_COOKIECUTTER_PYTHON} (Python {EXPECTED_PYTHON_VERSION})'
+    )
+
+
+@pytest.mark.runner_setup(mix_stderr=False)
+def test_cli_version_flag_returns_expected_string(
+    distro_loc: Path,
+    isolated_cli_runner,
+):
+    from cookiecutter_python import __version__
+    from cookiecutter_python.cli import main
+
+    result = isolated_cli_runner.invoke(
+        main,
+        args=['--version'],
+        input=None,
+        env=None,
+        catch_exceptions=False,
+    )
+    assert result.exit_code == 0
+
+    import sys
+
+    EXPECTED_PYTHON_VERSION: str = ".".join(map(str, sys.version_info[:3]))
+
+    EXPECTED_PARENT_DIR_OF_COOKIECUTTER_PYTHON: Path = distro_loc.parent
+
+    assert result.stdout == (
+        f'Python Generator {__version__} from {EXPECTED_PARENT_DIR_OF_COOKIECUTTER_PYTHON} (Python {EXPECTED_PYTHON_VERSION})\n'
+    )