Add --version flag to guidellm CLI (#240)

Implements a --version flag for the GuideLLM CLI that displays the
current version and exits cleanly.
The `--version` flag is one of the most fundamental and expected
features of any CLI tool. It's typically the first flag I try when
exploring a new command-line application .

## Usage

```bash
guidellm --version
# Output: guidellm version: 0.3.0.dev40
```

The version flag also appears in help output:
```bash
guidellm --help
```

## Testing

Wrote 7 unit tests which pass successfully:
```bash
pytest tests/unit/test_cli.py -v
```

---------

Signed-off-by: Harshith-umesh <[email protected]>
Signed-off-by: Elijah DeLee <[email protected]>
Signed-off-by: Samuel Monson <[email protected]>
Co-authored-by: Elijah DeLee <[email protected]>
Co-authored-by: Samuel Monson <[email protected]>

Author: 3 people

src/guidellm/__main__.py

@@ -25,6 +25,7 @@
 
 
 @click.group()
+@click.version_option(package_name="guidellm", message="guidellm version: %(version)s")
 def cli():
     pass
 
@@ -51,7 +52,7 @@ def benchmark():
             readable=True,
             file_okay=True,
             dir_okay=False,
-            path_type=Path,  # type: ignore[type-var]
+            path_type=Path,
         ),
         click.Choice(get_builtin_scenarios()),
     ),

tests/unit/test_cli.py

@@ -0,0 +1,105 @@
+"""
+Unit tests for CLI functionality, specifically the version flag.
+"""
+
+import pytest
+from click.testing import CliRunner
+
+from guidellm.__main__ import cli
+
+
+@pytest.mark.smoke
+def test_version_flag_long():
+    """Test that --version flag works correctly."""
+    runner = CliRunner()
+    result = runner.invoke(cli, ["--version"])
+
+    assert result.exit_code == 0
+    assert "guidellm version:" in result.output
+    assert result.output.strip().startswith("guidellm version:")
+
+
+@pytest.mark.smoke
+def test_version_flag_displays_actual_version():
+    """Test that --version displays the actual version from version.py."""
+    runner = CliRunner()
+    result = runner.invoke(cli, ["--version"])
+
+    assert result.exit_code == 0
+    import re
+
+    version_pattern = r"guidellm version: \d+\.\d+"
+    assert re.search(version_pattern, result.output)
+
+
+@pytest.mark.smoke
+def test_version_flag_exits_cleanly():
+    """Test that --version exits without processing other commands."""
+    runner = CliRunner()
+    result = runner.invoke(cli, ["--version", "benchmark"])
+
+    assert result.exit_code == 0
+    assert "guidellm version:" in result.output
+    assert "Commands to run a new benchmark" not in result.output
+
+
+@pytest.mark.smoke
+def test_help_shows_version_option():
+    """Test that --help shows the --version option."""
+    runner = CliRunner()
+    result = runner.invoke(cli, ["--help"])
+
+    assert result.exit_code == 0
+    assert "--version" in result.output
+    assert "Show the version and exit" in result.output
+
+
+@pytest.mark.smoke
+def test_other_commands_still_work():
+    """Test that other CLI commands still work after adding version flag."""
+    runner = CliRunner()
+    result = runner.invoke(cli, ["--help"])
+
+    assert result.exit_code == 0
+    assert "benchmark" in result.output
+    assert "config" in result.output
+    assert "preprocess" in result.output
+
+
+@pytest.mark.smoke
+def test_version_flag_case_sensitivity():
+    """Test that --version flag is case sensitive."""
+    runner = CliRunner()
+
+    result = runner.invoke(cli, ["--version"])
+    assert result.exit_code == 0
+    assert "guidellm version:" in result.output
+
+    # --VERSION should not work
+    result = runner.invoke(cli, ["--VERSION"])
+    assert result.exit_code != 0
+    assert "No such option" in result.output
+
+
+@pytest.mark.integration
+def test_version_integration_with_actual_version():
+    """Integration test to verify version matches importlib.metadata."""
+    import importlib.metadata
+
+    try:
+        actual_version = importlib.metadata.version("guidellm")
+
+        runner = CliRunner()
+        result = runner.invoke(cli, ["--version"])
+
+        assert result.exit_code == 0
+        expected_output = f"guidellm version: {actual_version}"
+        assert expected_output in result.output
+    except importlib.metadata.PackageNotFoundError:
+        # If package is not installed, the CLI should show an error
+        # This is expected behavior when the package isn't properly installed
+        runner = CliRunner()
+        result = runner.invoke(cli, ["--version"])
+
+        # Click will handle the error when package is not found
+        assert result.exit_code != 0