Basic evaluate CLI command / codepath (#2188)

* basic evaluate CLI command / codepath

* tests for evaluate CLI command

* fixes and cleanup

* review comments; slightly DRYing up things

---------

Co-authored-by: Dan Saunders <dan@axolotl.ai>

tests/cli/test_cli_base.py

@@ -0,0 +1,73 @@
+"""Base test class for CLI commands."""
+
+from pathlib import Path
+from unittest.mock import patch
+
+from axolotl.cli.main import cli
+
+
+class BaseCliTest:
+    """Base class for CLI command tests."""
+
+    def _test_cli_validation(self, cli_runner, command: str):
+        """Test CLI validation for a command.
+
+        Args:
+            cli_runner: CLI runner fixture
+            command: Command to test (train/evaluate)
+        """
+        # Test missing config file
+        result = cli_runner.invoke(cli, [command, "--no-accelerate"])
+        assert result.exit_code != 0
+
+        # Test non-existent config file
+        result = cli_runner.invoke(cli, [command, "nonexistent.yml", "--no-accelerate"])
+        assert result.exit_code != 0
+        assert "Error: Invalid value for 'CONFIG'" in result.output
+
+    def _test_basic_execution(
+        self, cli_runner, tmp_path: Path, valid_test_config: str, command: str
+    ):
+        """Test basic execution with accelerate.
+
+        Args:
+            cli_runner: CLI runner fixture
+            tmp_path: Temporary path fixture
+            valid_test_config: Valid config fixture
+            command: Command to test (train/evaluate)
+        """
+        config_path = tmp_path / "config.yml"
+        config_path.write_text(valid_test_config)
+
+        with patch("subprocess.run") as mock:
+            result = cli_runner.invoke(cli, [command, str(config_path)])
+
+            assert mock.called
+            assert mock.call_args.args[0] == [
+                "accelerate",
+                "launch",
+                "-m",
+                f"axolotl.cli.{command}",
+                str(config_path),
+                "--debug-num-examples",
+                "0",
+            ]
+            assert mock.call_args.kwargs == {"check": True}
+            assert result.exit_code == 0
+
+    def _test_cli_overrides(self, tmp_path: Path, valid_test_config: str):
+        """Test CLI argument overrides.
+
+        Args:
+            tmp_path: Temporary path fixture
+            valid_test_config: Valid config fixture
+            command: Command to test (train/evaluate)
+        """
+        config_path = tmp_path / "config.yml"
+        output_dir = tmp_path / "model-out"
+
+        test_config = valid_test_config.replace(
+            "output_dir: model-out", f"output_dir: {output_dir}"
+        )
+        config_path.write_text(test_config)
+        return config_path