Add some testing of CLI loading of config

The unit testing was lacking any testing at all. This change adds
coverage of CLI loading of configuration files.

Signed-off-by: Eric Brown <[email protected]>

precli/cli/main.py

@@ -163,20 +163,32 @@ def setup_arg_parser():
         parser.print_usage()
         sys.exit(2)
 
-    return args
+    return parser, args
 
 
-def load_config(config: dict, targets: list[str]) -> dict:
+def load_config(
+    parser: argparse.ArgumentParser, config: dict, targets: list[str]
+) -> dict:
     if config:
-        return tomllib.load(config)
+        try:
+            return tomllib.load(config)
+        except tomllib.TOMLDecodeError as err:
+            parser.error(
+                f"argument -c/--config: can't load '{config.name}': {err}"
+            )
     else:
         default_confs = (".precli.toml", "precli.toml", "pyproject.toml")
         for target in filter(os.path.isdir, targets):
             for conf in default_confs:
                 path = pathlib.Path(target) / conf
-                if path.exists():
-                    with open(path, "rb") as f:
-                        return tomllib.load(f)
+                try:
+                    if path.exists():
+                        with open(path, "rb") as f:
+                            return tomllib.load(f)
+                except tomllib.TOMLDecodeError as err:
+                    # TODO: Log but don't exit
+                    pass
+
     return {}
 
 
@@ -364,10 +376,10 @@ def main():
     logging.getLogger("urllib3").setLevel(debug)
 
     # Setup the command line arguments
-    args = setup_arg_parser()
+    parser, args = setup_arg_parser()
 
     # Load optional configuration file
-    config = load_config(args.config, args.targets)
+    config = load_config(parser, args.config, args.targets)
 
     # CLI enabled/disabled override any config in files
     config["enabled"] = (

tests/unit/cli/test_main.py

@@ -0,0 +1,47 @@
+# Copyright 2024 Secure Sauce LLC
+# SPDX-License-Identifier: BUSL-1.1
+import json
+import os
+import tempfile
+from unittest import mock
+
+import pytest
+
+from precli.cli import main
+
+
+class TestMain:
+    @classmethod
+    def setup_class(cls):
+        cls.base_path = os.path.join(
+            "tests",
+            "unit",
+            "cli",
+            "examples",
+        )
+        cls.current_dir = os.getcwd()
+
+    @classmethod
+    def teardown_class(cls):
+        os.chdir(cls.current_dir)
+
+
+    @mock.patch("sys.argv", ["precli", "-c", "missing_file.toml"])
+    def test_main_config_not_found(self):
+        with pytest.raises(SystemExit) as excinfo:
+            main.main()
+        assert str(excinfo.value) == "2"
+
+    @mock.patch("sys.argv", ["precli", "-c", "not_toml.json", "."])
+    def test_main_invalid_config(self):
+        temp_dir = tempfile.mkdtemp()
+        os.chdir(temp_dir)
+        config = {
+            "enable": ["PY001"]
+        }
+        with open("not_toml.json", "w") as fd:
+            json.dump(config, fd)
+
+        with pytest.raises(SystemExit) as excinfo:
+            main.main()
+        assert str(excinfo.value) == "2"