1 files changed, 129 insertions, 0 deletions
diff --git a/pw_build/py/project_builder_prefs_test.py b/pw_build/py/project_builder_prefs_test.py
new file mode 100644
index 000000000..f128bee2b
--- /dev/null
+++ b/pw_build/py/project_builder_prefs_test.py
@@ -0,0 +1,129 @@
+# Copyright 2022 The Pigweed Authors
+#
+# Licensed under the Apache License, Version 2.0 (the "License"); you may not
+# use this file except in compliance with the License. You may obtain a copy of
+# the License at
+#
+#     https://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+# License for the specific language governing permissions and limitations under
+# the License.
+"""Tests for pw_build.project_builder_prefs"""
+
+import argparse
+import copy
+from pathlib import Path
+import tempfile
+from typing import Any, Dict
+import unittest
+from unittest.mock import MagicMock
+
+from pw_build.project_builder_argparse import add_project_builder_arguments
+from pw_build.project_builder_prefs import (
+    ProjectBuilderPrefs,
+    _DEFAULT_CONFIG,
+    load_defaults_from_argparse,
+)
+
+
+def _create_tempfile(content: str) -> Path:
+    with tempfile.NamedTemporaryFile(
+        prefix=f'{__package__}', delete=False
+    ) as output_file:
+        output_file.write(content.encode('UTF-8'))
+        return Path(output_file.name)
+
+
+class TestProjectBuilderPrefs(unittest.TestCase):
+    """Tests for ProjectBuilderPrefs."""
+
+    def setUp(self):
+        self.maxDiff = None  # pylint: disable=invalid-name
+
+    def test_load_no_existing_files(self) -> None:
+        # Create a prefs instance with no loaded config.
+        prefs = ProjectBuilderPrefs(
+            load_argparse_arguments=add_project_builder_arguments,
+            project_file=False,
+            project_user_file=False,
+            user_file=False,
+        )
+        # Construct an expected result config.
+        expected_config: Dict[Any, Any] = {}
+        expected_config.update(_DEFAULT_CONFIG)
+        expected_config.update(
+            load_defaults_from_argparse(add_project_builder_arguments)
+        )
+
+        self.assertEqual(
+            prefs._config, expected_config  # pylint: disable=protected-access
+        )
+
+    def test_apply_command_line_args(self) -> None:
+        """Check command line args are applied to watch preferences."""
+        # Load default command line arg values.
+        defaults_from_argparse = load_defaults_from_argparse(
+            add_project_builder_arguments
+        )
+
+        # Create a prefs instance with the test config file.
+        prefs = ProjectBuilderPrefs(
+            load_argparse_arguments=add_project_builder_arguments,
+            project_file=False,
+            project_user_file=False,
+            user_file=False,
+        )
+
+        # Construct an expected result config.
+        expected_config: Dict[Any, Any] = copy.copy(_DEFAULT_CONFIG)
+        expected_config.update(defaults_from_argparse)
+
+        # pylint: disable=protected-access
+        prefs._update_config = MagicMock(  # type: ignore
+            wraps=prefs._update_config
+        )
+        # pylint: enable=protected-access
+
+        args_dict = copy.deepcopy(defaults_from_argparse)
+        changed_args = {
+            'jobs': 8,
+            'colors': False,
+            'build_system_commands': [
+                ['out', 'bazel build'],
+                ['out', 'bazel test'],
+            ],
+        }
+        args_dict.update(changed_args)
+
+        prefs.apply_command_line_args(argparse.Namespace(**args_dict))
+
+        # apply_command_line_args modifies build_system_commands to match the
+        # prefs dict format.
+        changed_args['build_system_commands'] = {
+            'default': {'commands': [{'command': 'ninja', 'extra_args': []}]},
+            'out': {
+                'commands': [
+                    {'command': 'bazel', 'extra_args': ['build']},
+                    {'command': 'bazel', 'extra_args': ['test']},
+                ],
+            },
+        }
+
+        # Check that only args changed from their defaults are applied.
+        # pylint: disable=protected-access
+        prefs._update_config.assert_called_once_with(changed_args)
+        # pylint: enable=protected-access
+
+        # Check the result includes the project_config settings and the
+        # changed_args.
+        expected_config.update(changed_args)
+        # pylint: disable=protected-access
+        self.assertEqual(prefs._config, expected_config)
+        # pylint: enable=protected-access
+
+
+if __name__ == '__main__':
+    unittest.main()