config: Start module.

Ultimately all values that come from user configuration will be generated
here.

conservancy_beancount/config.py

@@ -0,0 +1,29 @@
+"""User configuration for Conservancy bookkeeping tools"""
+# Copyright © 2020  Brett Smith
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Affero General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU Affero General Public License for more details.
+#
+# You should have received a copy of the GNU Affero General Public License
+# along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+import os
+
+from pathlib import Path
+from typing import (
+    Optional,
+)
+
+class Config:
+    def repository_path(self) -> Optional[Path]:
+        try:
+            return Path(os.environ['CONSERVANCY_REPOSITORY'])
+        except (KeyError, ValueError):
+            return None

tests/test_config.py

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+"""Test Config class"""
+# Copyright © 2020  Brett Smith
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Affero General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU Affero General Public License for more details.
+#
+# You should have received a copy of the GNU Affero General Public License
+# along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+import contextlib
+import os
+
+from conservancy_beancount import config as config_mod
+
+def _update_environ(updates):
+    for key, value in updates.items():
+        if value is None:
+            os.environ.pop(key, None)
+        else:
+            os.environ[key] = str(value)
+
+@contextlib.contextmanager
+def update_environ(**kwargs):
+    revert = {key: os.environ.get(key) for key in kwargs}
+    _update_environ(kwargs)
+    yield
+    _update_environ(revert)
+
+def test_repository_from_environment():
+    with update_environ(CONSERVANCY_REPOSITORY='/usr/local'):
+        config = config_mod.Config()
+        assert config.repository_path().parts == ('/', 'usr', 'local')
+
+def test_no_repository():
+    with update_environ(CONSERVANCY_REPOSITORY=None):
+        config = config_mod.Config()
+        assert config.repository_path() is None