Add tests for config module

Add toml test dependency to toxfile
Add missing predump and postload hooks to top-level config serializer
Remove dummy paceholder test

tests/test_config.py

@@ -0,0 +1,57 @@
+import os
+from pathlib import Path
+
+import toml
+
+from keyosk import config
+from keyosk import constants
+from keyosk import datatypes
+
+
+TEST_CONFIG = {
+    "storage": {
+        "backend": "maria",
+        "sqlite": {
+            "path": "/foo/bar/baz.db",
+            "pragmas": {"foo": 1, "bar": "buzz", "baz": ["dog", "cat"]},
+        },
+        "maria": {
+            "schema": "authentifiy",
+            "host": "10.20.30.40",
+            "port": 6033,
+            "username": "qwerty",
+            "password": "uiop",
+        },
+    }
+}
+
+
+def test_default():
+    assert config.load() == config.KeyoskConfig()
+
+
+def test_roundtrip():
+    serializer = config.ConfigSerializer()
+    loaded = serializer.load(TEST_CONFIG)
+    assert TEST_CONFIG == serializer.dump(loaded)
+    assert loaded == serializer.load(serializer.dump(loaded))
+
+
+def test_settings():
+    loaded = config.ConfigSerializer().load(TEST_CONFIG)
+    assert loaded.storage.backend == datatypes.StorageBackend.MARIA
+    assert loaded.storage.sqlite.path == Path(TEST_CONFIG["storage"]["sqlite"]["path"])
+    assert loaded.storage.sqlite.pragmas == TEST_CONFIG["storage"]["sqlite"]["pragmas"]
+    for key, value in TEST_CONFIG["storage"]["maria"].items():
+        assert getattr(loaded.storage.maria, key) == value
+
+
+def test_filepath(tmp_path):
+    tmp_file = Path(tmp_path, "conf.toml")
+    os.environ[constants.ENV_CONFIG_PATH] = str(tmp_file)
+    with tmp_file.open("w+") as outfile:
+        toml.dump(TEST_CONFIG, outfile)
+
+    assert config.load(tmp_file) == config.ConfigSerializer().load(TEST_CONFIG)
+    tmp_file.unlink()
+    assert config.load(tmp_file) == config.KeyoskConfig()