Json configuration (#141)

* Add json config
* Adjust code to new config

---------

Co-authored-by: Chris <git@nootch.de>

tests/test_server.py

@@ -1,10 +1,24 @@
+from http import HTTPStatus
+from pathlib import Path
+
 import requests
 
-from akkudoktoreos.config import prediction_hours
+from akkudoktoreos.config import CONFIG_FILE_NAME, load_config
 
 
-def test_server(server):
+def test_fixture_setup(server, tmp_path: Path) -> None:
+    """Test if the fixture sets up the server with the env var."""
+    # validate correct path in server
+    config = load_config(tmp_path, False)
+    assert tmp_path.joinpath(CONFIG_FILE_NAME).is_file()
+    cache = tmp_path / config.directories.cache
+    assert cache.is_dir()
+
+
+def test_server(server, tmp_path: Path):
     """Test the server."""
     result = requests.get(f"{server}/gesamtlast_simple?year_energy=2000&")
-    assert result.status_code == 200
-    assert len(result.json()) == prediction_hours
+    assert result.status_code == HTTPStatus.OK
+
+    config = load_config(tmp_path, False)
+    assert len(result.json()) == config.eos.prediction_hours