Cover the example configs with a parsing test

Nothing in the test suite or CI reads examples/, which is how the sample
config could stay broken for years while every other config surface kept
working. Parse both example files through ArchConfigHandler, and check
the partition entries directly since the parser only reaches them when
the configured device exists on the machine, which is never true in CI.

tests/conftest.py

@@ -8,6 +8,16 @@ def config_fixture() -> Path:
 	return Path(__file__).parent / 'data' / 'test_config.json'
 
 
+@pytest.fixture(scope='session')
+def example_config_fixture() -> Path:
+	return Path(__file__).parent.parent / 'examples' / 'config-sample.json'
+
+
+@pytest.fixture(scope='session')
+def example_creds_fixture() -> Path:
+	return Path(__file__).parent.parent / 'examples' / 'creds-sample.json'
+
+
 @pytest.fixture(scope='session')
 def btrfs_config_fixture() -> Path:
 	return Path(__file__).parent / 'data' / 'test_config_btrfs.json'

tests/test_args.py

@@ -1,3 +1,4 @@
+import json
 import os
 from importlib.metadata import version
 from pathlib import Path
@@ -17,7 +18,7 @@ from archinstall.lib.models.application import (
 )
 from archinstall.lib.models.authentication import AuthenticationConfiguration, U2FLoginConfiguration, U2FLoginMethod
 from archinstall.lib.models.bootloader import Bootloader, BootloaderConfiguration
-from archinstall.lib.models.device import DiskLayoutConfiguration, DiskLayoutType
+from archinstall.lib.models.device import DiskLayoutConfiguration, DiskLayoutType, Size
 from archinstall.lib.models.locale import LocaleConfiguration
 from archinstall.lib.models.mirrors import CustomRepository, CustomServer, MirrorConfiguration, MirrorRegion, SignCheck, SignOption
 from archinstall.lib.models.network import NetworkConfiguration, Nic, NicType
@@ -388,3 +389,50 @@ def test_encrypted_creds_with_env_var(
 			groups=[],
 		),
 	]
+
+
+def test_example_config_parsing(
+	monkeypatch: MonkeyPatch,
+	example_config_fixture: Path,
+	example_creds_fixture: Path,
+) -> None:
+	monkeypatch.setattr(
+		'sys.argv',
+		[
+			'archinstall',
+			'--config',
+			str(example_config_fixture),
+			'--creds',
+			str(example_creds_fixture),
+		],
+	)
+
+	handler = ArchConfigHandler()
+	arch_config = handler.config
+
+	assert arch_config.disk_config is not None
+	assert arch_config.profile_config is not None
+	assert arch_config.auth_config is not None
+	assert arch_config.auth_config.users
+
+
+def test_example_config_partitions(example_config_fixture: Path) -> None:
+	# partition entries are only parsed when the configured device is present on
+	# the machine, which is never the case in CI, so read them here directly
+	config = json.loads(example_config_fixture.read_text())
+
+	for device in config['disk_config']['device_modifications']:
+		previous_end = None
+
+		for partition in device['partitions']:
+			assert 'dev_path' in partition
+
+			start = Size.parse_args(partition['start'])
+			end = start + Size.parse_args(partition['size'])
+
+			assert start.is_valid_start()
+
+			if previous_end is not None:
+				assert start >= previous_end
+
+			previous_end = end