enhance: Add comprehensive .gitignore for deb-mock project

- Add mock-specific build artifacts (chroot/, mock-*, mockroot/)
- Include package build files (*.deb, *.changes, *.buildinfo)
- Add development tools (.coverage, .pytest_cache, .tox)
- Include system files (.DS_Store, Thumbs.db, ._*)
- Add temporary and backup files (*.tmp, *.bak, *.backup)
- Include local configuration overrides (config.local.yaml, .env.local)
- Add test artifacts and documentation builds
- Comprehensive coverage for Python build system project

This ensures build artifacts, chroot environments, and development
tools are properly ignored in version control.

mock/tests/test_config_loader.py

@@ -0,0 +1,52 @@
+"""
+Tests for mockbuild.config
+"""
+
+# pylint: disable=missing-class-docstring
+# pylint: disable=missing-function-docstring
+# pylint: disable=attribute-defined-outside-init
+
+import pwd
+import os
+import shutil
+import tempfile
+
+from unittest import mock
+from mockbuild.config import simple_load_config
+
+
+class TestConfigLoader:
+    def setup_method(self):
+        testdir = os.path.dirname(os.path.realpath(__file__))
+        self.configdir = os.path.join(testdir, "data", "config-001")
+        self.homedir = tempfile.mkdtemp(prefix='mock-test-home')
+        homedata = os.path.join(testdir, "data", "home-001")
+        self.username = pwd.getpwuid(os.getuid())[0]
+        userdir = os.path.join(self.homedir, self.username)
+        shutil.copytree(homedata, userdir)
+
+    def test_config_paths(self):
+        with mock.patch("mockbuild.config.os.path.expanduser") as patch:
+            patch.side_effect = lambda x: x.replace("~", self.homedir + "/")
+            config = simple_load_config('fedora-rawhide-x86_64', self.configdir)
+        assert set(config["config_paths"]) == {
+            os.path.join(self.configdir, "site-defaults.cfg"),
+            os.path.join(self.configdir, "fedora-rawhide-x86_64.cfg"),
+            os.path.join(self.configdir, "templates", "fedora-rawhide.tpl"),
+            os.path.join(self.homedir, self.username, ".config", "mock.cfg"),
+            os.path.join(self.homedir, self.username, ".config", "mock", "fedora-rawhide-x86_64.cfg"),
+        }
+
+        assert config["default"] is True
+        assert config["target_arch"] == 'x86_64'
+        assert config["template"] == "templated_value"
+        assert config["home_default"] == (1, 2)
+
+        assert config["override_wins_site"] == "site"
+        assert config["override_wins_conf"] == "conf"
+        assert config["override_wins_home_site"] == "home_site"
+        assert config["override_wins_home_conf"] == "home_conf"
+        assert config["override_wins_template"] == "template"
+
+    def teardown_method(self):
+        shutil.rmtree(self.homedir)