patman: additionally honor a local .patman config file

This enables versioning a project specific patman configuration file.
It also makes it possible to declare the project name, which is not a
useful thing to do in $HOME/.patman.  A new test is added, along
updated documentation.

Signed-off-by: Maxim Cournoyer <maxim.cournoyer@savoirfairelinux.com>
Reviewed-by: Simon Glass <sjg@chromium.org>

tools/patman/test_settings.py

@@ -0,0 +1,67 @@
+# SPDX-License-Identifier: GPL-2.0+
+#
+# Copyright (c) 2022 Maxim Cournoyer <maxim.cournoyer@savoirfairelinux.com>
+#
+
+import argparse
+import contextlib
+import os
+import sys
+import tempfile
+
+from patman import settings
+from patman import tools
+
+
+@contextlib.contextmanager
+def empty_git_repository():
+    with tempfile.TemporaryDirectory() as tmpdir:
+        os.chdir(tmpdir)
+        tools.run('git', 'init', raise_on_error=True)
+        yield tmpdir
+
+
+@contextlib.contextmanager
+def cleared_command_line_args():
+    old_value = sys.argv[:]
+    sys.argv = [sys.argv[0]]
+    try:
+        yield
+    finally:
+        sys.argv = old_value
+
+
+def test_git_local_config():
+    # Clearing the command line arguments is required, otherwise
+    # arguments passed to the test running such as in 'pytest -k
+    # filter' would be processed by _UpdateDefaults and fail.
+    with cleared_command_line_args():
+        with empty_git_repository():
+            with tempfile.NamedTemporaryFile() as global_config:
+                global_config.write(b'[settings]\n'
+                                    b'project=u-boot\n')
+                global_config.flush()
+                parser = argparse.ArgumentParser()
+                parser.add_argument('-p', '--project', default='unknown')
+                subparsers = parser.add_subparsers(dest='cmd')
+                send = subparsers.add_parser('send')
+                send.add_argument('--no-check', action='store_false',
+                                  dest='check_patch', default=True)
+
+                # Test "global" config is used.
+                settings.Setup(parser, 'unknown', global_config.name)
+                args, _ = parser.parse_known_args([])
+                assert args.project == 'u-boot'
+                send_args, _ = send.parse_known_args([])
+                assert send_args.check_patch
+
+                # Test local config can shadow it.
+                with open('.patman', 'w', buffering=1) as f:
+                    f.write('[settings]\n'
+                            'project: guix-patches\n'
+                            'check_patch: False\n')
+                settings.Setup(parser, 'unknown', global_config.name)
+                args, _ = parser.parse_known_args([])
+                assert args.project == 'guix-patches'
+                send_args, _ = send.parse_known_args([])
+                assert not send_args.check_patch